Aalderink, R. H. and R. Jovin (1997). "Estimation of the photosynthesis/irradiance (P/I) curve parameters from light and dark bottle experiments." Journal of Plankton Research 19(11): 1713-1742.
Light and dark bottle experiments, carried out in three systems in the Netherlands, were used to estimate the parameters of models relating the oxygen production rate to incident light intensity. The maximum production rate (P-M) and the light saturation constant (I-S) were estimated using both gross and nett oxygen production data. In the latter case, the community oxygen consumption rate (R-ox) was also estimated. Eight models were compared with respect to goodness of fit, as has been accomplished previously by Jassby and Platt (Limnol. Oceanogr., 21, 540-547, 1976) and many others. This study, however, emphasizes the problem of parameter correlation and the consequential usefulness of these type of experiments to identify the P/I curve parameters. The results show that at a 90% level of confidence, the models cannot be distinguished with respect to goodness of fit. However, the models do show distinct differences in parameter correlation. Parameter correlation was shown to be related to the shape of the curve. P/I curves with high convexity were shown to be less sensitive for parameter correlation. In particular, models showing low convexity suffer from over-parameterization, which means that on the basis of the observed production rates it is difficult to discriminate between the parameters. Also, alternative model formulations, using P-M and the initial slope (alpha), were investigated. These formulations produced less parameter correlation. However, for models with low convexity, showing high parameter correlation anyway, the reduction is limited. The use of nett oxygen production data does not show a significant difference in fit at a 90% confidence level. However, measured R-ox from dark bottle experiments tends to be higher than the values found by estimating R-ox from nett oxygen production.

Anderson, T. R. (1993). "A Spectrally Averaged Model of Light Penetration and Photosynthesis." Limnology and Oceanography 38(7): 1403-1419.
A model was developed which predicts the daily photosynthesis of a vertical pigment profile divided into a number of homogeneous layers. A spectral model (irradiance divided into a large number of wavebands) was used to derive simple empirical equations for calculating spectrally averaged values of two parameters-the vertical light attenuation coefficient and the chlorophyll-specific absorption of algae-for each layer as a function of its pigment content and position in the water column. The empirical equations are not dependent on the layer depths chosen, i.e. the same equations can be used for any given set of depths. The spectrally averaged parameters can be used with analytic integrals to give a computationally rapid and accurate result. The model is therefore ideally suited for general circulation models.

Anning, T., H. L. MacIntyre, et al. (2000). "Photoacclimation in the marine diatom Skeletonema costatum." Limnology and Oceanography 45(8): 1807-1817.

Antoine, D. and A. Morel (1996). "Oceanic primary production .1. Adaptation of a spectral light- photosynthesis model in view of application to satellite chlorophyll observations." Global Biogeochemical Cycles 10(1): 43-55.
A global equation, designed to estimate the column-integrated oceanic primary production realized by a given phytoplankton biomass under various environmental conditions, is used to develop a practical method to assess the primary production (P) from the chlorophyll concentration as provided by satellite imagery. This basic equation combines three terms, namely the photosynthetically available radiation impinging at the sea, surface, PAR(0+), the column-integrated chlorophyll content, < Chl >(tot), and the cross section for photosynthesis per unit of chlorophyll, Psi*. Global monitoring of incident irradiance and near-surface algal biomass is now achievable from space, and thus the next step toward a monitoring of oceanic primary production would be to dispose in parallel of a ''climatological field'' of the Psi* quantity. Actually, Psi* depends on the two other terms of the equation (PAR(0+) and < Chl >(tot)), and in addition, on temperature (also detectable from satellite). Therefore such a ''climatological field'' is variable and complex and it can be conveniently replaced by lookup tables allowing easy interpolation. The entries are date, latitude, cloudiness, temperature, and remotely sensed chlorophyll concentration. This upper layer concentration is extended downward owing to previous results of a statistical analysis of the chlorophyll vertical distribution; accordingly, two parallel tables, corresponding to well-mixed or stratified upper layers with uniform or non uniform chlorophyll vertical profiles, respectively, are constructed. These tables are produced by systematically using a previously published spectral light-photosynthesis model. For such extensive computations, the model necessarily relies on, and is operated with, a standard set of ecological and physiological parameters. Therefore sensitivity analyses have been carried out in view of assessing the impact on Psi*, and on the resulting production of deviations in these parameters or parameterizations, vis-a-vis the standard values or formulations which were adopted when building the tables. The effects of the biomass vertical structure, of possible light and temperature adaptation, and of the presence of degraded pigments are among the sensitivity studies which have been performed. The method as proposed can accomodate any improvement and complexity in parameterization to the extent that additional computation time is faced only when generating the lookup tables, not when using them in conjunction with satellite data.

Arar, E. J. (1997). Method 446.0: In vitro determination of chlorophylls a, b, c1 + c2 and pheopigments in marine and freshwater algae by visible spectrophotometry. Cincinnati, OH 45268, National Exposure Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency: 1-26.

Armbrust, E. V. (2000). "Structural features of nuclear genes in the centric diatom Thalassiosira weissflogii (Bacillariophyceae)." J. Phycol. 36(5): 942-946.
Thalassiosira weissflogii (Grun.) Fryxell et Hasle is one of the more commonly studied centric diatoms, and yet molecular studies of this organism are still in their infancy. The ability to identify open reading frames and thus distinguish between introns and exons, coding and noncoding sequence is essential to move from nuclear DNA sequences to predicted amino acid sequences. To facilitate the identification of open reading frames in T. weissflogii, two newly identified nuclear genes encoding -tubulin and t -complex polypeptide (TCP)-{gamma}, along with six previously published nuclear DNA sequences, were examined for general structural features. The coding region of the nuclear open reading frames had a G + C content of about 49% and could readily be distinguished from noncoding sequence due to a significant difference in G + C content. The introns were uniformly small, about 100 base pairs in size. Furthermore, the 5' and 3' splice sites of introns displayed the canonical GT/AG sequence, further facilitating recognition of noncoding regions. Six of the nuclear open reading frames displayed relatively little bias in the use of synonymous codons, as exemplified by the cDNAs encoding -tubulin and TCP-{gamma}. Two open reading frames displayed strong bias in the use of particular codons (although the codons used were different), as exemplified by the cDNA encoding fucoxanthin chlorophyll a/c binding protein. Knowledge of codon bias should facilitate, for example, design of degenerate PCR primers and potential heterologous reporter gene constructs.

Austin, R. W. (1974). Inherent spectral radiance signatures of the ocean surface, in Ocean Color Analysis. San Diego, Ca, Scripps Institute of Oceanography: 2.1-2.20.

Barber, M. E., S. T. J. Juul, et al. (1999). "Determining primary productivity of Lake Roosevelt with C-14." Journal of Environmental Engineering-Asce 125(8): 747-754.

Barkmann, W. and J. D. Woods (1996). "On using a Lagrangian model to calibrate primary production determined from in vitro incubation measurements." Journal of Plankton Research 18(5): 767-788.
This paper discusses an observing system simulation experiment which reveals the difference in primary production of (i) phytoplankton moving freely in the turbulent mixed layer of the upper ocean and (ii) a sample of the same population held in a bottle at fixed depths. The results indicate the tendency of incubation measurements to overestimate phytoplankton production rates by up to 40%. Differences in primary production depend to a first approximation on the vertical extent of mixing and on water turbidity. A simple model was constructed leading to a non-linear calibration function which relates the difference in primary production to surface irradiance, mixing depth and to the depth of the euphotic zone. This function has been applied to calibrate the production rates simulated at fixed depths, and the corrected values were verified by comparisons with productivities in the turbulent environment. The calibration function was found to be capable of reducing the differences significantly.

Barlow, R. G., R. F. C. Mantoura, et al. (1999). "Monsoonal influence on the distribution of phytoplankton pigments in the Arabian Sea." Deep-Sea Research Part Ii-Topical Studies in Oceanography 46(3-4): 677-699.
Variations in the distribution of chemotaxonomic pigments were monitored in the Arabian Sea and the Gulf of Oman at the end of the SW monsoon in September 1994 and during the inter-monsoon period in November/December 1994 to determine the seasonal changes in phytoplankton composition. The Gulf of Oman was characterized by sub-surface chlorophyll maxima at 20-40 m during both seasons, and low levels of divinyl chlorophyll a indicated that prochlorophytes did not contribute significantly to the total chlorophyll a. Prymnesiophytes (19'- hexanoyloxyfucoxanthin), diatoms (fucoxanthin) and chlorophyll b containing organisms accounted for most of the phytoplankton biomass in September, while prymnesiophytes dominated in November/December. In the Arabian Sea in September, high total chlorophyll a concentrations up to 1742 ngl(-1) were measured in the coastal upwelling region and a progressive decline was monitored along the 1670 km offshore transect to oligotrophic waters at 8 degrees N. Divinyl chlorophyll a was not detected along this transect except at the two most southerly stations where prochlorophytes were estimated to contribute 25-30% to the total chlorophyll a. Inshore, the dominance of fucoxanthin and/or hexanoyloxyfucoxanthin indicated that diatoms and prymnesiophytes generally dominated the patchy phytoplankton community, with zeaxanthin-containing Synechococcus also being important, especially in surface waters. At the southern oligotrophic localities, Synechococcus and prochlorophytes dominated the upper 40 m and prymnesiophytes were the most prominent at the deep chlorophyll maximum. During the inter- monsoon season, total chlorophyll a concentrations were generally half those measured in September and highest levels were found on the shelf (1170 ngl(-1)). Divinyl chlorophyll a was detected at all stations along the Arabian Sea transect, and we estimated that prochlorophytes contributed between 3 and 28% to the total chlorophyll a, while at the two oligotrophic stations this proportion increased to 51-52%. While procaryotes were more important in November/December than September, eucaryotes still accounted for > 50% of the total chlorophyll a. Pigment/total chlorophyll a ratios indicated that 19'- hexanoyloxyfucoxanthin-containing prymnesiophytes were the dominant group, although procaryotes accounted for 65% at the two southerly oligotrophic stations. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.

Barlow, R. G., R. F. C. Mantoura, et al. (1998). "Evolution of phytoplankton pigments in mesocosm experiments." Estuarine Coastal and Shelf Science 46: 15-22.
Changes in pigments, biominerals and particulate organic carbon (POC) were investigated in nutrient controlled mesocosms dominated by diatoms and Emiliania huxleyi. A rapid increase in pigments was observed in the first 3-6 days of the experiment after the mesocosms were enriched with nitrate, phosphate and silicate (N/P/Si), or nitrate and phosphate only (N/P). Pigment concentrations then declined steadily to Day 17-19, after which a secondary increase was again monitored in the final 10 days. High concentrations of fucoxanthin were measured in all the mesocosms that were sampled, and the data indicated that the E. huxleyi cells were producing significant levels of fucoxanthin in addition to hexanoyloxyfucoxanthin. There were concomitant increases and decreases in POC and CaCO3, and in SiO2 in the N/P/Si-enriched mesocosms. Phytoplankton-carbon/POC ratios showed that the phytoplankton accounted for 60-90% of the POC during exponential growth, whereas this proportion was < 50% in the decline phase. High fucoxanthin/ hexanoyloxyfucoxanthin (fuc/hex) ratios in the N/P/Si-enriched mesocosms suggested that a significant fraction of the biomass increase was due to diatoms, while the smaller ratios in the N/P-enriched mesocosms were associated with the dominance of coccolithophores. Mean rates of increase in pigments, POC and biominerals were estimated for each mesocosm and compared with the rate of uptake of nutrients. (C) 1998 Academic Press Limited.

Baumert, H. (1996). "On the theory of photosynthesis and growth in phytoplankton .1. Light limitation and constant temperature." Internationale Revue Der Gesamten Hydrobiologie 81(1): 109-139.
Assuming constant temperature and light limitation, for reversible photoinhibition and photoadaptation in phytoplankton two new modelling approaches are presented. The first follows an idea of JONES and KoK (1966) and describes photoinhibition as a consequence of the serial structure of the Z-scheme. The second interpretes photoadaptation as a dynamic equilibrium of the intracellular synthesis and dilution of Chlorophyll by other carbon compounds during cell growth. Together both ideas form a closed system of equations for the dynamical description of photosynthesis, photoadaptation, reversible photoinhibition and growth in phytoplankton. To determine the seven bulk parameters of the model from measured data for a given species and temperature, three quasi-steady, fully adapted light curves are needed: the P-l, gamma-I and mu-I curves (P: specific photosynthetic rate [gC (gChl)(-1)s(-1)], gamma: Chl-carbon ratio, mu: carbon-specific growth rate [s(-1)], I: light intensity). Given these curves, at compensation light intensity their initial slopes alpha, beta, delta and the (maximum) value of gamma have to be estimated; at saturation level the (minimum) value of gamma is needed. The last bulk parameters of the model are the compensation light intensity and the optimum- growth light intensity. The model performs well compared with laboratory measurements of quasi-steady, fully adapted populations. Its dynamic transient behavior exhibits features which are known from semi-quantitative studies in the field and in the laboratory. In particular, the striking asymmetry observed in shift-up and shift-down adaptation experiments is explained by the equations. In an appendix a detailed comparison between target and queuing theory is given and it is shown that the former appears to be more adequate for describing the primary reactions of photosynthesis.

Bautista, B. and F. JimenezGomez (1996). "Ultraphytoplankton photoacclimation through flow cytometry and pigment analysis of mediterranean coastal waters." Scientia Marina 60: 233-241.
Prochlorophytes, cyanobacteria and eukaryotic ultraplankton from coastal waters of the western Mediterranean Sea were analyzed by flow cytometry to obtain measurements of cell abundance, relative fluorescence per cell (related to cellular pigment content) and relative light scatter per cell (related to cellular size). Cyanobacteria were the dominant group followed by small eukaryotic cells and prochlorophytes. The depth distribution of these ultraplanktonic components in the euphotic layer showed a decrease in the cell abundance with depth in parallel to the decrease of irradiance. Relative cellular light scatter showed similar distributions at the different depths, indicating no variation in the cell size. However, relative cellular fluorescence showed a clear increase with depth, both in red (chlorophyll a) and orange (phycoerythrin) fluorescence, suggesting photoacclimation. This was confirmed by the increase in cellular chlorophyll a concentration with depth, as derived from fractionated chlorophyll a analysis. The total fluorescence (F), calculated from the integration of the flow cytometric measurements of cellular fluorescence weighed by the cell abundance for each group, was significatively correlated with the fractionated chlorophyll a measurements, suggesting F as a useful means to characterize the group composition of bulk chlorophyll a, and therefore both as rough estimators of ultraphytoplankton biomass.

Beardall, J., T. Burgerwiersma, et al. (1994). "Studies on Enhanced Post-Illumination Respiration in Microalgae." Journal of Plankton Research 16(10): 1401-1410.

Behrenfeld, M. J. and P. G. Falkowski (1997). "Photosynthetic rates derived from satellite-based chlorophyll concentration." Limnology and Oceanography 42(1): 1-20.
We assembled a dataset of C-14-based productivity measurements to understand the critical variables required for accurate assessment of daily depth-integrated phytoplankton carbon fixation (PPeu) from measurements of sea surface pigment concentrations (C-sat). From this dataset, we developed a light-dependent, depth-resolved model for carbon fixation (VGPM) that partitions environmental factors affecting primary production into those that influence the relative vertical distribution of primary production (P-z) and those that control the optimal assimilation efficiency of the productivity profile (P-opt(B)). The VGPM accounted for 79% of the observed variability in P-z and 86% of the variability in PPeu by using measured values of P-opt(B). Our results indicate that the accuracy of productivity algorithms in estimating PPeu is dependent primarily upon the ability to accurately represent variability in P-opt(B). We developed a temperature-dependent P-opt(B), model that was used in conjunction with monthly climatological images of C-sat, sea surface temperature, and cloud-corrected estimates of surface irradiance to calculate a global annual phytoplankton carbon fixation (PPannu) rate of 43.5 Pg C yr(-1). The geographical distribution of PPannu was distinctly different than results from previous models. Our results illustrate the importance of focusing P-opt(B) model development on temporal and spatial, rather than the vertical, variability.

Behrenfeld, M. J., J. T. Randerson, et al. (2001). "Biospheric primary production during an ENSO transition." Science 291(30 March): 2594-2597.

Beletsky, D., W. P. Oconnor, et al. (1997). "Numerical simulation of internal Kelvin waves and coastal upwelling fronts." Journal of Physical Oceanography 27(7): 1197-1215.
Two three-dimensional primitive equation numerical ocean models are applied to the problem of internal Kelvin waves and coastal upwelling in the Great Lakes. One is the Princeton Ocean Model (POM) with a terrain-following (sigma) vertical coordinate, and the other is the Dietrich/Center for Air Sea Technology (DIECAST) model with constant z-level coordinates. The sigma coordinate system is particularly convenient for simulating coastal upwelling, while the z-level system might be better for representing abrupt topographic changes. The models are first tested with a stratified idealized circular lake 100 km in diameter and 100 m deep. Two bottom topographies are considered: a flat bottom and a parabolic depth profile. Three rectilinear horizontal grids are used: 5, 2.5, and 1.25 km. The POM was used with 13 vertical levels, while the DIECAST model was tested with both 13 and 29 vertical levels. The models are driven with an impulsive wind stress imitating the passage of a weather system. In the case of the Aar-bottom basin, the dynamical response to light wind forcing is a small amplitude internal Kelvin wave. For both models, the speed of the Kelvin wave in the model is somewhat less than the inviscid analytic solution wave speed. In the case of strong wind forcing, the thermocline breaks the surface (full upwelling) and a strong surface thermal front appears. After the wind ceases, the edges of this thermal front propagate cyclonically around the lake, quite similar to an internal Kelvin wave. In the case of parabolic bathymetry, Kelvin wave and thermal front propagation is modified by interaction with a topographic wave and a geostrophic circulation. In both models, higher horizontal resolution gives higher wave and frontal speeds. Horizontal resolution is much more critical in the full upwelling case than in the Kelvin wave case. Vertical resolution is not as critical. The models are also applied to Lake Michigan to determine the response to strong northerly winds causing upwelling along the eastern shore. The results are more complex than for the circular basin, but clearly show the characteristics of cyclonically propagating thermal fronts. The resulting northward warm front propagation along the eastern shore compares favorably with observations of temperature fluctuations at municipal water intakes after a storm, although the model frontal speed was less than the observed speed.

Beletsky, D., J. H. Saylor, et al. (1999). "Mean circulation in the Great Lakes." Journal of Great Lakes Research 25(1): 78-93.
In this paper new maps ar-e presented of mean circulation in the Great Lakes, employing long-term current observations from about 100 Great Lakes moorings during the 1960s to 1980s. Knowledge of the mean circulation in the Great Lakes is important for ecological and management issues because it provides an indication of transport pathways of nutrients and contaminants on longer time scales. Based on the availability of data, summer circulation patterns in all of the Great Lakes, winter circulation patterns in all of the Great Lakes except Lake Superior, and annual circulation patterns in Lakes EP-ie,: Michigan, and Ontario were derived. Winter currents are generally stronger than summer currents, and therefore, annual circulation closely resembles winter circulation. Circulation patterns tend to be cyclonic (counterclockwise) in the larger lakes (Lake Huron, Lake Michigan, and Lake Superior) with increased cyclonic circulation in winter. In the smaller lakes (Lake Erie and Lake Ontario), winter circulation is characterized by a two-gyre circulation pattern. Summer circulation in the smaller lakes-is different; predominantly cyclonic in Lake Ontario and anticyclonic in Lake Erie.

Berner, T., Z. Dubinsky, et al. (1989). "Photoadaptation and the "package effect" in Dunaliella tertiolecta (Chlorophyceae)." J. Phycol. 25(70-78).

Berner, T. and A. Sukenik (1998). "Photoacclimation in photosynthetic microorganisms: An ultrastructural response." Israel Journal of Plant Sciences 46(2): 141-146.

Berner, T. and A. Sukenik (1998). "Photoacclimation in photosynthetic microorganisms: An ultrastructural response." Israel Journal of Plant Sciences 46(2): 141-146.

Berry, H. A. and C. A. Lembi (2000). "Effects of temperature and irradiance on the seasonal variation of a Spirogyra (Chlorophyta) population in a midwestern lake (U.S.A.)." J. Phycol. 36(5): 841-a-851.
Although Spirogyra Link (1820) is a common mat-forming filamentous alga in fresh waters, little is known of its ecology. A 2-year field study in Surrey Lake, Indiana, showed that it grew primarily in the spring of each year. The population consisted of four morphologically distinct filamentous forms, each exhibiting its own seasonal distribution. A 45-m-wide filament was present from February to late April or early May, a 70-m-wide form was present from late April to mid-June, a 100-m-wide form was present from February to mid-June, and a 130-m-wide form appeared only in February of 1 of 2 study years. The 70- and 100-m-wide forms contributed to the peak amount of biomass observed in late May and early June. Multiple regression analysis indicated that the presence of the 45-, 70-, and 100-m-wide forms was negatively correlated with temperature. Presence of the 130-m-wide form was negatively correlated with irradiance. Isolates of these filament forms were exposed to temperature (15, 25, and 35 C)/irradiance (0, 60, 200, 400, 900, and 1500 molm-2s-1) combinations in the laboratory. Growth rates of the 45-m-wide form were negative at all irradiances at 35 C, suggesting that this form is susceptible to high water temperatures. However, growth rates of the other forms did not vary at the different temperatures or at irradiances of 60 molm-2s-1 or above. Net photosynthesis was negative at 35 C and 1500 molm-2s-1 for the 100- and 130-m-wide forms but positive for the 70-m-wide form. All forms lost mat cohesiveness in the dark, and the 100- and 130-m-wide forms lost mat cohesiveness under high irradiances and temperature. Thus, the morphological forms differed in their responses to irradiance and temperature. We hypothesize that the rapid disappearance of Spirogyra populations in the field is due to loss of mat cohesiveness under conditions of reduced net photosynthesis, for example, at no to low light for all forms or at high light and high temperatures for the 100- and 130-m-wide forms. Low light conditions can occur in the interior of mats as they grow and thicken or under shade produced by other algae.

Berthon, J. F. and A. Morel (1992). "Validation of a Spectral Light-Photosynthesis Model and Use of the Model in Conjunction with Remotely Sensed Pigment Observations." Limnology and Oceanography 37(4): 781-796.
The predictions of a spectral light-photosynthesis model are compared with field data. The model calculations are based on pigment (chlorophyll and pheophytin) and temperature profiles and, when available, on irradiance recorded on deck. The agreement between computed and measured production values is satisfying over the full range (10(-4)-1 g C m-3 d-1 or 0.03-10 g C m-2 d-1). It is better when C-14 fixation has been measured via the in situ method; a small bias appears when production was measured on deck (simulated in situ method). In both cases however the standard deviation remains similar and computed and measured column production agrees within a factor of approximately-3. The same data set is also used to predict column production from pigment concentration within only the top layer, as supposedly remotely sensed. The model is run in combination with pigment profiles, which are "reconstructed" (in magnitude and shape) as a function of the upper layer concentration with statistical relationships previously established. The agreement between computed and measured production (within a factor 3.3 at 1 SD) is encouraging. The model uses mean and constant physiological parameters, which actually vary in the natural environment. Among these parameters, the Chl-specific absorption by phytoplankton algae and, to a lesser extent, the maximum quantum yield for growth are crucial. Very likely their variations are the main causes of divergence between predicted and field values.

Bolgrien, D. W. and A. S. Brooks (1992). "Analysis of Thermal Features of Lake-Michigan from Avhrr Satellite Images." Journal of Great Lakes Research 18(2): 259-266.
The seasonal dynamics of thermal features in Lake Michigan were studied using numerous sea surface temperature images acquired from the NOAA Advanced Very High Resolution Radiometer from May-December, 1990. In southern Lake Michigan, the vernal thermal front moved offshore and to the north between 7 May 1990 and 11 June 1990. Inshore of the front, surface temperatures were > 10.0-degrees-C while offshore surface temperatures remained < 4.5-degrees-C. In northern Lake Michigan, thermal fronts were not prevalent until late June. Southern Green Bay consistently contained the warmest water in Lake Michigan and exceeded 15.0-degrees-C in May. Warm bay- water frequently mixed with cooler lake-water through the channels at the north end of the bay. Warm water plumes remained intact for several days with S/SW winds but were quickly obliterated by a N/NE wind. Upwelling was most conspicuous along the eastern shore of the lake. Depending on wind direction, upwelled water formed broad continuous nearshore bands or isolated patches of relatively cold water. Evidence of upwelling 1-3 days after the instigating wind event suggested oscillations of internal waves. Our study shows that the frequent acquisition of satellite images is useful to describe significant thermal features in a large lake.

Bolgrien, D. W. and A. S. Brooks (1992). "Analysis of Thermal Features of Lake-Michigan from Avhrr Satellite Images." Journal of Great Lakes Research 18(2): 259-266.
The seasonal dynamics of thermal features in Lake Michigan were studied using numerous sea surface temperature images acquired from the NOAA Advanced Very High Resolution Radiometer from May-December, 1990. In southern Lake Michigan, the vernal thermal front moved offshore and to the north between 7 May 1990 and 11 June 1990. Inshore of the front, surface temperatures were > 10.0-degrees-C while offshore surface temperatures remained < 4.5-degrees-C. In northern Lake Michigan, thermal fronts were not prevalent until late June. Southern Green Bay consistently contained the warmest water in Lake Michigan and exceeded 15.0-degrees-C in May. Warm bay- water frequently mixed with cooler lake-water through the channels at the north end of the bay. Warm water plumes remained intact for several days with S/SW winds but were quickly obliterated by a N/NE wind. Upwelling was most conspicuous along the eastern shore of the lake. Depending on wind direction, upwelled water formed broad continuous nearshore bands or isolated patches of relatively cold water. Evidence of upwelling 1-3 days after the instigating wind event suggested oscillations of internal waves. Our study shows that the frequent acquisition of satellite images is useful to describe significant thermal features in a large lake.

Bouman, H. A., T. Platt, et al. (2000). "Bio-optical properties of the subtropical North Atlantic. I. Vertical variability." Marine Ecology-Progress Series 200: 3-18.

Bouman, H. A., T. Platt, et al. (2000). "Bio-optical properties of the subtropical North Atlantic. II. Relevance to models of primary production." Marine Ecology-Progress Series 200: 19-34.

Bowles, N. D., H. W. Paerl, et al. (1985). "Effective solvents and extractions periods employed in phytoplankton carotenoid and chlorophyll determination." Can. J. Fish. Aquat. Sci. 42: 1127-1131.

Boyum, K. W. and A. S. Brooks (1988). "The Effect of Selenium in Water and Food on Daphnia Populations." Archives of Environmental Contamination and Toxicology 17(5): 555-560.

Boyum, K. W. and A. S. Brooks (1988). "The Effect of Selenium in Water and Food on Daphnia Populations." Archives of Environmental Contamination and Toxicology 17(5): 555-560.

Brooks, A. S. and D. N. Edgington (1994). "Biogeochemical control of phosphorus cycling and primary production in lake Michigan." Limnol. Oceanogr. 39(4): 961-968.

Brooks, A. S. and D. N. Edgington (1994). "Biogeochemical Control of Phosphorus Cycling and Primary Production in Lake-Michigan." Limnology and Oceanography 39(4): 961-968.
A 3-yr study in Lake Michigan has shown a 27 mmol P m-2 increase in the mass of total P (TP) in the water during spring when the lake is mixed from surface to sediment. This value is an order of magnitude greater than the annual P input from external sources. TP changed in concert with increases in chlorophyll a and organic N and decreases in nitrate and soluble Si. The concentration of soluble reactive PO43- (SRP) remained relatively constant throughout the study. We hypothesize that the SRP concentration is maintained by a chemical equilibrium with calcium-phosphate species. The increased mass of TP arises from the sequestering of P by algae which displaces the chemical equilibrium and allows more P to be released to the water from the sediments. Solar irradiance and the duration of mixing determine the magnitude of the spring bloom and the demand for P that must be supplied through the flux of P from the sediments to the overlying water.

Brooks, A. S. and B. G. Torke (1977). "Vertical and seasonal distribution of chlorophyll a in Lake Michigan." Journal of Fisheries Research Board of Canada 34(12): 2280-2287.

Brosnan, T. M. and G. D. Cooke (1987). "Response of Silver Lake trophic state to artificial circulation." Lake and Reservoir Management 3: 66-75.

Brown, M. R., G. A. Dunstan, et al. (1993). "The Influence of Irradiance on the Biochemical-Composition of the Prymnesiophyte Isochrysis Sp (Clone T-Iso)." Journal of Phycology 29(5): 601-612.
The effect of irradiance on the biochemical composition of the prymnesiophyte microalga, Isochrysis sp. (Parke; clone T-ISO) a popular species for mariculture, were examined. Cultures were grown under a 12:12 h light:dark (L:D) regime at five irradiances ranging from 50 to 1000 mu E.m(-2).s(-1) and harvested at late-logarithmic phase for analysis of biochemical composition. Gross composition varied over the range of irradiances. The highest levels of protein were present in cells from cultures grown at 100 and 250 mu E.m(-2).s(-1), and minimum levels of carbohydrate and lipid occurred at 50 mu E.m(-2).s(-1). Because the cell dry weight was reduced at lower irradiances, different trends were evident when results were expressed as percentage of dry weights. Protein percentages were highest at 50 and 100 mu E.m(-2).s(-1) and carbohydrate at 100 mu E.m(-2).s(-1) The composition of amino acids did not differ over the range of irradiances. Glutamate and aspartate were always present in high proportions (9.0-13.5%) histidine, methionine, tryptophan, cystine, and hydroxy-proline were minor constituents (0.0-2.6%). Glucose was the predominant sugar in all cultures, ranging from 23.0% (50 mu E.m(-2).s(-1)) to 45.0% (100 mu E.m(-2).s(-1)) of total polysaccharide. No correlation was found between the proportion of any of the sugars and irradiance. The proportions of the lipid class components and fatty acids showed little change with irradiance. The main fatty acids were 14:0, 16:0, 16:1(n-7), 18:1(n-9), 18:3(n-3), 18:4(n-3), 18:5(n-3), and 22:6(n-3). Proportions of 22:6(n-3) increased, whereas 18:3(n-3), 18:3(n-6), and 18:4(n-3) decreased, with increasing irradiance. Pigment concentrations were highest in cultures grown at 50 mu E.m(-2).s(-1), except for fucoxanthin and diadinoxanthin (100 mu E.m(-2).s(-1)). The concentrations of accessory pigments correlated with chlorophyll a, which decreased in concentration with increasing irradiance.

Brown, M. R. and S. W. Jeffrey (1992). "Biochemical-Composition of Microalgae from the Green Algal Classes Chlorophyceae and Prasinophyceae .1. Amino-Acids, Sugars and Pigments." Journal of Experimental Marine Biology and Ecology 161(1): 91-113.
The biochemical composition of 10 species of green microalgae was determined. The species examined included 3 marine chlorophytes (Chlorella sp. (CS-247), Chlorella sp. (CS-195) and Stichococcus sp.), and 6 marine prasinophytes (Pyramimonas cordata, Tetraselmis chui, a temperate and a tropical strain of Micromonas pusilla, Pycnococcus provasolii, and one unidentified coccoid prasinophyte (CS-126)). Pigment composition (e.g. presence of the chlorophyll c-like pigment Mg 2,4 divinyl pheoporphyrin a5 monomethyl ester (Mg 2,4 D); and lutein, prasinoxanthin or siphonaxanthin-like carotenoids) assisted in the taxonomy of the new strains. One freshwater chlorophyte (Chlorella protothecoides) was included for comparison. The protein content of all species ranged from 15.2-25.6% of dry weight except for the tropical M. pusilla (5.5%), and carbohydrate ranged from 10.8-16.7% for all species except Chlorella sp. (CS-195) (5.9%). Total lipid varied from 8.5-18.4% of dry weight among the species; chlorophyll a from 0.23-1.54% of dry weight. Amino acid profiles showed only minor variations between species, with the exception of tryptophan and arginine. Two species, Chlorella protothecoides and Chlorella sp. (CS-195) had lower proportions of tryptophan (< 0.5% of total amino acids) compared to the other species (1.0- 1.8%) while arginine showed large variations across all species ranging from 4.7% (tropical M. pusilla) to 15.0% (T. chui). Glucose was the dominant sugar in the polysaccharide fraction of eight of the species. Galactose was the major sugar in the unidentified prasinophyte (CS-126) accounting for 54% of sugars. A wide range of sugars was found in Chlorella sp. (CS- 195) with glucose making up only 19.3%. The possible use of the species in mariculture, based on their biochemical composition, is also discussed.

Butterwick, C., S. I. Heaney, et al. (1987). "The Influence of Temperature on Algal Growth." British Phycological Journal 22(3): 301-301.

Carder, K. L., R. F. Chen, et al. (1999). ATBD 19: Case 2 waters Chlorophyll a. MODIS Ocean Science Team Algorithm Theoretical Basis Document. St. Petersburg, Florida, Marine Science Department, University of South Florida. version 5: 1-45.

Chaturvedi, N., A. Narain, et al. (1998). "Phytoplankton pigment/temperature relationship in the Arabian Sea." Indian journal of marine sciences 27(3/4): 286.

Chen, X., S. E. Lohrenz, et al. (2000). "Distribution and controlling mechanisms of primary production on the Louisiana-Texas continental shelf." Journal of Marine Systems 25(2): 179-207.

Clark, D. K. (1997). Bio-optical algorithms: case 1 waters. MODIS Ocean Science Team Algorithm Theoretical Basis Document. Washington, D.C., National Oceanic and Atmospheric Administration. version 1.2.

Clark, D. R. (2001). "Growth rate relationships to physiological indices of nutrient status in marine diatoms." J. Phycol. 37(2): 249-256.
The growth of two species of marine diatom, Thalassiosira weissflogii (Grunow) and Thalassiosira pseudonana (Hustedt), was followed in batch cultures at four concentrations of dissolved inorganic carbon from N- and C-replete lag phase into N- and/or C-deplete stationary phase. Results describe the relationship between carbon-specific growth rate (C) and chl a:carbon (chl a:C) and glutamine:glutamate (gln:glu) ratios with changes in the cells' nutritional status (N:C), during the utilization of either NO3- or NH4+. The use of the gln:glu ratio as an index of N:C requires further clarification. For both species and N sources, N stress resulted in a decrease in C, chl a:C, and N:C relative to Cmax values, whereas C stress resulted in a decrease in C and an increase in chl a:C and N:C relative to Cmax values. Both species attained a chl a:C ratio of approximately 15 gg-1 at Cmax using either N source. However, this value was not necessarily an indicator of maximal growth rate. NC colimitation resulted in decreased C to values less than 20% of Cmax with only minor changes in chl a:C and N:C relative to Cmax values. Chl a:C results suggest a similarity between the light stress and C stress responses of marine diatoms. The potential for C stress in the marine environment needs to be addressed.

Coles, J. F. and R. C. Jones (2000). "Effect of temperature on photosynthesis-light response and growth of four phytoplankton species isolated from a tidal freshwater river." Journal of Phycology 36(1): 7-16.
Three cyanobacteria (Microcystis aeruginosa Kutz, emend, Elenkin, Merismopedia tenuissima Lemmermann, and Oscillatoria sp.) and one diatom (Aulacoseira granulata var, angustissima O. Mull. emend, Simonsen) were isolated from the tidal freshwater Potomac River and maintained at 23 degrees C and 40 mu mol photons . m(-2) . s(-1) on a 16:8 L:D cycle in unialgal culture, Photosynthetic parameters were determined in nutrient- replete cultures growing exponentially at 15, 20, 25, and 30 degrees C by incubation with C-14 at six light levels. P-max(B) was strongly correlated with temperature over the entire range for the cyanobacteria and from 15 to 25 degrees C for Aulacoseira, with Q(10) ranging from 1.79 to 2.67. The alpha values demonstrated a less consistent temperature pattern, Photosynthetic parameters indicated an advantage for cyanobacteria at warmer temperatures and in light-limited water columns. p(max)(B) and I-k values were generally lower than comparable literature and field values, whereas a was generally higher, consistent with a somewhat shade acclimated status of our cultures. Specific growth rate (mu), as measured by chlorophyll change, was strongly influenced by temperature in all species, Oscillatoria had the highest mu at all temperatures, joined at lower temperatures by Aulacoseira and at higher temperatures by Microcystis, Values of mu for Aulacoseira were near the low end of the literature range for diatoms consistent with the light-limited status of the cultures. The cyanobacteria exhibited growth rates similar to those reported in other studies. Q(10) for growth ranged from 1.71 for Aulacoseira to 4.16 for Microcystis, Growth rate was highly correlated with P-max(B) for each species and the regression slope coefficients were very similar for three of the species.

Coles, J. F. and R. C. Jones (2000). "Effect of Temperature on Photosynthesis-Light Response and Growth of Four Phytoplankton Species Isolated from a Tidal Freshwater River1." Journal of Phycology 36(1): 7-16(10).

Comparini, E. and A. Fasano (1993). "The effect of temperature on the dynamics of a phytoplankton population." Nonlinear analysis 20(11): 1355.

Cordi, B., M. H. Depledge, et al. (1997). "Evaluation of chlorophyll fluorescence, in vivo spectrophotometric pigment absorption and ion leakage as biomarkers of UV-B exposure in marine macroalgae." Marine Biology 130(1): 41-49.
The photosynthetic fluorescence ratio F-v:F-m, in vivo absorption spectra and ion leakage were evaluated as biomarkers of ambient and elevated UV-B (280 to 320 nm) exposure of the intertidal alga Enteromorpha intestinalis (Chlorophyta) and the sublittoral alga Palmaria palmata (Rhodophyta). Measurements of thallus growth were also used to assess adverse biological effects. Ambient and elevated UV-B significantly inhibited photosynthesis in both species. It was shown that the F-v:F-m ratio is a sensitive, non-specific general biomarker of UV-B exposure in both species. Moreover, the in vivo absorption of what was tentatively identified as chlorophylls a and b as well as phycoerythrin and/or carotenoids, phycoerythrobilin and phycocyanin decreased in a dose-response dependent manner and was associated with a decrease in growth rate in P. palmata. The intertidal alga E. intestinalis showed a greater degree of tolerance to UV-B exposure. These results indicate that changes in the F-v:(F)m ratio together with reductions in in vivo pigment absorption could provide an early quantitative warning of the detrimental effects of UV-B in marine macroalgae.

Cuhel, R. L. and D. R. S. Lean (1987). "Influence of light Intensity, light quality, temperature and daylength on uptake and assimilation of carbon dioxide and sulfate by lake plankton." Can. J. Fish. Aquat. Sci. 44: 2118-2132.

Cuhel, R. L., D. Ortner, et al. (1984). "Night synthesis of protein by algae." Limnol. Oceanogr. 29(4): 731-744.

Cullen, J. J. (1990). "On Models of Growth and Photosynthesis in Phytoplankton." Deep-Sea Research Part a-Oceanographic Research Papers 37(4): 667-683.

Cullen, J. J. and M. R. Lewis (1988). "The kinetics of algal photoadaptation in the context of vertical mixing." J. Plankton Res. 10(5): 1039-1063.

Cunningham, A. (1996). "Variability of in-vivo chlorophyll fluorescence and its implications for instrument development in bio-optical oceanography." Scientia Marina 60: 309-315.
The yield of in-vivo fluorescence per unit of cellular chlorophyll varies markedly according to phytoplankton species and physiological state, and is also highly sensitive to the configuration of the measuring equipment. This means that great caution has to be excercised in the use of fluorescence sensors for in-situ monitoring of chlorophyll concentrations. On the other hand, the sensitivity of fluorescence yield to biological parameters raises the possibility of combining fluorometry with other optical measurements to produce new probes for monitoring the adaptive response of phytoplankton populations to their changing environment.

Dalaka, A., B. Kompare, et al. (2000). "Modelling the effects of environmental conditions on apparent photosynthesis of Stipa bromoides by machine learning tools." Ecological Modelling 129(2-3): 245-257.

Davey, M. C. and S. I. Heaney (1989). "The control of sub-surface maxima of diatoms in a stratified lake by physical, chemical and biological paramters." Journal of Plankton Research 11(6): 1185-1199.

Davey, M. C. and S. I. Heaney (1989). "The Control of Sub-Surface Maxima of Diatoms in a Stratified Lake by Physical, Chemical and Biological Factors." Journal of Plankton Research 11(6): 1185-1199.

Delagiraudiere, I., P. Laborde, et al. (1989). "Hplc Determination of Chlorophylls and Breakdown Products in Surface Microlayers." Marine Chemistry 26(3): 189-204.

Denant, V., A. Saliot, et al. (1991). "Distribution of Algal Chlorophyll and Carotenoid-Pigments in a Stratified Estuary - the Krka River, Adriatic Sea." Marine Chemistry 32(2-4): 285-297.
The detailed distribution of algal chlorophyll and carotenoid pigments was determined around the halocline (freshwater- seawater interface) in the Krka Estuary on the east coast of the Adriatic Sea, in May 1988. After collection of water along the estuary, particulate matter was extracted and analyzed for pigments by high-performance liquid chromotography coupled with absorbance and fluorescence detection. Bottom marine waters were characterized by lower chlorophyll a (chl a) concentration than encountered in surface waters, decreasing downstream from 0.50-mu-g l-1 to 0.16-mu-g l-1 at the marine end-member. The highest concentrations of chl a (up to 26.34-mu-g l-1) were found in the interfacial layer, an particularly at one station located off the city of Sibenik, where high inputs of nutrients supported the accumulation of living algae at the halocline. Fucoxanthin was the most abundant carotenoid, which indicates a euryhaline dominance of diatoms in the estuary, whereas the dinoflagellate-derived carotenoid peridinin was confined to the interfacial and bottom saline waters of the inner estuary. High concentrations of alloxanthin and chl b were found in the interfacial layer, which also suggests an accumulation of Cryptophyceae and green algae in the inner estuary. Phaeophorbides showed higher concentrations in bottom waters than in surface waters, whereas the highest concentrations occurred in the interfacial layer. These high levels could reflect a density trapping of dead cells in an early degradation state, as suggested by the importance of allomerized chl a and chlorophyllide a vs. total chl a, or of faecal pellets originating from zooplankton grazing in the interfacial layer.

Descy, J. P., H. W. Higgins, et al. (2000). "Pigment ratios and phytoplankton assessment in northern Wisconsin lakes." Journal of Phycology 36(2): 274-286.
Nine lakes in northern Wisconsin were sampled from February through September 1996, and HPLC analysis of water column pigments was carried out on epilimnetic seston, pigment distributions were evaluated throughout the water column during summer in Crystal Lake and Little Rock Lake. The purpose of our study was to investigate the use of phytopigments as markers of the main taxonomic groups of algae, As a first approach, multiple regression of marker pigments against chlorophyll a (chl a) was used to derive the best linear combination of the main xanthophylls (peridinin, fucoxanthin, alloxanthin, lutein, and zeaxanthin), A significant regression equation (r(2) = 0.98) was obtained for epilimnion data. The good fit indicates that the chi a:xanthophyll ratios were fairly constant in the epilimnion of the nine lakes over time. Chlorophyll a recalculated from the main xanthophylls in each sample showed good agreement with measured chi a in epilimnetic waters, A second approach used the CHEMTAX program to analyze the same data set. CHEMTAX provided estimates of chi a biomass for all algal classes and allowed distinction between diatoms and chrysophytes, and between chlorophytes and euglenophytes. These results showed a reasonably good agreement with biomass estimates from microscope counts, despite uncertainties associated with differences in sampling procedure. Changes of pigment ratios over time in the epilimnetic waters were also investigated, as well as differences between surface and deep samples of Little Rock Lake and Crystal Lake. We found evidence that changes in the ratio of photoprotective pigments to chi a occurred as a response to changes in light climate. Changes were also observed for certain light-harvesting pigments. The comparison between multiple regression and CHEMTAX analyses for inferring chl a biomass from concentrations of marker pigments highlighted the need to take account of variations in pigment ratio, as well as the need to acquire additional data on the pig ment composition of planktonic algae.

Dodds, W. K. (1992). "A Modified Fiberoptic Light Microprobe to Measure Spherically Integrated Photosynthetic Photon Flux-Density - Characterization of Periphyton Photosynthesis-Irradiance Patterns." Limnology and Oceanography 37(4): 871-878.
A fiber-optic light sensor was modified by adding a broadband filter (420-730 nm) to sense photosynthetic photon flux density. A sphere of acrylic paint added to the fiber tip allowed estimation of spherically integrated irradiance. The modified light probe and an O2 microelectrode allowed 250-mum- resolution photosynthesis-irradiance profiles to be determined. In Ulothrix-dominated periphyton, there was greater ability to utilize low light as depth increased from 0 to 750 mum, and photosynthesis was not saturated up to 1,800 Amol quanta m-2 s- 1. In a benthic diatom assemblage, light attenuation was greater than in the Ulothrix filaments in the top 250 mum, photosynthesis approached saturation at 1,000 mumol quanta m-2 s-1, and photosynthetic rates were extremely low at the 250- and 500-mum depths.

Dodds, W. K., B. J. F. Biggs, et al. (1999). "Photosynthesis-irradiance patterns in benthic microalgae: Variations as a function of assemblage thickness anc community structure." Journal of Phycology 35(1): 42-53.

Doyon, P., B. Klein, et al. (2000). "Influence of wind mixing and upper-layer stratification on phytoplankton biomass in the Gulf of St. Lawrence." Deep-Sea Research Part Ii-Topical Studies in Oceanography 47(3-4): 415-433.
Analyses of CTD profiles collected during 9 cruises in the Gulf of St. Lawrence (1992-1994, Canada) indicate that hydrographic conditions were in close agreement with the physical oceanographic climatology of the Gulf, and that winds during the sampling period were relatively weaker than their corresponding monthly means. Using temperature and salinity profiles with meteorological conditions averaged over 4 days prior to each sampling date, several physical parameters were computed to characterize the hydrodynamic conditions in the euphotic zone. Phytoplankton chlorophyll a biomass (Ch1a) averaged over the euphotic zone was examined, both total and size-fractionated( > 5 and < 5 mu m), in combination with nitrate data. The seasonal pattern in total phytoplankton reflected changes in the large size fraction, the concentration of phytoplankton < 5 Irm being low throughout the year. A modified buoyancy length scale (BL*) was derived from wind- induced turbulence and upper-layer stratification; BL* co- varied with the depth of the surface mixed layer. When considering the proportion of the small size fraction ([Ch1a](small)/[Ch1a](total)), maximum Chla biomass corresponded to intermediate values of BL* (similar to 0.1 m), with phytoplankton concentrations decreasing in the two ends of the buoyancy length spectrum. (C) 1999 Elsevier Science Ltd. All rights reserved.

Duarte, P. (1995). "A Mechanistic Model of the Effects of Light and Temperature on Algal Primary Productivity." Ecological Modelling 82(2): 151-160.
In this work a model of algal primary productivity combining a mechanistic light function with a temperature Arrhenius function is presented. Data on primary productivity obtained with algae acclimated to different environmental conditions was used to test the model. A simple method for model parameter estimation based on regression analysis is described. The parameter estimates can be improved by a non-linear least- squares method (e.g. the Gauss-Newton method) resulting in a significant fit to the observed data as tested by regression analysis. According to the present model, the initial slope of the productivity/light curves is temperature dependent whilst the optimal light intensity is temperature independent. These model predictions were validated by the obtained experimental results.

Dubinsky, Z., P. G. Falkowski, et al. (1986). "Light harvesting and utilization by phytoplankton." Plant Cell Physiology 27: 1335-1349.

Dusenberry, J. A. (1999). "Frequency distributions of phytoplankton single-cell fluorescence and vertical mixing in the surface ocean." Limnology and Oceanography 44(2): 431-435.

Dusenberry, J. A. (2000). "Steady-state single cell model simulations of photoacclimation in a vertically mixed layer: implications for biological tracer studies and primary productivity." Journal of Marine Systems 24(3-4): 201-220.

Dusenberry, J. A., R. J. Olson, et al. (2000). "Field observations of oceanic mixed layer dynamics and picophytoplankton photoacclimation." Journal of Marine Systems 24(3-4): 221-232.

Eilers, P. H. C. and J. C. H. Peeters (1988). "A Model for the Relationship between Light-Intensity and the Rate of Photosynthesis in Phytoplankton." Ecological Modelling 42(3-4): 199-215.

Eilers, P. H. C. and J. C. H. Peeters (1993). "Dynamic Behavior of a Model for Photosynthesis and Photoinhibition." Ecological Modelling 69(1-2): 113-133.
The dynamic behaviour of a simple model for photosynthesis and photoinhibiton, which was published before in this journal, is analysed. The differential equations are simplified and characteristic parameters and time scale are introduced. It is shown that the gradual development of photoinhibition is very important for the interpretation of observations on primary production. The model is used to explain differences between short and long incubations, the effect of intermittent illumination, the influence of prior illumination and hysteresis-effects. Two suggestions for extensions of the model are presented: one for extra consumption of oxygen, coupled to photoinhibition, the other for saturation of production at lower temperatures.

Estrada, M., C. Marrase, et al. (1996). "In vivo fluorescence/chlorophyll a ratio as an ecological indicator in oceanography." Scientia Marina 60: 317-325.
This article reviews the main factors affecting the in vivo fluorescence versus chlorophyll relationships of phytoplankton and presents a case study based on data from three oceanographic cruises carried out, at different times of the year, in the Catalan-Balearic Sea. In all three surveys, the in vivo fluorescence/chlorophyll ratio of the upper euphotic layer samples presented a diel variability with a minimum at or before noon time. The relationships between the spatio-temporal distribution of this variability and characteristics of photosynthesis versus irradiance curves obtained during each cruise are discussed.

Fahnenstiel, G. L., J. F. Chandler, et al. (1989). "Photosynthetic characteristics of phytoplankton communities in Lakes Huron and Michigan: P-I parameters and end-products." Journal of Great Lakes Research 15(3): 394-407.

Fahnenstiel, G. L. and D. Scavia (1987). "Dynamics of Lake Michigan phytoplankton: primary production and growth." Canadian Journal of Fisheries and Aquatic Science 44: 499-508.

Fahnenstiel, G. L. and D. Scavia (1987). "Dynamics of Lake Michigan phytoplankton: recent changes in surface and deep communities." Canadian Journal of Fisheries and Aquatic Science 44: 509-514.

Fahnenstiel, G. L., D. Scavia, et al. (1988). "Impact of Inertial Period Internal Waves on Fixed-Depth Primary Production Estimates." Journal of Plankton Research 10(1): 77-87.

Falkowski, P. G. (1980). Light shade adaptation in marine phytoplankton. New York, NY, Plenum Press.

Falkowski, P. G. (1983). "Light-shade adaptation and vertical mixing of marine phytoplankton: A comparative field study." J. Marine Res. 41: 215-237.

Falkowski, P. G. (1984). "Physiological responses of phytoplankton to natural light regimes." J. Plankton Res. 6(6): 295-307.

Falkowski, P. G. (1984). "Kinetics of adaption to irradiance in Dunaliella tertiolecta." Photosynthetica 18: 62-68.

Falkowski, P. G. (1996). Ocean Productivity Science Plan: Using satellite data to derive primary productivity in the worlds oceans. A Science Plan for the Mission to Earth.

Falkowski, P. G., Z. Dubinsky, et al. (1985). "Growth-irradiance relationships in marine phytoplankton." Limnol. Oceanogr. 30(2): 311-321.

Falkowski, P. G. and J. La Roche (1991). "Acclimation to spectral irradiance in algae." J. Phycol.

Falkowski, P. G. and T. G. Owens (1980). "Light-shade adaptation: two strategies in marine phytoplankton." Plant Physiology 66: 592-595.

Falkowski, P. G. and J. Raven (1997). Aquatic photosynthesis. Malden, MA, Blackwell Science, Inc.

Falkowski, P. G. and C. D. Wirick (1981). "A simulation model of the effects of vertcal mixing on primary productivity." Mar. Biol. 65: 69-75.

Fee, E. J. (1975). "The importance of diurnal variation of photosynthesis vs. light curves to estimates of integral primary production." Verh. Internat. Verein. Limnol. 19: 39-46.

Fee, E. J. (1998). "Revision of: Computer programs for calculating in situ phytoplankton photosynthesis." Can. Tech. Rept. Fisheries and Aquatic Sci. 1740.

Felip, M. and J. Catalan (2000). "The relationship between phytoplankton biovolume and chlorophyll in a deep oligotrophic lake: decoupling in their spatial and temporal maxima." Journal of Plankton Research 22(1): 91-105.

Fileman, T. W., D. W. Pond, et al. (1998). "Vertical profiles of pigments, fatty acids and amino acids: Evidence for undegraded diatomaceous material sedimenting to the deep ocean in the Bellingshausen Sea, Antarctica." Deep-Sea Research Part I-Oceanographic Research Papers 45(2-3): 333-346.
The organic carbon content and biochemical composition of suspended particulate material was investigated at five stations in the marginal ice zone of the Bellingshausen Sea during the austral spring of 1992, Stations, each consisting of profiles of between four and eight depths, were sampled along longitude 85 degrees W from fast ice conditions to open water. Samples were collected using large volume in situ filtration systems. The horizontal and vertical distribution of organic carbon, fatty acids, pigments and amino acids reflected strongly the physical environment and planktonic species composition. Concentrations of total hydrolysable amino acids, total fatty acids and photosynthetic pigments all exhibited marked reductions with depth. At an open water station, significant levels of labile fatty acids (16 :4n - 1 and 20 : 5n - 3) and the xanthophyll fucoxanthin were present at a depth of 3900 m, indicating the sedimentation of undegraded, diatom derived material into the deep ocean. Amino acid, fatty acid and pigment concentrations suggest that degradation rates of particulate material below 500-1000 m were very low. The results show that in some circumstances undegraded material of photosynthetic origin reaches the deep ocean. However, the significance and contribution of this material to the nutrition of deep water pelagic and benthic communities remains to be established. The results are discussed in terms of the transfer of biogenic material from the euphotic zone into the deep ocean and the implications for deep water ecosystems. (C) 1998 Elsevier Science Ltd. All rights reserved.

Fisher, T., T. Berner, et al. (1998). "The kinetics of the photoacclimation response of Nannochloropsis sp. (Eustigmatophyceae): A study of changes in ultrastructure and PSU density." J. Phycol. 34: 818-824.

Flameling, I. A. and J. Kromkamp (1997). "Photoacclimation of Scenedesmus protuberans (Chlorophyceae) to fluctuating irradiances simulating vertical mixing." Journal of Plankton Research 19(8): 1011-1024.

Fookes, C. J. R. and S. W. Jeffrey (1989). "The Structure of Chlorophyll-C3, a Novel Marine Photosynthetic Pigment." Journal of the Chemical Society-Chemical Communications(23): 1827-1828.

Frenette, J. J., S. Demers, et al. (1994). "Mixing, Stratification and the Fate of Primary Production in an Oligotrophic Multibasin Lake System (Quebec, Canada)." Journal of Plankton Research 16(9): 1095-1115.
Impacts of mixing and stratification on the fate of primary production were studied in an oligotrophic lake by comparing the size-distributions of phytoplankton standing stock and production in two basins, only one of which experiences seasonal thermal stratification. In both basins, the phytoplankton was dominated by small cells (pico- and nanoplankton). The contribution of picoplankton to both biomass and production remained relatively constant throughout the season in both basins. Seasonal variations in the size structure of phytoplankton communities do not agree with the paradigm of dominance by small cells during summer stratification and dominance of larger cells during spring and fall mixing events. Nutrient control of productivity through mixing and stratification is unlikely to affect the structure of phytoplankton communities when nutrients (allochthonous) derived from the catchment basin or sediments are in short supply. In such environments, nutrients (autochthonous) are largely derived in the lake through heterotrophic food web processes such as grazing, excretion and decomposition. Maximum rates of production and losses in July and August in both basins are consistent with increased regeneration and may represent a response of larger-sized cells to higher nutrient availability resulting from enhanced grazing on picoplankton. The high correlation between the rates of loss and of potential growth for the phytoplankton community during all sampling periods, and the relative constancy of the picoplankton biomass, leads us to propose a long-term, steady-state equilibrium in the phytoplankton community under the control of grazing by herbivores and/or other loss processes.

Frenette, J. J., S. Demers, et al. (1993). "Lack of Agreement among Models for Estimating the Photosynthetic Parameters." Limnology and Oceanography 38(3): 679-687.
Comparisons were conducted between estimates of photosynthetic capacity (P(max)) and photosynthetic efficiency (alpha) calculated with different models of the photosynthesis vs. irradiance curve. Values computed on the same data sets are different according to the models used. Estimates for P(max) with the exponential and hyperbolic tangent models (without a term for photoinhibition) are in good agreement (4% difference). The same comparison for a shows poor agreement (24% difference between the two models). When a parameter for the intercept is added to the two models, the lack of agreement increases to 8% for P(max) and 46% for alpha. When the mean photosynthetic parameters calculated with the two models are introduced into various published models for calculating primary production, differences in the resulting estimates range between 20 and 133%. Comparing the exponential model with a term for photoinhibition to the hyperbolic tangent model (without a term for photoinhibition) shows a 24% difference in the estimate of alpha. Equations are given for transforming values calculated with the various models.

Frost, T., J. Hurley, et al. (1999). "Assessment of grazing by the freshwater copepod Diaptomus minutus using carotenoid pigments: a caution." Journal of Plankton Research 21(1): 127-145(19).

Furuya, K. (1990). "Subsurface Chlorophyll Maximum in the Tropical and Subtropical Western Pacific-Ocean - Vertical Profiles of Phytoplankton Biomass and Its Relationship with Chlorophyll-a and Particulate Organic-Carbon." Marine Biology 107(3): 529-539.
Vertical distribution of phytoplankton biomass in terms of carbon content (PC) and its relationship with chlorophyll a and particulate organic carbon (POC) were examined together with phytoplankton growth rates in the tropical and subtropical western Pacific in 1979, where a prominent subsurface chlorophyll maximum (SCM) developed between 65 and 150 m. Fluorescence microscopy combined with image analysis was used for measurement of cell volume which was converted to PC. The SCM coincided consistently with subsurface maximum of PC, and the SCM primarily reflected in situ accumulation of phytoplankton biomass. The PC:chlorophyll a ratio decreased with depth; the ratio was 1.8 times, on average, higher in populations at the SCM compared to those near the surface. This increase in relative cellular chlorophyll a along with depth accentuated the magnitude of the SCM. The PC:POC ratio was substantially lower near the surface, 0.17 on average, and increased sharply around the SCM, with a mean value of 0.53. Thus suspended particles around SCM were richer in phytoplankton than those in the upper layers. A major part of PC was contributed by autotrophic eukaryotes both near the surface and at the SCM, and prokaryotic picoplankton comprised a relatively small proportion (6.3 to 14.9%) of PC. The high phytoplankton biomass around the SCM was suggested to be ascribed to in-situ growth of phytoplankton.

Furuya, K. and M. S. Han (2000). "Size and species-specific primary productivity and community structure of phytoplankton in Tokyo Bay." Journal of Plankton Research 22(7): 1221-1235(15).

Gallegos, C. L. and T. Platt (1982). "Phytoplankton production and water motion in surface mixed layers." Deep-Sea Research 29(1a): 65-76.

Ganf, G. G., S. I. Heaney, et al. (1991). "Light-Absorption and Pigment Content in Natural-Populations and Cultures of a Non-Gas Vacuolate Cyanobacterium Oscillatoria- Bourrellyi (= Tychomema-Bourrellyi)." Journal of Plankton Research 13(5): 1101-1121.
Vertical profiles of temperature, the flux density and spectral composition of irradiance and the vertical distribution of Oscillatoria bourrellyi were measured in the North and South Basins of Windermere in the English Lake District. At the population maximum (8-14 m) the photon flux was 0.3-14-mu-mol m-2 s-1 with the waveband 512-580 nm contributing 54-60% of the photosynthetically active irradiance. Samples of O.bourrellyi taken concurrently from 0 and 12 m were analysed to determine the absorption properties of the populations and the phycoerythrin-related fluorescence of individual filaments. The 12 m populations were distinguished from the surface populations by higher beam absorption coefficients at all wavelengths throughout the visible spectrum. These differences were accentuated when the absorption characteristics were calculated using in situ irradiance profiles. The deeper populations consistently absorbed a greater fraction of the available irradiance than the shallow populations. This was due to an overall increase in the total pigment per cell rather than the differential synthesis of phycobiliprotein pigments. These observations were confirmed by both laboratory and field experiments using cultures of O.bourrellyi. In these experiments low white light was sufficient to induce the synthesis of both phycoerythrin and phycocyanin as well as chlorophyll. Mean individual filament fluorescence also distinguished populations from different depths. These measurements further demonstrated that filaments within a population located at a discrete depth have a wide range of fluorescence. This variation increased with decreasing light intensity and suggests that phycoerythrin could be used as a cellular marker to determine the provenance of individual filaments. The benefits of photo-adaptation in O.bourrellyi are analysed in relation to the variable underwater light climate of Windermere, UK. Their ecological significance for this alga during periods of intense but intermittent stratification in a nutrient-limited environment are discussed. The ecological implications of both intra- and inter-specific variations in the absorption properties of phytoplankton are discussed in relation to the use of simple community or populations means as the data entry points for models of photosynthetic production.

GarciaMendoza, E. and H. Maske (1996). "The relationship of solar-stimulated natural fluorescence and primary productivity in Mexican Pacific waters." Limnology and Oceanography 41(8): 1697-1710.
Solar-stimulated natural chlorophyll a fluorescence measured by upwelling radiance in the red spectral band could be a fast and noninvasive method to estimate primary production in aquatic environments if the relationship of primary production to natural fluorescence can be described as a function of easily measured environmental variables. We compared data of natural fluorescence and primary production (C-14 incubation for 2 h) from the California Current and the Gulf of California. The data confirm that the quantum yield ratio of fluorescence to primary production (phi(c):phi(f)) is a function of in situ irradiance, but not of nutrient concentration or temperature, as has been reported in the literature. Published data from the subtropics and tropics and our data yield empirical constants that define the irradiance function of the quantum yield ratio, but variability results from ambiguity of the constant determination caused by high variance of the data. Data from the Antarctic are significantly different from the low latitude data. Below a photosynthetic rate of 300 nmol C m(-3) s(-1) our natural fluorescence data are useful as a proxy of primary production with a correlation coefficient, r(2), of 0.85. Of the unexplained variance (15%), a major portion is due to the C.V. of the primary production method (9.2%). The r(2) value of predicted primary production is similar to other published results, which suggests that without further information about the physiology of the phytoplankton it will be difficult to improve the quality of the primary production estimate.

Gardner, W. D., J. S. Gundersen, et al. (1999). "The role of seasonal and diel changes in mixed-layer depth on carbon and chlorophyll distributions in the Arabian Sea - a comparison with primary production." Deep Sea Research Part II: Topical Studies in Oceanography 46(8): 1833-1858(26).

Geider, R. J., H. L. MacIntyre, et al. (1997). "Dynamic model of phytoplankton growth and acclimation: responses of the balanced growth rate and the chlorophyll a:carbon ratio to light, nutrient-limitation and temperature." Marine ecology progress series 1481/3: 187.

Geider, R. J., H. L. MacIntyre, et al. (1998). "A dynamic regulatory model of phytoplanktonic acclimation to light, nutrients, and temperature." Limnology and Oceanography 43(4): 679-694.

Geider, R. J., B. A. Osborne, et al. (1986). "Growth photosynthesis and maintenance metabolic cost in the diatom Phaeodactylum tricornutum at very low levels." J. Phycol. 22: 39-48.

Gervais, F., T. Hintze, et al. (1999). "An incubator for the simulation of a fluctuating light climate in studies of planktonic primary productivity." International Review of Hydrobiology 84(1): 49-60.
A laboratory system for the quantification of phytoplankton photosynthesis under fluctuating light climate conditions is described. It consists of 2 temperature-controlled incubators with a variable light supply, an algal batch culture in incubation bottles with appropriate stirrers and a set of oxygen electrodes to monitor algal photosynthesis. By the rotation of special grey filters between the incubator and the light source, a regular up and down movement in the water column is simulated in up to 7 parallel bottles. Different ratios of euphotic depth to mixing depth and different velocities can be applied. Simultaneously, 8 bottles can be incubated under constant light. The system is demonstrated in experiments with Chlamydomonas sp. Further possibilities of application are proposed.

Giordano, M., M. Kansiz, et al. (2001). "Fourier Transform Infrared Spectroscopy as a Novel Tool to Investigate Changes in Intracellular Macromolecular Pools in the Marine Microalga Chaetoceros Muellerii (Bacillariophyceae)." Journal of Phycology 37(2): 271-279(9).

Gleitz, M. and D. N. Thomas (1992). "Physiological-Responses of a Small Antarctic Diatom (Chaetoceros Sp) to Simulated Environmental Constraints Associated with Sea-Ice Formation." Marine Ecology-Progress Series 88(2-3): 271-278.
The phvsiological responses of a small unicellular Chaetoceros species, isolated from the Weddell Sea, Antarctica, to changes in temperature, Salinity and irradiance simulating those that occur during new-ice formation were investigated. The combination of increased salinity, increased quantum irradiance and decreased temperature significantly reduced growth and photosynthetic rates compared to the control, although cellular metabolism was not inhibited. The cells retained the capacity to photoacclimate, which was observed in the variations in cellular chlorophyll a concentrations and carbon allocation patterns. In terms of photosynthesis, a doubling of quantum irradiance apparently compensated for the adverse effects of increased salinity and lowered temperature. It is thus hypothesized that at least some species of the late season phytoplankton population survive incorporation into ice and continue to photosynthesize and grow under the extreme conditions encountered during sea-ice formation. This potentially prolonges the Antarctic vegetation period well into late austral autumn and winter, enhancing the total primary production available for higher trophic levels.

Godhantaraman, N. and K. Krishnamurthy (1998). "Experimental studies on food habits of tropical microzooplankton: (prey-predator interrelationship)." Oceanographic Literature Review 45(6): 979-979(1).

Goericke, R. and N. A. Welschmeyer (1992). "Pigment turnover in Thalassiosira weisflogii. II. The 14CO2 labelling kinetics of carotenoids in a marine diatom." J. Phycol. 28: 507-517.

Gong, G. C., J. Chang, et al. (1999). "Estimation of annual primary production in the Kuroshio waters northeast of Taiwan using a photosynthesis-irradiance model." Deep-Sea Research Part I-Oceanographic Research Papers 46(1): 93-108.

Gons, H. J. and M. Rijkeboer (1992). "The True Growth Efficiency of Phytoplankton as Influenced by Light Attenuation and Insolation - Implications of the Photosynthesis-Irradiance Relationship." Hydrobiologia 238: 169-176.
The 'true' growth efficiency (c) relates the light energy absorbed by phytoplankton to the production of biomass corrected for constant energy requirement of maintenance. Continuous culture studies have shown that, at constant incident irradiance, the value of c for both prokaryotic and eukaryotic species is constant. Culture data for the relevant conditions of incident light may be used for directly estimating the growth rate from daily insolation of.optically deep, fully mixed lakes, when the light absorption by the phytoplankton can be established. In order to examine the influence of vertical light attenuation and daily insolation on c, computations were made on a basis of a photosynthesis- irradiance curve of light-limited Oscillatoria limnetica. For steady state growth, the 'true' growth efficiency is linearly related to the areal quantum efficiency of photosynthesis (phi(a)). The computations showed that phi(a) remains constant at fluctuating vertical light attenuation, no matter whether the concentration of tripton or phytoplankton changes. The effect of insolation is great: phi(a) is 0.108 mol O2/E at very low light, but only 0.014 mol O2/E at 400 W M-2 subsurface downward irradiance. The results imply that a c-value obtained from cultures for summer averaged insolation must be corrected: between cloudy and clear days the value may vary by a factor of 2. The 'true' growth efficiency for cultures will decrease by about 10% when the same daily irradiation is dosed sinusoidally instead of constantly.

Gorbunov, M. Y., P. G. Falkowski, et al. (2000). "Measurement of photosynthetic parameters in benthic organisms in situ using a SCUBA-based fast repetition rate fluorometer." Limnology and Oceanography 45(1): 242-245.

Gordon, H. R. and A. Morel (1983). "Remote assessment of ocean color for interpretation of satellite imagery: a review." Springer-Verlag.

Graham, N. J. D., V. E. Wardlaw, et al. (1998). "The significance of algae as trihalomethane precursors." Water Science and Technology 37(2): 83-89(7).

Graham, N. J. D., V. E. Wardlaw, et al. (1998). "Late quaternary climate change in eastern North America - comparisons with model results." Quaternary Science Reviews 17(6): 587-606(20).

Greenler, R. G., N. P. Lasca, et al. (1993). "The Science Bag(Tm) at the University-of-Wisconsin-Milwaukee - a Successful Forum for Science Outreach." American Journal of Physics 61(4): 326-329.
A series of science programs for the public has been running for 19 years with an accumulated attendance of 95 000 people.

Greenler, R. G., N. P. Lasca, et al. (1993). "The Science Bag(Tm) at the University-of-Wisconsin-Milwaukee - a Successful Forum for Science Outreach." American Journal of Physics 61(4): 326-329.
A series of science programs for the public has been running for 19 years with an accumulated attendance of 95 000 people.

Grobbelaar, J. U. (1989). "The Contribution of Phytoplankton Productivity in Turbid Fresh- Waters to Their Trophic Status." Hydrobiologia 173(2): 127-133.

Grobbelaar, J. U. (1990). "Modeling Phytoplankton Productivity in Turbid Waters with Small Euphotic to Mixing Depth Ratios." Journal of Plankton Research 12(5): 923-931.

Grobbelaar, J. U. (1991). "The Influence of Light Dark Cycles in Mixed Algal Cultures on Their Productivity." Bioresource Technology 38(2-3): 189-194.
In mass algal cultures, some form of agitation is usually provided, which amongst others, moves the organisms though an optically dense profile. During this transport, fluctuations in the light energy supply are perceived by the algae, which are of the order of 1 Hz and less. Additional to these variations the cultures are subject to diurnal, seasonal and climatic light variations. It has been suggested that turbulence with the resultant light/dark cycles enhances their productivity. However, turbulence has two major influences on an organism, i.e. it facilitates fluctuating light regimes and decreases the boundary layer which results in an increased exchange rate between the organism and its environment. With the aid of oxygen liberation measurements, the influence of fluctuating light regimes on productivity was measured. No simple relation existed, but no enhancement of productivity could be shown at cycles of 1-0.0038 Hz. Short term physiological changes were found to influence productivity severely.

Grobbelaar, J. U. (1994). "Turbulence in Mass Algal Cultures and the Role of Light-Dark Fluctuations." Journal of Applied Phycology 6(3): 331-335.
In mass algal cultures, some form of agitation is usually provided; among other effects, this moves the organisms though an optically dense profile and provides mixing. During this transport, medium frequency fluctuations in the light energy supply are perceived by the algae, which are of the order of 1 Hz and less. It has been suggested that turbulence with the resultant light/dark cycles of medium frequency enhances productivity. However, turbulence has two major influences in a well mixed system: it facilitates fluctuating light regimes and increases the transfer rates between the growth medium and the cultured organism. An estimation of productivity as oxygen liberation was measured under laminar and turbulent flow rates, and varying light/dark ratios. Increased turbulence, which increased exchange rates of nutrients and metabolites between the cells and their growth medium, together with increased light/dark frequencies, increased productivity and photosynthetic efficiency.

Grobbelaar, J. U. (2000). "Physiological and technological considerations for optimising mass algal cultures." Journal of Applied Phycology 12(3-5): 201-206.
The successful coupling between physiology and technology is central to the success of algal biotechnology. Imperative is a proper understanding of the variables and their impacts on biomass and/or biocompound production. The crux lies in photosynthesis and the capturing of light energy at the optimal rate for eventual maximal photochemistry (biosynthesis). It is in the hands of algal biotechnologists to understand the dynamics and regulatory mechanisms of especially PSII (photosystem II) activity in order to advance this technology further. Biophysical and technological optimisation and design aimed at maximising photon flux capture are some of the avenues that needs be pursued. This needs to be augmented by molecular, biochemical and physiological inputs. Unfortunately detailed systematic analyses of the variables, their interaction and possible synergism have rarely been done. The debate regarding the merits and productivity in closed, either plate or tubular, vertical or horizontal, and open pond reactors need to be resolved. Exciting developments regarding online measurements and feedback control for optimal productivities are part of the solutions and approaches that need to be followed. Multistage systems that not only utilise autotrophic growth and stress components, but also combined autotrophic/heterotrophic systems could provide solutions to specific production requirements. These and other important issues are addressed in the overview. The challenges facing algal biotechnologists and future research needs are also discussed.

Grobbelaar, J. U., B. M. A. Kroon, et al. (1992). "Influence of Medium Frequency Light Dark Cycles of Equal Duration on the Photosynthesis and Respiration of Chlorella- Pyrenoidosa." Hydrobiologia 238: 53-62.
Chlorella pyrenoidosa was grown in three continuous cultures each receiving a different light regime during the light period of a diurnal cycle. Hourly samples taken during the light period were subjected to medium frequency light/dark oscillations of equal duration, ranging from 3 to 240 seconds. The oxygen consumption and production of each sample were measured with an oxygen electrode in a small oxygen chamber. Although the light/dark cycles had little overall influence on photosynthetic activity, the microalgae appeared to adapt to the light regime to which they were subjected. Large differences were found between the maximum chlorophyll-specific production rates (P(max)B), the chlorophyll-specific production rates (P(B)) and the respiration rates between the cultures and treated subsamples. Respiration rates increased during the light period, whilst P(B) either increased, or had a mid light period minimum or maximum. The culture which received an hourly light oscillation during the light period had the highest P(max)B and lowest respiration rates. and it is suggested that these algae react as in nature, whereas either a sinusoidal or a block light pattern is 'unnatural'. The latter light regime is commonly used in laboratory studies.

Grobbelaar, J. U., L. Nedbal, et al. (1995). "Variation in Some Photosynthetic Characteristics of Microalgae Cultured in Outdoor Thin-Layered Sloping Reactors." Journal of Applied Phycology 7(2): 175-184.
In outdoor thin-layer sloping reactors algae are batch cultured and harvested at biomass concentrations of about 15 g (dw) 1(- 1) whereafter a portion is used as inoculum for the next cycle. Light saturation curves of the oxygen evolution (P/I curves) of the algae were measured using diluted aliquots of suspension taken from the reactors. The maximum specific photosynthetic rates (P-max(B)) and the light intensity at the onset of saturated photosynthesis (I-k) decreased whilst the maximum specific photosynthetic efficiency (alpha(B)) increased with an increase in the biomass concentration, during the production cycle. These differences reflect transition from light- to dark-acclimated state of the algae that occurs as a result of an increase of the suspension concentration during the production cycle. During these experiments the thin-layered smooth doping cultures (TLSS, culture depth 5-7 mm) had higher photosynthetic rates per volume than the thin-layered baffled sloping cultures (TLBS, culture depth 5-15 mm). This was ascribed to the higher P-max(B) values of the algae grown in the TLSS cultures, allowing them to utilise high incident irradiancies more effectively. However, the areal productivity of the TLBS was higher than the TLSS indicating a higher photosynthetic efficiency of the TLBS reactors. The specific productivity decreased rapidly with an increase in the biomass concentration, but the yield remained linear during the batch production cycle, even at high areal densities.

Grobbelaar, J. U., L. Nedbal, et al. (1996). "Influence of high frequency light/dark fluctuations on photosynthetic characteristics of microalgae photoacclimated to different light intensities and implications for mass algal cultivation." Journal of Applied Phycology 8(4-5): 335-343.
Oxygen evolution from a Scenedesmus obliquus dominated outdoor culture was followed in a small volume chamber, irradiated either by continuous white light or under light/dark frequencies between 0.05 to 5000 Hz, using arrays of 'high intensity' red light emitting diodes (LED's). By placing neutral density filters in the path of the white light, light saturation curves of the oxygen evolution (P/I curves) were measured using diluted aliquots of algal cultures. The results clearly showed that photosynthetic rates increased exponentially with increasing light/dark frequencies, that a longer dark period in relation to the light period does not necessarily lead to higher photosynthetic rates (efficiencies), and that algae do not acclimate to a specific light/dark frequency. One of the most important factors that influenced photosynthetic rates, either under continuous illumination or intermittent, was whether the algae were dark or light acclimated. Low light/dark frequencies were perceived by the algae as low light conditions, whilst the opposite was true for high frequencies. The light utilisation efficiency in a fluctuating light/dark environment depended on the acclimated state of the algae, the specific frequency of the fluctuations and the duration of the exposure. Since the frequencies determined the 'perceived' quantities of light, dark reactions played an important role in determining the average photosynthetic efficiencies. These results have important implications for algal biotechnology.

Grobbelaar, J. U., C. J. Soeder, et al. (1990). "Modeling Algal Productivity in Large Outdoor Cultures and Waste Treatment Systems." Biomass 21(4): 297-314.

Guerrini, F., M. Cangini, et al. (2000). "Metabolic responses of the diatom Achnanthes brevipes (Bacillariophyceae) to nutrient limitation." J. Phycol. 36(5): 882-a-890.
The diatom Achnanthes brevipes C.A. Ag. was cultured in the presence of limiting concentrations of nitrogen (N) or inorganic phosphate (Pi). Growth, in terms of final yield, was more affected by N limitation than Pi limitation; N limitation had a greater effect also on protein and chlorophyll content. Carbohydrate concentrations increased under both nutrient starvation treatments, but N or Pi limitation had different effects. Total (intracellular plus extracellular) sugar content increased when cells were exposed to both types of nutrient limitation, but the extracellular polysaccharide fraction increased only in the presence of Pi starvation. Analyses were performed to identify the metabolic changes occurring in cells exposed to low phosphate because this was the main condition that affected carbohydrate extrusion. Activities of several enzymes involved in carbohydrate metabolism showed that under Pi limitation there was no activation of alternative reactions that were found to result in Pi liberation, instead of its consumption, in some higher plants and in the green alga Selenastrum minutum Naeg. Collins. Results showed that activities of pyruvate kinase, phosphorylating NAD-dependent 3-phosphate-glyceraldehyde dehydrogenase, and 3-phospho-glycerate kinase were inhibited under Pi-limited conditions compared with control cells, indicating limited glucose catabolism. Activity of uridine diphosphate glucose pyrophosphorylase, a key enzyme for the biosynthesis of the storage compound crysolaminarin, was also partly inhibited in Pi-stressed cells. Our findings suggest that carbohydrate catabolism in A. brevipes is limited under Pi deficiency, whereas extracellular extrusion of carbohydrate is favored.

Guildford, S. J., H. A. Bootsma, et al. (2000). "Phytoplankton nutrient status and mean water column irradiance in Lakes Malawi and Superior." Aquatic Ecosystem Health & Management 3(1): 35-45.

Haffner, G. D., G. P. Harris, et al. (1980). "Physical variability and phytoplankton communites: III. Vertical structure in phytoplankton populations." Arch. Hydrobiol. 89(3): 363-381.

Han, B. P., M. Virtanen, et al. (1999). "Predictors of light-limited growth and competition of phytoplankton in a well-mixed water column." Journal of Theoretical Biology 197(4): 439-450.

Harris, G. P. (1973). "Diel and annual cycles of net plankton photosynthesis in Lake Ontario." Journal of Fisheries Research Board of Canada 30(12, pt. 1): 1179-1787.

Harris, G. P. and J. N. A. Lott (1973). "Light Intensity and photosynthetic rates in phytoplankton." Journal of Fisheries Research Board of Canada 30(12, pt. 1): 1171-1178.

Harris, G. P. and B. B. Piccinin (1980). "Physical variability and phytoplankton communities: IV. Temporal changes in the phytoplankton community of a physically variable lake." Arch. Hydrobiol. 89(4): 447-473.

Hawes, I. (1990). "The effects of light and temperature on photosynthate in Antarctic freshwater phytoplankton." Journal of plankton research 12(3): 513.

Heaney, S. I., M. C. Davey, et al. (1989). "Formation of Sub-Surface Maxima of a Diatom within a Stratified Lake and in a Laboratory Column." Journal of Plankton Research 11(6): 1169-1184.

Heaney, S. I., M. C. Davey, et al. (1989). "Formation of Sub-Surface Maxima of a Diatom within a Stratified Lake and in a Laboratory Column." Journal of Plankton Research 11(6): 1169-1184.

Heaney, S. I., J. E. Parker, et al. (1996). "Interannual variability of algal populations and their influence on lake metabolism." Freshwater Biology 35(3): 561-&.
1. An input-output phosphorus budget is given for Windermere and its two basins based on data available for the late 1980s. The annual areal total phosphorus loading for the whole lake was 1.04 g P m(-2) yr(-1) and for the North and South Basins were 1.08 and 1.70 g P m(-2) yr(-1), respectively. For the whole lake and its South Basin the values were similar to the upper range of critical loads calculated according to the equation of Vollenweider (1976) for the transition between oligotrophy and eutrophy while that for the North Basin (1.08 g P m(-2) yr(-1)) was within this range of critical loadings but towards its lower end. 2. Changes in the quality of summer phytoplankton are described for Windermere, particularly its South Basin, between 1978 and 1989 in relation to the utilization of nitrate-nitrogen (NO3-N) in the epilimnion, deoxygenation of the hypolimnion and the ratio of epilimnetic volume to hypolimnetic volume, E(v)/H-v. The two basins of Windermere with values of E(v)/H-v of 0.79 (South Basin) and 0.50 (North Basin) have contrasting conditions of summer deoxygenation. The shallower South Basin shows marked interannual variability in the development of hypolimnetic anoxia. Years with large hypolimnetic anoxia during autumn are correlated with the production during summer of large populations of the poorly grazed blue-green alga Oscillatoria bourrellyi and exhaustion of NO3-N in the upper layers. During years when anoxia does not develop the summer phytoplankton consists of small easily grazed algae or larger ones subject to parasitic epidemics. The deeper North Basin never becomes anoxic even though it can contain similar sized populations of O. bourrellyi to the South Basin. 3. A possible explanation of the between basin and, for the South Basin, between year variation of utilization of NO3-N and level of hypolimnetic deoxygenation is that algal quality can determine lake metabolism dependent upon lake or basin morphology. Poorly grazed large forms such as O. bourrellyi act as sinks for NO3- N. On sedimentation such populations act as a 'short circuit' mechanism descending into deeper layers in sufficient quantities to cause anoxia. Other species subject to crustacean or microbial grazing are mineralized in the epilimnion with little sedimentation to the deeper waters. Subsequent recycling of nitrogen as NH4-N takes place in the upper layers or thermocline which is more readily taken up by subsequent production. The influence of such 'short circuit' mechanisms is reduced in deep lakes and exacerbated in shallow ones. 4. The success of species such as O. bourrellyi is dependent upon a sufficient inoculum, an adequate supply of nutrients and the depth of intermittent mixing. The importance of these factors in regulating presence and timing of summer populations is illustrated and discussed.

Heaney, S. I., J. E. Parker, et al. (1996). "Interannual variability of algal populations and their influence on lake metabolism." Freshwater Biology 35(3): 561-&.
1. An input-output phosphorus budget is given for Windermere and its two basins based on data available for the late 1980s. The annual areal total phosphorus loading for the whole lake was 1.04 g P m(-2) yr(-1) and for the North and South Basins were 1.08 and 1.70 g P m(-2) yr(-1), respectively. For the whole lake and its South Basin the values were similar to the upper range of critical loads calculated according to the equation of Vollenweider (1976) for the transition between oligotrophy and eutrophy while that for the North Basin (1.08 g P m(-2) yr(-1)) was within this range of critical loadings but towards its lower end. 2. Changes in the quality of summer phytoplankton are described for Windermere, particularly its South Basin, between 1978 and 1989 in relation to the utilization of nitrate-nitrogen (NO3-N) in the epilimnion, deoxygenation of the hypolimnion and the ratio of epilimnetic volume to hypolimnetic volume, E(v)/H-v. The two basins of Windermere with values of E(v)/H-v of 0.79 (South Basin) and 0.50 (North Basin) have contrasting conditions of summer deoxygenation. The shallower South Basin shows marked interannual variability in the development of hypolimnetic anoxia. Years with large hypolimnetic anoxia during autumn are correlated with the production during summer of large populations of the poorly grazed blue-green alga Oscillatoria bourrellyi and exhaustion of NO3-N in the upper layers. During years when anoxia does not develop the summer phytoplankton consists of small easily grazed algae or larger ones subject to parasitic epidemics. The deeper North Basin never becomes anoxic even though it can contain similar sized populations of O. bourrellyi to the South Basin. 3. A possible explanation of the between basin and, for the South Basin, between year variation of utilization of NO3-N and level of hypolimnetic deoxygenation is that algal quality can determine lake metabolism dependent upon lake or basin morphology. Poorly grazed large forms such as O. bourrellyi act as sinks for NO3- N. On sedimentation such populations act as a 'short circuit' mechanism descending into deeper layers in sufficient quantities to cause anoxia. Other species subject to crustacean or microbial grazing are mineralized in the epilimnion with little sedimentation to the deeper waters. Subsequent recycling of nitrogen as NH4-N takes place in the upper layers or thermocline which is more readily taken up by subsequent production. The influence of such 'short circuit' mechanisms is reduced in deep lakes and exacerbated in shallow ones. 4. The success of species such as O. bourrellyi is dependent upon a sufficient inoculum, an adequate supply of nutrients and the depth of intermittent mixing. The importance of these factors in regulating presence and timing of summer populations is illustrated and discussed.

Hess, R. W. and M. A. Herkommer (1993). "General principles, efficient approaches to computer contour mapping." Earth Observation Magazine(April): 46-49.

heyman, U., G. Ekbohm, et al. (1982). "The precision of abundance estimates of plankton from composite samples." Water Res. Vol. 16: 1367-1370.

Hinga, K., M. Arthur, et al. (1994). "Carbon isotope fractionation by marine phytoplankton in culture: The effects of CO2 concentration, pH, temperature, and species." Global biogeochemical cycles 8(1): 91.

Hodgson, D. A., S. W. Wright, et al. (1997). "Mass spectrometry and reverse phase HPLC techniques for the identification of degraded fossil pigments in lake sediments and their application in palaeolimnology." Journal of Paleolimnology 18(4): 335-350.
Accurate identification of fossil pigments is essential if they are to be used as biomarker compounds in palaeolimnological studies. In recent years High Performance Liquid Chromatography (HPLC) has greatly enhanced the efficiency with which fossil pigments can be characterised and quantified. Using HPLC,undegraded pigments are typically identified through retention times, absorbance spectra and co-chromatography with authentic reference standards. However, lake sediments may also contain degraded pigments for which there are often no standards, and which may be difficult to identify using HPLC alone. In this study, we submitted HPLC fractions of fossil pigments and pigment derivatives collected from a meromictic lake in south west Tasmania, to a combination of Mass Spectrometry (MS) techniques including Electron Impact (EI) and static Liquid Secondary Ion MS (LSIMS) to identify their molecular ion characteristics and organic chemical composition. Mass Spectrometry permitted the detection of specific mass ions which were used to verify the identity of pigments and their derivatives. These included five carotenoids, chlorophyll a and derivatives, three previously described bacteriochlorophyll c derivatives with molecular weights of 770, 784, and 802, and two undescribed derivatives of bacteriochlorophyll c with molecular weights of 766 and 788. With these improved identifications we speculate on the pathways and modes of pigment degradation in the lake and asses the value of the degraded pigments as biomarkers. The use of MS permitted the identification of a greater number of signature pigments of algal and bacterial communities thus increasing the palaeolimnological value of the sediments. These methods are best applied in fossil pigment studies where there are a large number of unknown pigments and pigment degradation products, and where there are no authentic standards for co- chromatography Practical suggestions for pigment MS are included in the discussion.

Hoepffner, N., B. Sturm, et al. (1999). "Depth-integrated primary production in the eastern tropical and subtropical North Atlantic basin from ocean colour imagery." International Journal of Remote Sensing 20(7): 1435-1456.

Hoffman, B. and H. Senger (1988). "Kinetics of photosynthesis adaptation in Scenedesmus obliquus to change in irradiance and light quality." Photochem. Photobiol. 47: 737-739.

Holfeld, H. (2000). "Infection of the single-celled diatom Stephanodiscus alpinus by the chytrid Zygorhizidium: Parasite distribution within host population, changes in host cell size, and host-parasite size relationship." Limnology and Oceanography 45(6): 1440-1444.
An epidemic caused by a Zygorhizidium species infecting the single-celled planktonic centric diatom Stephanodiscus alpinus was analyzed for parasite distribution within the host population, final parasite size relative to host cell size, and size changes of infected and uninfected S. alpinus cells. Infections in the lake occurred at random within the whole host population. There was no evidence for aggregated or even distribution of the parasite individuals, indicating that the infections occur independently of each other. In enclosures in which light was enhanced compared to the lake, there tended to be an even parasite distribution within the host population, irrespective of whether plant nutrients were added. This suggests that infected host cells were negatively selected by the parasite zoospores under these conditions. Final parasite sporangium size and host cell size were positively correlated. Thus, parasite fecundity was limited by host cell size. Infected S. alpinus cells tended to be larger than uninfected cells, and the mean size of host cells within the population decreased during the epidemic. This might be due to selective infection of larger host cells or to the peculiar mode of cell division in diatoms.

Holfeld, H. (2000). "Relative abundance, rate of increase, and fungal infections of freshwater phytoplankton." Journal of Plankton Research 22(5): 987-995.
Fungal infections of seven species of phytoplankton were examined in relation to the host species' exponential rate of net increase, and to their proportional contribution to the total phytoplankton biovolume. Infections were observed to increase at biovolume proportions of the host species of as low as 1%. In most algal species, infected cells were always found at higher proportions, with the exception of Stephanodiscus rotula and Fragilaria crotonensis. In these two species, high proportions of biovolume were reached without any evidence of infected cells. The increase in infected cells was usually associated with a growing host population, whereas peak and decreasing densities of infected cells were usually observed when host populations were declining. The results show that the fungal parasites can exist on their host population even if it comprises only a small fraction of the total phytoplankton biovolume, and that the parasites become evident while the host population is still increasing.

Hombeck, M. and W. Boland (1998). "Biosynthesis of the Algal Pheromone Fucoserratene by the Freshwater Diatom Asterionella formosa (Bacillariophyceae)." Tetrahedron 54(37): 11033-11042(10).

Huisman, J. (1999). "Population dynamics of light-limited phytoplankton: Microcosm experiments." Ecology 80(1): 202-210.
This paper investigates the extent to which the predictions of an elementary model for light-limited growth are matched by laboratory experiments with light-limited phytoplankton. The model and experiments link the population dynamics of phytoplankton species with changes in the light gradient caused by phytoplankton shading. The model predicts that a phytoplankton population should continue to grow until, at steady state, the light intensity at the bottom of the water column equals its critical light intensity. The experimental results were in good agreement with the theoretical predictions: (1) the steady-state population density increased with an increase of the incident light intensity, (2) the steady-state population density (per unit volume) was inversely proportional to mixing depth, (3) the steady-state population size (per unit area) decreased linearly with mixing depth, (4) the critical light intensity decreased with an increase of the incident light intensity, (5) the critical light intensity was approximately the same at each mixing depth, and (6) the time courses predicted by the model were in line with the observed time courses of population density and light penetration. Implications for phytoplankton ecology and aquatic production biology are discussed.

Huisman, J., R. R. Jonker, et al. (1999). "Competition for light between phytoplankton species: Experimental tests of mechanistic theory." Ecology 80(1): 211-222.
According to recent competition theory, the population dynamics of phytoplankton species in monoculture can be used to make a priori predictions of the dynamics and outcome of competition for light. The species with lowest "critical light intensity" should be the superior light competitor. To test this theory, we ran monoculture experiments and competition experiments with two green algae (Chlorella vulgaris and Scenedesmus protuberans) and two cyanobacteria (Aphanizomenon pos-aquae and a Microcystis strain) in light-limited continuous cultures. We used the monoculture experiments to estimate the critical light intensities of the species. Scenedesmus had by far the highest critical light intensity. The critical light intensities of Chlorella, Aphanizomenon, and Microcystis were rather similar. According to observation, Aphanizomenon had a slightly lower critical light intensity than Chlorella and Microcystis. However, according to a model tit to the monoculture experiments, Chlorella had a slightly lower critical light intensity than Microcystis, which in turn had a slightly lower critical light intensity than Aphanizomenon. These subtle differences between observed and fitted critical light intensities could be attributed to differences in the light absorption spectra of the species. The competition experiments were all consistent with the competitive ordering of the species according to the fitted critical light intensities: Chlorella displaced all three other species. Microcystis displaced both Aphanizomenon and Scenedesmus, and Aphanizomenon only displaced Scenedesmus. Not only the final outcomes, but also the time courses of competition predicted by the theory, were in excellent agreement with the experimental results for nearly all species combinations.

Huisman, J. and F. J. Weissing (1995). "Competition for nutrients and light among phytoplankton species in a mixed water column: Theoretical studies." Water Science and Technology 32(4): 143-147.
A brief overview is given of modelling studies that aim to analyse the effects of nutrient and light limitations on the development of phytoplankton communities and lead to a qualitative understanding of the competitive interactions involved.

Ibelings, B. W., B. M. A. Kroon, et al. (1994). "Acclimation of photosystem II in a cyanobacterium and an eukaryotic green-alga to high and fluctuating photosynthetic photon flux densities, simulating light regimes induced by mixing in lakes." New Phytol. 128: 407-424.

Imberger, J., Ed. (1998). Physical processes in lakes and oceans. Coastal and Estuarine Studies. Washington, D. C., American Geophysical Union.

Interlandi, S. J., S. S. Kilham, et al. (1999). "Responses of phytoplankton to varied resource availability in large lakes of the Greater Yellowstone Ecosystem." Limnology and Oceanography 44(3): 668-682.
We assessed phytoplankton dynamics in three lakes in the Greater Yellowstone Ecosystem to better understand the connections between changing environmental conditions and aquatic communities. This work primarily describes the connections between resource availability and phytoplankton seasonal succession in these lakes. We hypothesized that algal species efficient at utilizing a given resource (including N, P, Si, and light) would be correlated with low relative concentrations of those resources. The lakes generally exhibited moderate resource limitation, which is characteristic of lakes in subalpine and subarctic regions. Although in proximity, the lakes all exhibited different resource relationships: Lewis Lake was most P limited, Jackson Lake was most N limited, and Yellowstone Lake exhibited a moderate degree of N limitation along with periodic Si limitation. Mixing depths and light penetration were also variable among lakes. In 1996, spring diatom biomass was dominated by Stephanodiscus minutulus, Asterionella formosa, Aulacoseira subarctica, and Synedra sp. Relative abundances and dominance varied among the lakes. A. formosa and Synedra sp. abundances were positively correlated with total N:total P (TN:TP) levels in an analysis of data from all three lakes. A. subarctica was negatively correlated with TN:TP and all light: nutrient ratios. Species exhibiting late season maxima included Cyclotella bodanica, Fragilaria crotonensis, and Stephanodiscus niagarae. C. bodanica abundances corresponded to high- light/low-N situations, whereas S, niagarae maxima were found in high-TN: TP/low-light conditions. F. crotonensis abundances were most strongly positively correlated with total Si:TP and TN:TP. Environmental correlations were generally in good agreement with the measured physiological requirements of these species. Additionally, local population maxima of major species of diatoms never coincided.

Introduction, G. (1989). Standard Methods for the Examination of Water and Wastewater. Washington, DC, American Public Health Association.

Iriarte, A. and D. A. Purdie (1993). "Photosynthesis and Growth-Response of the Oceanic Picoplankter Pycnococcus-Provasolii Guillard (Clone Omega-48-23) (Chlorophyta) to Variations in Irradiance, Photoperiod and Temperature." Journal of Experimental Marine Biology and Ecology 168(2): 239-257.
The growth, photosynthesis and respiration rates of the green picoplanktonic algae Pycnococcus provasolii Guillard were measured as a function of irradiance, temperature and photoperiod. The algae showed positive photoadaptation to low irradiance and from an analysis of the photosynthesis versus irradiance curves, it is suggested that this is achieved mainly by increasing the size of the photosynthetic units. In accordance with this conclusion, chlorophyll b to a ratios increased with decreasing photon flux density. The algae further compensated for low light energy supply by reducing the rates of respiration. Values of the initial slope of the growth versus irradiance curve were higher than average (0.0016-0.0022 h-1 (muEm-2 . s-1)-1 at 20-degrees-C). It is thus concluded that P. provasolii Guillard is a well suited organism to grow at sites of low irradiance and this may explain its success in colonizing the pycnocline area of stratified oceanic waters. This capacity, however, was not accompanied by a reduced ability to photosynthesize at high irradiances. A 24 h light regime did not seem harmful to P. provasolii Guillard, however, light energy was utilized less efficiently under 24 h than under 12:12 h photoperiod. Values of Q10 for P(max) and mu(max) were in the region of 2.

Jeffrey, S. W. and G. F. Humphrey (1975). "New spectrophotometric equations for determining chlorophylls a,b,c1 + c2 in higher plants, algae and natural phytoplankton." Biochem. Physiol. Pflanzen. Bd. 167: 191-194.

Jeffrey, S. W., R. F. C. Mantoura, et al. (1997). Phytoplankton pigments in oceanography. Paris, United Nations Educational, Scientific and Cultural Organization.

Jeffrey, S. W., M. Vesk, et al. (1997). "Phytoplankton pigments: windows into the pastures of the sea." Nature & Resources 33(2): 14-29.
The phytoplankton are the microscopic algae that make up the floating pastures of the world's oceans (phyton = plant; planktos = wandering). They provide the food base which supports, either directly or indirectly, the entire animal population of the open sea, and they contribute significantly to climatic processes. In contrast to the well-known diatoms and dinoflagellates, many other groups have only been detected in the last few decades through such techniques as ship-board cell-flow cytometry, delicate preservation techniques and electron microscopy. Another driving force in promoting scientific understanding of phytoplankton has been the development of pigment methods in oceanography, a topic of long-term concern to UNESCO and the Scientific Committee for Oceanic Research.

Jeffrey, S. W., S. W. Wright, et al. (1999). "Recent advances in HPLC pigment analysis of phytoplankton." Marine and Freshwater Research 50(8): 879-896.
Analysis of phytoplankton pigments is central to studies of marine ecology and climate research. This paper summarizes milestones in the development of methods of pigment analysis, and shows the use of HPLC technology in their verification. New advances in HPLC methods are discussed, with key developments being the use of polymeric C-18 and monomeric C-8 columns and pyridine as solvent modifier. These have allowed the resolution of divinyl chlorophylls a and b, and the discovery of new chlorophyll c pigments (both polar and non-polar) and new 4- keto fucoxanthin derivatives. The taxonomic value of pigments and pigment suites is examined. Methods of interpreting the percentage of algal types from field measurements of pigment ratios through the use of computer algorithms are discussed. Finally, prospects for future development are suggested.

Jerome, J. H., R. P. Bukata, et al. (1988). "Utilizing the components of vector irradiance to estimate the scalar irradiance in natural waters." Appl. Opt. 27: 4012-4018.

Johnsen, G. and E. Sakshaug (1996). "Light Harvesting in bloom-forming marine phytoplankton: Species-specificity and photoacclimation." Scientia Marina 60: 47-56.

Johnson, Z., M. L. Landry, et al. (1999). "Energetics and growth kinetics of a deep Prochlorococcus spp. population in the Arabian Sea." Deep-Sea Research Part Ii-Topical Studies in Oceanography 46(8-9): 1719-1743.

Jones, R. C. (1998). "Seasonal and spatial patterns in phytoplankton photosynthetic parameters in a tidal freshwater river." Hydrobiologia 364: 199-208.
The photosynthetic response to irradiance was quantified for phytoplankton from the tidal freshwater Potomac River biweekly to monthly over a period of six years. Samples were collected from two shallow embayments and portions of the deeper river mainstem. Photosynthetic rate was measured in the laboratory at in situ temperature over a range of irradiance levels and photosynthetic parameters were calculated using nonlinear regression. p(max)(B), the maximum photosynthetic rate standardized to chlorophyll a, increased with temperature up to 25 degrees C with a Q(10) of 2.02. Above 25 degrees C, p(max)(B) essentially constant with temperature. Lesser correlation between p(max)(B) and ambient irradiance could be explained by the correlation of irradiance with temperature. alpha, the slope of the P-I curve at low light, was correlated with both ambient irradiance and temperature. Highest alpha values were found in late summer when high temperature and intermediate ambient irradiance were observed. Spring and early summer were characterized by low alpha. Despite low light penetration, I-k and alpha values were indicative of sun limitation possibly due to intermittent high light levels experienced during mixing. I-k showed a clear seasonal trend directly related to days from summer solstice. Spatial patterns were minimal except that I-k was consistently lower in one shallow embayment than in the other two areas. Seasonal patterns in photosynthetic parameters corresponded roughly to changes from a spring diatom population to summer cyanobacterial assemblage.

Juttner, I., J. Lintelmann, et al. (1997). "The acidification of the Herrenwieser See, Black Forest, Germany, before and during industrialisation." Water Research 31(5): 1194-1206(13).

Keller, A. A. (1988). "An Empirical-Model of Primary Productivity (C-14) Using Mesocosm Data Along a Nutrient Gradient." Journal of Plankton Research 10(4): 813-834.

Keller, A. A. (1988). "Estimating Phytoplankton Productivity from Light Availability and Biomass in the Merl Mesocosms and Narragansett Bay." Marine Ecology-Progress Series 45(1-2): 159-168.

Keller, A. A., C. A. Oviatt, et al. (1999). "Predicted impacts of elevated temperature on the magnitude of the winter-spring phytoplankton bloom in temperate coastal waters: A mesocosm study." Limnology and oceanography 44(2): 344.

Kelly, C. A., E. Fee, et al. (2001). "Natural variability of carbon dioxide and net epilimnetic production in the surface waters of boreal lakes of different sizes." Limnology and Oceanography 46(5): 1054-1064.
The variability of surface water carbon dioxide concentration, or partial pressure (pCO(2)) was studied in 11 lakes of greatly varying size (2.4 ha up to 8 million ha) in Northwest Ontario, Canada. Six of these lakes were chosen to be as similar as possible in all respects except surface area (the Northwest Ontario Lake Size Series [NOLSS], which range from 88 to 35,000 ha). Spatial and temporal variability of pCO(2) within a single lake was no greater in the larger lakes than in the smaller lakes. Interannual variability was significant and synchronous, which indicates that weather patterns were important and affected the different lakes within the region in a similar manner. However, annual pCO(2) averages were not related to annual differences in planktonic photosynthetic activity, measured by (CO2)-C-14 fixation. In the six NOLSS lakes, there was not a significant relationship of average pCO(2) with lake size. For all 11 lakes, however, there was a significant negative correlation of pCO(2) with lake size, which was likely due to several characteristics of the very small and very large lakes that covaried with size. The larger lakes were deeper and had longer water residence times and lower DOC, which suggests lower CO2 production from allochthonous organic carbon inputs. Also, the ratio of epilimnetic sediment area/epilimnetic volume (A(e)V(e)) was smaller in the larger lakes, which likely resulted in lower rates of recycling of fixed carbon to CO2 during summer stratification.

Kelly, J. R. and P. H. Doering (1997). "Monitoring and modeling primary production in coastal waters: Studies in Massachusetts Bay 1992-1994." Marine Ecology-Progress Series 148(1-3): 155-168.
During 1992-1994, we made shipboard incubations suitable for determining rates of primary production in water from Boston Harbor, Massachusetts Bay, and Cape Cod Bay (Massachusetts, USA). These measurements were part of an extensive baseline monitoring program to characterize water quality prior to diversion of effluent from Boston Harbor directly into Massachusetts Bay via a submarine outfall diffuser; Production (P) was measured using whole-water samples exposed to irradiance (I) levels from similar to 5 to 2000 mu E m(-2) s(- 1). P-I incubations were performed on 6 surveys a year, spaced to capture principal features of the annual production cycle. The number of stations and depths examined varied between years. There were 10 stations and 2 depths sampled in 1992- 1993. In 1994, we performed in-depth studies at 2 stations (Boston Harbor's edge and western Massachusetts Bay) by sampling 4 depths. Using depth-intensive 1994 data a simple empirical regression model, using information on chlorophyll biomass, incident daily light, and the depth of the photic zone, predicted integrated primary production rates derived from P-I incubations. The regression model was virtually the same as described for other coastal waters, giving confidence in general use of the model as an extrapolation tool. Using the 1994-based empirical model, we obtained favorable comparisons with production rates modeled from 1992-1993 P-I incubations. Combining the regression model with data on chlorophyll, Light, and the photic zone collected on frequent hydrographic surveys (up to 16 yr(-1)), annual primary production was estimated for 1992-1994. Primary production in an intensively studied region of western Massachusetts Bay (21 hydrographic profile stations in an area similar to 100 km(2)) ranged from 386 to 468 g C m(- 2) yr(-1). For a station at the edge of Boston Harbor near Deer Island extrapolations suggested production rates of 263 to 546 g C m(-2) yr(-1). Based on 2 stations in central Cape Cod Bay (1992-1993 only), model extrapolations suggested an annual production of 527 to 613 g C m(-2) yr(-1). Analyses using incubation and modeling results suggested that production variability was strongly related to fluctuations in incident irradiance, especially at daily to seasonal time scales. Chlorophyll variability secondarily influenced production, especially at seasonal to annual time scales. Finally, we provide a case where equivalent production was achieved in environments with contrasting water quality (nutrient and chlorophyll concentrations) because of variations in the depth of the photic zone (controlled by both chlorophyll and non- chlorophyll turbidity). Comparative analyses showed that our study estimates of primary production were consistent with the literature on nutrient-rich shelf environments. In conclusion, our study validated an empirical modeling approach to determining primary production in coastal marine waters.

Kim, D. S. and Y. Watanabe (1993). "The Effect of Long-Wave Ultraviolet-Radiation (Uv-a) on the Photosynthetic Activity of Natural-Population of Fresh-Water Phytoplankton." Ecological Research 8(2): 225-234.
The effect of ultraviolet radiation on diel changes and depth profiles of phytoplankton photosynthesis was studied in four temperate freshwater lakes. Photosynthetic oxygen production was determined by incubating lake water in light and dark bottles under various weather conditions. Half the light bottles were wrapped with sheets of vinyl chloride film to exclude light with wavelengths shorter than 400 nm. The inhibition of photosynthesis due to UV-A (320-400 nm) was observed during most of the daytime and was very strong around noon on both sunny and cloudy days. On sunny days, when the surface waters of the highly eutrophic Lake Suwa and Senzoku Pond were dominated by dense Microcystis populations, cumulative daily production at the surface, estimated from the incubation of bottles from which UV-A was excluded by the vinyl film, were about double the rates obtained from glass bottles in which UV-A was present. The UV-A inhibition was detected from the surface to ca 20 cm depth in hypereutrophic lakes and at depths greater than 50 cm in mesotrophic lakes. Analysis of the photosynthesis-irradiance (P-I) relationship obtained in the present study shows beta, a parameter that describes photo- inhibition, is higher in the presence of UV-A than in its absence. This indicates that UV-A is the major cause of photo- inhibition of phytoplankton photosynthesis.

Kim, D. S. and Y. Watanabe (1994). "Inhibition of Growth and Photosynthesis of Fresh-Water Phytoplankton by Ultraviolet-a (Uva) Radiation and Subsequent Recovery from Stress." Journal of Plankton Research 16(12): 1645-1654.
The effect of ultraviolet A (UVA) on growth and photosynthetic rate was studied in diatoms (Melosira spp.) of the phytoplankton of a eutrophic lake and a cultured green alga Chlorella ellipsoidea. The cells were incubated under photosynthetically active radiation (PAR) (-UVA) or PAR + UVA conditions (+UVA). Growth of C.ellipsoidea was retarded under +UVA, as shown by an increase in the lag period, but the rate of exponential growth was almost the same in + and -UVA conditions. The photosynthetic rate was depressed markedly by UVA in Chlorella cells grown under -UVA. In contrast, cells grown in +UVA showed only slight inhibition by UVA and after exposure to UVA for 6 days there was no inhibition. During the growth experiment, the cellular chlorophyll a content was higher in +UVA than -UVA grown cells. A similar effect was observed in diatoms from the eutrophic Lake Suwa. In vivo fluorescence with (F-a) and without 3-(3,4-dichlorophenyl)-1,1- dimethyl urea (DCMU) (F-b) and the photosynthetic rate were measured for C.ellipsoidea and the diatoms for 5 h under + and -UVA conditions. Soon after C.ellipsoidea had been subjected to +UVA, F-b and F-a - F-b decreased quickly and reached minima after 40 min and 1 h, respectively. The suppressed in vivo fluorescence resumed and full recovery was achieved after 4 h. This suggests that reactivation of the photosystem is acquired under prolonged exposure to UVA. A similar shift of F-a - F-b, but no change in F-b, was found in diatoms by exposure to UVA. Changes in photosynthetic oxygen evolution by C.ellipsoidea under +UVA were similar to changes in F-a - F-b. Degradation of chlorophyll a extracted in methanol was enhanced by UVA. The rate of degradation by UVA was independent of temperature from 15 to 34 degrees C, suggesting a photochemical reaction. The results indicate that C.ellipsoidea and Melosira spp. acclimatize to prolonged UVA exposure by reactivation of the photosystem and enhanced cellular chlorophyll a synthesis. The ecological importance of these results to phytoplankton productivity in natural aquatic environments is discussed.

Kinkade, C., J. Marra, et al. (1997). "Monsoonal differences in phytoplankton biomass and production in the Indonesian Seas: tracing vertical mixing using temperature." Deep-sea research. Part I, Oceanographic research papers 44(4): 581.

Kirby, K. N. Advanced data analysis with SYSTAT. Williams College, Van Nostrand Reinhold, New York.

Kirk, J. T. O. (1984). "Dependence of relationship between inherent and apparent optical properties of water solar altitude." Limnology and Oceanography 29: 350-356.

Kirk, J. T. O. (1991). "Volume scattering function, average cosines and the underwater light field." Limnology and Oceanography 36: 455-467.

Kirk, J. T. O. (1996). Light and Photosynthesis in Aquatic Ecosystems. New York, Cambridge Univ. Press.

Kirkpartick, G. J., T. B. Curtin, et al. (1990). "Measurement of photosynthetic response to euphotic zone physical forcing." Oceanography 3(April): 18-22.

Kolmakov, V. I., N. A. Gaevskii, et al. (1999). "Diurnal dynamics of vertical distribution of diatoms at different levels of solar radiation." Russian Journal of Ecology 30(4): 230-233.
Diurnal changes in the vertical distribution of diatoms (their abundance and content of chlorophyll a) at different levels of insolation were investigated. The cells of seamless colonial pennate diatoms were shown to be capable of photoinduced diurnal vertical migrations. The existence of an "active" mechanism controlling vertical migrations in Asterionella formosa Hass is proposed.

Kotzabasis, K., S. Romer, et al. (1990). "Temperature dependent reduction of protochlorophyllide in darkness followed by the assembly of active photosystems in pigment mutant C-2A' of Scenedesmus obliquus." Physiologia plantarum 78(4): 635.

Kozitskaya, V. N. (1992). "Effect of temperature on growth and reproduction of algae with different pigment systems." Hydrobiological journal 28(1): 103.

Krivtsov, V., E. Bellinger, et al. (2000). "Incorporation of the intracellular elemental correlation pattern into simulation models of phytoplankton uptake and population dynamics." Journal of Applied Phycology 12(3-5): 453-459.
Compelling evidence of complex statistical relationships among various elements contained within phytoplankton cells has traditionally been ignored in models of algal nutrient uptake and population dynamics. Here we present a new approach, incorporating a phytoplankton intracellular elemental correlation pattern into the existing dynamic simulation model of a freshwater lake. Within this approach, uptake and cycling of elements that are likely to become limiting during the simulation period are described by ordinary differential equations. Dynamics of nutrients that are unlikely to become limiting are described either by differential equations or, when more practicable, by multiple regressions on environmental variables and cell quotas of other elements. This allows an easy simultaneous consideration of a wide range of elements. The model adopting the described approach was tested on a data set for Rostherne Mere, Cheshire, UK. It showed a good fit between observations and simulations for all considered variables, including the population dynamics of Ceratium hirundinella and Microcystis aeruginosa, the outcome of interspecific competition and changes in concentrations within algal cells and in the surrounding lake water. The approach could easily be implemented in models of bioreactors, chemostat experiments and aquatic ecosystems.

Krivtsov, V., E. Bellinger, et al. (1998). "Application of SEM XRMA data to lake ecosystem modelling." Ecological Modelling 113(1): 95-123(29).

Krivtsov, V., E. G. Bellinger, et al. (2000). "Changes in the elemental composition of Asterionella formosa during the diatom spring bloom." Journal of Plankton Research 22(1): 169-184(16).

Kromkamp, J. and M. Limbeek (1993). "Effect of short-term variation in irradiance on light harvesting and photosynthesis of the marine diatom Skeletonema costatum: a laboratory study simulating vertical mixing." J. Gen. Microbiol. 139: 2277-2284.

Kroon, B. M. A., M. Latasa, et al. (1992). "The effect of dynamic light regimes on Chlorella. I. Pigments and cross-sections." Hydrobiologia 238: 71-79.

Kroon, B. M. A., M. Latasa, et al. (1992). "An algal cyclostat with computer controlled light regime." Hydrobiologia 238: 63-71.

Kudela, R. M. and R. C. Dugdale (2000). "Nutrient regulation of phytoplankton productivity in Monterey Bay, California." Deep Sea Research Part II: Topical Studies in Oceanography 47(5): 1023-1053(31).

Kudo, I., M. Miyamoto, et al. (2000). "Combined effects of temperature and iron on the growth and physiology of the marine diatom Phaeodactylum tricornutum (Bacillariophyceae)." J. Phycol. 36(6): 1096-1102.
Phaeodactylum tricornutum Bohlin (Bacillariophyceae) was maintained in exponential growth under Fe-replete and stressed conditions over a range of temperatures from 5 to 30 C. The maximum growth rate (GR) was observed at 20 C (optimal temperature) for Fe-replete and -stressed cells. There was a gradual decrease in the GR decreasing temperatures below the optimum temperature; however, the growth rate dropped sharply as temperature increased above the optimum temperature. Fe-stressed cells grew at half the growth rate of Fe-replete cells at 20 C, whereas this difference became larger at lower temperatures. The change in metabolic activities showed a similar pattern to the change in growth rate temperature aside from their optimum temperature. Nitrate reductase activity (NRA) and respiratory electron transport system activity (ETS) per cell were maximal between 15 and 20 C, whereas cell-specific photosynthetic rate (Pcell) was maximal at 20 C for Fe-replete cells. These metabolic activities were influenced by Fe deficiency, which is consistent with the theoretical prediction that these activities should have an Fe dependency. The degree of influence of Fe deficiency, however, was different for the four metabolic activities studied: NRA > Pcell > ETS = GR. NRA in Fe-stressed cells was only 10% of that in Fe-replete cells at the same temperature. These results suggest that cells would have different Fe requirements for each metabolic pathway or that the priority of Fe supply to each metabolic reaction is related to Fe nutrition. In contrast, the order of influence of decreasing the temperature from the optimum temperature was ETS > Pcell > NRA > GR. For NRA, the observed temperature dependency could not be accounted for by the temperature dependency of the enzyme reaction rate itself that was almost constant with temperature, suggesting that production of the enzyme would be temperature dependent. For ETS, both the enzyme reactivity and the amount of enzyme accounted for the dependency. This is the first report to demonstrate the combined effects of Fe and temperature on three important metabolic activities (NRA, Pcell, and ETS) and to determine which activity is affected the most by a shortage of Fe. Cellular composition was also influenced by Fe deficiency, showing lower chl a content in the Fe-stressed cells. Chl a per cell volume decreased by 30% as temperature decreased from 20 to 10 C under Fe-replete conditions, but chl a decreased by 50% from Fe-replete to Fe-stressed conditions.

Kudoh, S., B. Robineau, et al. (1997). "Photosynthetic acclimation and the estimation of temperate ice algal primary production in Saroma-ko Lagoon, Japan." Journal of Marine Systems 11(1-2): 93-109.
Temporal changes in the sea ice environment, ice algal biomass and photosynthetic characteristics were studied at Saroma-ko Lagoon in Japan, the area where the southernmost seasonal sea ice in the northern hemisphere occurs. In 1992, the sea ice started to develop in early January and covered the entire lagoon surface in late January, when water temperatures at the center of the lagoon decreased below -1.7 degrees C. High concentrations of ice algae in the bottom layer of the sea ice, where light levels were 0.5-2.8% of the surface irradiance, were visually confirmed in mid-February. The biomass increased in late February to a maximum of 38.25 mg Chl a m(-2) then suddenly decreased during stormy weather in early March. Afterwards it remained rather constant, with high values of 20- 30 mg Chl a m(-2) until mid-March. Photosynthesis vs. light analysis revealed that ice algae in this lagoon had a low dark respiration rate of 0.024 mg C mg Chl a(-1) h(-1) average while the increase of photosynthesis at light levels lower than 25 mu mol m(-2) s(-1) showed gentle linear increases with increments of light intensity. However, the maximum photosynthetic rate and the efficiency of the photosynthesis at low light levels were rather low compared with values from previous studies in the polar sea ice areas. Nevertheless, in situ estimates of net diel photosynthesis and production, which were calculated with a numerical model using the photosynthetic parameters and hourly averaged light at the ice algal habitat, suggested that large positive values were expected throughout this study. In temperate sea ice areas like Saroma-ko, where there are day/night light cycles, ice algae that have a small net loss of carbon at night due to dark respiration could achieve positive photosynthesis and growth even though they do not show the efficient photosynthesis under low light as shown by polar ice algae.

Kuhl, M., C. Lassen, et al. (1997). "A simple light meter for measurements of PAR (400 to 700 nm) with fiber-optic microprobes: application for P vs E-0(PAR) measurements in a microbial mat." Aquatic Microbial Ecology 13(2): 197-207.
A simple portable light meter for use with fiber-optic microprobes was developed. The meter has a flat spectral quantum responsivity for 400 to 700 nn light (photosynthetically available radiation, PAR). With scalar irradiance microprobes connected to the meter, it was possible to directly measure photosynthetically available quantum scalar irradiance, E-0(PAR), at <100 mu m spatial resolution and over a dynamic range from <1 to >1300 mu mol photons m(-2) s(-1). We used the new instrument for scalar irradiance measurements in microbial mats from a freshwater lake (Lake Stigsholm, Denmark) and from a hypersaline pond (Eilat, Israel). Combined measurements of quantum scalar irradiance by fiber-optic microprobes and oxygenic photosynthesis by oxygen microelectrodes made it possible to measure gross photosynthesis as a function of the prevailing scalar irradiance (Pvs Eo curves) at distinct depths within an undisturbed hypersaline microbial mat of immotile unicellular cyanobacteria (Aphanothece spp.). Intense photosynthesis by the cyanobacteria resulted in oxygen supersaturation and a 10-fold increase of oxygen penetration in the illuminated mat (z(max) = 2.5 mm) as compared to the oxygen penetration in dark incubated mats (z(max) = 0.2 to 0.3 mm). The mat changed from a net oxygen consuming to a net oxygen producing community at an oxygen compensation irradiance of 14 to 26 mu mol photons m(-2) s(-1). The photic zone of the microbial mat was only 0.6 mm deep due to a high attenuation of PAR. The diffuse vertical attenuation coefficient of E-0(PAR) was K-0(PAR) = 6.3 mm(-1). In the upper 0.2 mm of the microbial mat photosynthesis was photoinhibited at scalar irradiance above 200 mu mol photons m(-2) s(-1). At 0.3 mm the strong light attenuation prevented inhibition in deeper layers of the microbial mat and photosynthesis approached saturation at 35 mu mol photons m(-2) s(-1). In the lower part of the photic zone, photosynthesis increased linearly with E-0(PAR). Areal gross photosynthesis exhibited no photoinhibition at high irradiance and started to approach saturation above a downwelling quantum irradiane of 97 mu mol photons m(-2) s(-1).

Kuring, N. (2000). Faux Shuttle Views from SeaWiFS Data. Personal staff website: SeaWiFS image cookbook, SeaWiFS Goddard Space Flight Center. 2000.

Kyewalyanga, M. N., T. Platt, et al. (1997). "Estimation of the photosynthetic action spectrum: Implication for primary production models." Marine Ecology-Progress Series 146(1-3): 207-223.
A simple method for estimating the photosynthetic action spectrum is developed. The method uses the shape of the absorption spectrum of phytoplankton pigments, scaled to the magnitude of the initial slope of the photosynthesis-light curve as established for broad-band illumination. The method was tested by comparing the estimated action spectra with those measured during a cruise in the North Atlantic, in the fall of 1992. The agreement between the constructed and the measured spectra was good. Both the measured and constructed action spectra were then used to compute daily water-column primary production (P-Z,P-T) using a spectrally resolved model. The results showed that, at most of the stations, the P-Z,P-T computed using the constructed action spectrum was not significantly different from P-Z,P-T calculated using the measured spectrum. Daily water-column primary production was also computed at each station using the average shape of the measured action spectra (spectra averaged over all stations), scaled to the magnitude of broad-band initial slope at that station. The results were similar to the P-Z,P-T values computed using the action spectra constructed for individual stations. The errors that may affect the constructed action spectrum are assessed through a sensitivity analysis. The analysis suggests that, for our data, the presence of photosynthetically inactive pigments causes negligible errors in the computed P-Z,P-T. An assessment of the effects of random errors in the action spectrum showed that the error in the computed primary production was on average 1.5% (under the conditions chosen for the computation), when random errors of up to +/-20% were introduced into the action spectrum. However, given similar conditions, systematic errors of similar magnitude in the action spectrum cause an average error of about 6% in the computed water-column primary production.

Lande, R. and M. R. Lewis (1989). "Models of photoadaptation (find the rest)."

Lande, R. and M. R. Lewis (1989). "Models of Photoadaptation and Photosynthesis by Algal Cells in a Turbulent Mixed Layer." Deep-Sea Research Part a-Oceanographic Research Papers 36(8): 1161-1175.

Lande, R., W. K. W. Li, et al. (1989). "Rapid Response Paper: Phytoplankton growth rates estimated from depth profiles of cell concentration and turbulent diffusion." Deep-Sea Research 36(8): 1141-1159.

Langdon, C. (1987). "On the causes of interspecific differences in the growth-irradiance relationship for phytoplankton. Part I. A comparative study of the growth-irradiance relationship of three marine phytoplankton species: Skeletonema costatum, Olithodiscus leuteus and Gonyaulax tamarensis." J. Plankton Res. 9: 459-482.

Laws, E. a. and T. T. Bannister (1980). "Nutrient and light limited growth of Thalassiosira fluviatilis in continuous culture, with implications for phytoplankton growth in the ocean." Limnol. Oceanogr. 25: 457-73.

Laws, E. a., G. R. Di Tullio, et al. (1990). "Rapid Response Paper: Primary production in the deep blue sea." Deep-Sea Research 37(5): 715-730.

Lazzara, L., A. Bricaud, et al. (1996). "Spectral absorption and fluorescence excitation properties of phytoplanktonic populations at a mesotrophic and an oligotrophic site in the tropical North Atlantic (EUMELI program)." Deep-Sea Research Part I-Oceanographic Research Papers 43(8): 1215-1240.

Leboulanger, C., F. Rimet, et al. (2001). "Effects of atrazine and nicosulfuron on freshwater microalgae." Environment International 26(3): 131-135.
Growth modifications caused by various concentrations of atrazine and nicosulfuron were monitored in closed and continuous culture of Chlorella vulgaris (chlorophyta), Navicula accommoda (diatomophyta), and Oscillatoria limnetica (cyanophyta). The concentration at which algal growth rate was reduced twofold (EC50) was determined in the three species for both herbicides. Comparatively the two toxicants were applied at 10 mug/l level in microcosms inoculated with natural phytoplankton from Lake Geneva. The relative abundances of major phytoplanktonic species were measured by algal cell count at the beginning and at the end of each experiment. Atrazine and nicosulfuron have different targets in plant metabolism respectively, photosystem II (PSII) and acetolactate synthase (ALS), and the expected effects were different. Generally, the cultured phytoplankton exhibited various sensitivities, depending on species or herbicide. In the microcosms, the major taxa of natural phytoplanktonic samples exhibited various patterns, from acute toxicity to growth enhancement. For example, the diatoms inside the community were not affected by atrazine and nicosulfuron, except for Stephanodiscus minutulus that was sensitive to both, and Asterionella formosa that was sensitive only to nicosulfuron. The specific physiology and the relationships among the phytoplanktonic communities have to be carefully considered when one would try to predict the extent of herbicide action on natural phytoplankton using in vitro tests. There is a need to test the toxic effect on various cultured strains, representative of most of the taxonomic composition of natural communities, to take into account the wide range of sensitivities and reaction to herbicide contamination. But this is not enough to give a solid frame when transposing the results to the field, and the use of more ecologically relevant systems is recommended. (C) 2001 Elsevier Science Ltd. All rights reserved.

Legendre, L., S. Demers, et al. (1988). "Circadian Photosynthetic Activity of Natural Marine- Phytoplankton Isolated in a Tank." Journal of Plankton Research 10(1): 1-6.

Legendre, L., F. Rassoulzadegan, et al. (1999). "Identifying the dominant processes (physical versus biological) in pelagic marine ecosystems from held estimates of chlorophyll a and phytoplankton production." Journal of Plankton Research 21(9): 1643-1658.
A new approach is described to identify the dominant process (physical versus biological) in a pelagic marine ecosystem, from simple biological oceanographic field variables. The approach is based on quantification of the matching (M) between phytoplankton production (P) and losses, from held estimates of chlorophyll a (Chl) and P. Coefficient Ail is estimated for a wide range of oceanic and coastal environments and of trophic characteristics, using data from the literature. Results show that M characterizes the dominance of physical versus biological processes in pelagic systems. The coefficient may be especially useful as a means for extracting process information on pelagic marine ecosystems from large data sets of Chi and P, e.g. recorded by moored instruments or provided by satellite images of ocean colour.

Leitao, M. and L. Leglize (2000). "Long-term variations of epilimnetic phytoplankton in an artificial reservoir during a 10-year survey." Hydrobiologia 424: 39-49.
Vieux-Pre' is an artificial reservoir in the north-east part of France (61 Mm(3)), created in 1986 for hydraulic management. The phytoplankton and several environmental parameters in the upper part of the lake were monitored at a mid-lake station, from 1988 to 1997. The specific composition of the community changed during this period, from a predominantly pennate-diatom phytoplankton (Asterionella formosa, Fragilaria crotonensis), the lake passed to dominance by a sparse, motile nanoplankton (Mallomonas akrokomos, M. caudata, Cryptomonas erosa, Chroomonas/Rhodomonas, a.o.) and then by large colonies of small-celled species (Uroglena americana, Dinobryon spp., Radiocystis geminata, Aphanothece clathrata, Coelosphaerium kuetzingianum a.o.). This paper describes the algal successions involved and shows the decisive effects of the decrease of trophic level from an eutrophic stage to an oligo-mesotrophic condition. In the beginning, externally imposed disturbances (flooding and dewatering) were frequent, while now the lake has stabilised as a deep, stratified pelagic system. Under these conditions, autogenic phytoplankton appear to dominate.

Leshkevich, G. A., D. J. Schwab, et al. (1993). "Satellite Environmental Monitoring of the Great-Lakes - a Review of Noaas Great-Lakes Coastwatch Program." Photogrammetric Engineering and Remote Sensing 59(3): 371-379.
To address critical coastal environmental problems, the National Oceanic and Atmospheric Administration (NOAA) has established the Coastal Ocean Program. Within that program, CoastWatch is designed to provide a rapid supply of up-to-date, coordinated, environmental information, including remotely sensed data, to support Federal and state decision makers and researchers who are responsible for managing the Nation's living marine resources and ecosystems. This paper describes the NOAA CoastWatch program for the Great Lakes. The initial products of the CoastWatch program, a set of surface water temperature images, are routinely derived from NOAA AVHRR (Advanced Very High Resolution Radiometer) satellite data and made available within hours of acquisition. Preliminary analysis has shown excellent correlation of satellite-derived temperatures with in situ water temperature measurements from mid-lake weather buoys. Other products including turbidity, ocean color, and ice mapping are planned. Components of the Coast Watch system including a wide area communications system, on-line product data bases, an electronically-accessible product archive, and PC software for display and analysis of the satellite imagery are also described.

Lesser, M. P. (1996). "Acclimation of phytoplankton to UV-B radiation: Oxidative stress and photoinhibition of photosynthesis are not prevented by UV-absorbing compounds in the dinoflagellate Prorocentrum micans." Marine Ecology-Progress Series 132(1-3): 287-297.
Experiments on the temperate marine dinoflagellate Prorocentrum micans showed that cultures acclimated to moderate intensities (120 mu mol quanta m(-2) s(-1)) of visible radiation and supplemental ultraviolet (UV) radiation exhibited significant inhibition of photosynthesis. This inhibition of photosynthesis caused a significant 30 % decrease in specific growth rates for those cells exposed to UV radiation by the end of the 21 d culture. The mechanism for this decrease in chlorophyll specific photosynthetic rate does not appear to have been damage to photosystem II, as suggested for many acute exposure experiments. Rather, significant decreases in chlorophyll per cell and the specific activities of the carboxylating enzyme, Rubisco, explain the observed decrease in photosynthesis. The decrease in cellular chlorophyll and Rubisco activities occurs despite the presence and accumulation of mycosporine-like amino acids, whose UV absorbing properties have been suggested as an important protective mechanism against the deleterious effects of UV radiation. Our results also implicate oxidative stress, most likely a result of photodynamic interactions, as the cause for the decrease in Rubisco activities. Action spectra generated from these experiments show a significant decrease in the wavelength-dependent effects of UV radiation in cultures exposed to UV radiation, suggesting that UV-absorbing compounds do provide some, if not complete, protection. Previous predictions about specific changes in the shape of action spectra were centered around the absorption maximum of individual UV-absorbing compounds. The observed changes in the overall shape of the UV action spectra for photosynthesis in P. micans can be attributed to the broad overlapping absorption spectra of the suite of UV-absorbing compounds.

Lewis, M. R., J. J. Cullen, et al. (1984). "Relationships between vertical mixing and photoadaptation of phytoplankton: similarity criteria." Mar. Ecol. Prog. Ser. 15: 141-149.

Lewis, M. R., E. P. W. Horne, et al. (1984). "Turbulent motions may control phytoplankton photosynthesis in the upper ocean." Nature 311(5981): 49-50.

Lewis, M. R. and J. C. Smith (1983). "A small volume, short incubation time method for the measurement of photosynthesis as a function of incident irradiance." Mar. Ecol. Prog. Ser. 13: 99-102.

Lewis, M. R., O. Ulloa, et al. (1988). "Photosynthetic Action, Absorption, and Quantum Yield Spectra for a Natural-Population of Oscillatoria in the North-Atlantic." Limnology and Oceanography 33(1): 92-98.

Li, W. K. W., H. E. Glover, et al. (1980). "Physiology of carbon photoassimilation by Oscillatoria thiebautii in the Caribbean Sea." Limnol. Oceanogr. 25(3): 447-456.

Lignell, R. and K. Lindqvist (1992). "Effect of nutrient enrichment and temperature on intracellular partitioning of (14)CO2 in a summer phytoplankton community in the northern Baltic." Marine ecology progress series 86(3): 273.

Lizon, F., L. Seuront, et al. (1998). "Photoadaptation and primary production study in tidally mixed coastal waters using a Lagrangian model." Marine Ecology-Progress Series 169: 43-54.

Llewellyn, C. A. and R. F. C. Mantoura (1997). "A UV absorbing compound in HPLC pigment chromatograms obtained from Icelandic Basin phytoplankton." Marine Ecology-Progress Series 158: 283-287.
A UV absorbing compound was observed in surface waters of the Iceland Basin during the decline of a phytoplankton bloom in June 1989. The compound elutes early during reverse-phase HPLC analyses of phytoplankton chlorophylls and carotenoids and has a broad absorption band from 300 to 470 nm with an absorption maximum at 380 nm. The compound (subsequently referred to as P380) is characterised by similar, but not identical, elution properties and absorption spectrum to scytonemin, an ultraviolet sunscreen pigment not previously found in the phytoplankton. The similarity of P380 to mycosporine-like amino acids (MAAs) is also discussed. P380 concentrations are highest in surface waters, decline sharply within the upper euphotic zone, and are linearly correlated (r(2) = 0.68) with the photoprotective carotenoid diadinoxanthin.

Lohr, M. and C. Wilhelm (1999). "Algae displaying the diadinoxanthin cycle also possess the violaxanthin cycle." Proc. Natl. Acad. Sci. USA. 96: 8784-8789.

Lohrenz, S. E., D. A. Wiesenburg, et al. (1992). "A Comparison of Insitu and Simulated Insitu Methods for Estimating Oceanic Primary Production." Journal of Plankton Research 14(2): 201-221.
Primary production data measured by in situ (IS) and 'simulated' in situ (SIS) incubations were compared. To minimize differences between the two types of incubations, SIS experiments were conducted in temperature-controlled incubators in which the spectral distribution and irradiance were adjusted to approximate IS conditions. IS available irradiance (I(IS)) was computed from vertical attenuation of integrated surface irradiance. Vertical attenuation was estimated using a spectral irradiance model, validated by measured profiles of the vertical attenuation coefficient. IS incubations were carried out using two methods. The first involved deployment of bottles on a drifting array for whole-day (dawn to dusk) incubations. The second method employed an autonomous submersible incubation device that performed short term (< 1 h) incubations at multiple depths. Differences between whole-day IS and SIS incubation estimates were attributed partially to differences between I(IS) and SIS-available irradiance (I(SIS)). Photosynthesis-irradiance (P-I) properties of IS and SIS populations from the whole-day incubations were not significantly different. P-I properties of the short-term IS and SIS populations were significantly different, although estimates of P(B) (mg C mg Chl-1 h-1) from contemporaneous IS and SIS incubations did not differ by > 40%. Integrated water- column primary production (IPP) estimated using P-I models derived from SIS data were within 15% of IS estimates of IPP.

Lomas, M. W. and P. M. Glibert (2000). "Comparisons of nitrate uptake, storage, and reduction in marine diatoms and flagellates." J. Phycol. 36(5): 903-a-913.
Diatoms, but not flagellates, have been shown to increase rates of nitrogen release after a shift from a low growth irradiance to a much higher experimental irradiance. We compared NO3- uptake kinetics, internal inorganic nitrogen storage, and the temperature dependence of the NO3- reduction enzymes, nitrate (NR) and nitrite reductase (NiR), in nitrogen-replete cultures of 3 diatoms (Chaetoceros sp., Skeletonema costatum, Thalassiosira weissflogii) and 3 flagellates (Dunaliella tertiolecta, Pavlova lutheri, Prorocentrum minimum) to provide insight into the differences in nitrogen release patterns observed between these species. At NO3- concentrations <40 mol-NL-1, all the diatom species and the dinoflagellate P. minimum exhibited saturating kinetics, whereas the other flagellates, D. tertiolecta and P. lutheri, did not saturate, leading to very high estimated K s values. Above[~] 60 mol-NL-1, NO3- uptake rates of all species tested continued to increase in a linear fashion. Rates of NO3- uptake at 40 mol-NL-1, normalized to cellular nitrogen, carbon, cell number, and surface area, were generally greater for diatoms than flagellates. Diatoms stored significant amounts of NO3- internally, whereas the flagellate species stored significant amounts of NH4+. Half-saturation concentrations for NR and NiR were similar between all species, but diatoms had significantly lower temperature optima for NR and NiR than did the flagellates tested in most cases. Relative to calculated biosynthetic demands, diatoms were found to have greater NO3- uptake and NO3- reduction rates than flagellates. This enhanced capacity for NO3- uptake and reduction along with the lower optimum temperature for enzyme activity could explain differences in nitrogen release patterns between diatoms and flagellates after an increase in irradiance.

Lorenzen, C. J. (1967). "Determination of chlorophyll and pheo-pigments: spectrophotometric equations." Limnol. Oceanogr. 12: 343-346.

Lou, J., D. J. Schwab, et al. (2000). "A model of sediment resuspension and transport dynamics in southern Lake Michigan." Journal of Geophysical Research-Oceans 105(C3): 6591-6610.
A quasi-three-dimensional suspended sediment transport model was developed and generalized to include combined wave-current effects to study bottom sediment resuspension and transport in southern Lake Michigan. The results from a three-dimensional circulation model and a wind wave model were used as input to the sediment transport model. Two effects of nonlinear wave- current interactions were considered in the sediment transport model: the changes in turbulence intensity due to waves and the enhancement of induced bottom shear stresses. Empirical formulations of sediment entrainment and resuspension processes were established and parameterized by laboratory data and field studies in the lake. In this preliminary application of the model to Lake Michigan, only a single grain size is used to characterize the sedimentary material, and the bottom of the lake is treated as an unlimited sediment source. The model results were compared with measured suspended sediment concentrations at two stations and several municipal water intake turbidity measurements in southern Lake Michigan during November-December 1994. The model was able to reproduce the general patterns of high-turbidity events in the lake. A model simulation for the entire 1994-1995 two-year period gave a reasonable description of sediment erosion/deposition in the lake, and the modeled settling mass fluxes were consistent with sediment trap data. The mechanisms of sediment resuspension and transport in southern Lake Michigan are discussed. To improve the model, sediment classifications, spatial bottom sediment distribution, sediment source function, and tributary sediment discharge should be considered.

Maberly, S. C., M. A. Hurley, et al. (1994). "The Rise and Fall of Asterionella-Formosa in the South Basin of Windermere - Analysis of a 45-Year Series of Data." Freshwater Biology 31(1): 19-34.
1. The changes in abundance of Asterionella formosa in the South Basin of Windermere between 1946 and 1990 are described and analysed. The average seasonal cycle for the 45-year period shows an overwintering population of about 10 cell ml(-1) which increases with an exponential rate of 0.09 log(e) day(-1) to an annual maximum of 4000 cell ml(-1) by about Day 124. There is then a rapid decline at an exponential rate of loss of 0.29 log(e) day(-1) to values which typically are less than 0.01 cell ml(-1) in mid-summer. By about Day 240 a second period of rapid increase occurs with an exponential rate of increase of 0.18 log(e) day(-1) to a plateau of about 7 cell ml(-1) in late autumn and early winter. 2. This average pattern is subject to considerable year-to-year variation. The timing and extent of the increase in the autumn was particularly variable. The rate of increase in the spring was strongly positively correlated, and that in the autumn strongly negatively correlated, with the day at which the exponential phase started. Rates for these two phases of increase were not statistically different when expressed in terms of time from mid-summer, which reinforces earlier conclusions that light availability is the main factor governing the rate of spring increase and suggests that this is also the case for the autumn increase. 3. Eight descriptors of seasonal development showed statistically significant changes over the 45 years. Early winter populations declined from 27 to 4 cell ml(-1), and linked to this the day at which cell concentrations exceeded 50 cell ml(-1) occurred later by 24 days from Day 54 in 1946 to 78 in 1990. The lower early winter population appears to be linked to a lower end of year population as this decreased between 1946 and 1968 from 46 to 2 cell ml(-1), and then increased slightly to 7 cell ml(-1) in 1990. The start of the spring exponential increase occurred on Day 57 in 1946 and started earlier by 19 days in 1968 but then occurred later, at Day 76, in 1990. The duration of the spring increase got shorter by 23 days, from 67 days in 1946 to 44 days in 1990. The maximum rate of increase rose from 0.065 log(e) day(-1) in 1946 to 0.112 log(e) day(-1) in 1990. The annual maximum declined from 9863 cell ml(-1) in 1946 to 2278 cell ml(-1) in 1968 and then increased to 6159 cell ml(-1) in 1990. The annual geometric mean decreased from 61 cell ml(-1) in 1946 to 5 cell ml(-1) in 1968 and remained nearly constant subsequently. 4. In many cases, the precise underlying causes of these changes were not apparent. However, the increase with time of rate of increase in the spring appeared to be linked to a later start and hence growth under higher light. There was no significant cyclical change in any of the descriptors studied.

Maberly, S. C., M. A. Hurley, et al. (1994). "The Rise and Fall of Asterionella-Formosa in the South Basin of Windermere - Analysis of a 45-Year Series of Data." Freshwater Biology 31(1): 19-34.
1. The changes in abundance of Asterionella formosa in the South Basin of Windermere between 1946 and 1990 are described and analysed. The average seasonal cycle for the 45-year period shows an overwintering population of about 10 cell ml(-1) which increases with an exponential rate of 0.09 log(e) day(-1) to an annual maximum of 4000 cell ml(-1) by about Day 124. There is then a rapid decline at an exponential rate of loss of 0.29 log(e) day(-1) to values which typically are less than 0.01 cell ml(-1) in mid-summer. By about Day 240 a second period of rapid increase occurs with an exponential rate of increase of 0.18 log(e) day(-1) to a plateau of about 7 cell ml(-1) in late autumn and early winter. 2. This average pattern is subject to considerable year-to-year variation. The timing and extent of the increase in the autumn was particularly variable. The rate of increase in the spring was strongly positively correlated, and that in the autumn strongly negatively correlated, with the day at which the exponential phase started. Rates for these two phases of increase were not statistically different when expressed in terms of time from mid-summer, which reinforces earlier conclusions that light availability is the main factor governing the rate of spring increase and suggests that this is also the case for the autumn increase. 3. Eight descriptors of seasonal development showed statistically significant changes over the 45 years. Early winter populations declined from 27 to 4 cell ml(-1), and linked to this the day at which cell concentrations exceeded 50 cell ml(-1) occurred later by 24 days from Day 54 in 1946 to 78 in 1990. The lower early winter population appears to be linked to a lower end of year population as this decreased between 1946 and 1968 from 46 to 2 cell ml(-1), and then increased slightly to 7 cell ml(-1) in 1990. The start of the spring exponential increase occurred on Day 57 in 1946 and started earlier by 19 days in 1968 but then occurred later, at Day 76, in 1990. The duration of the spring increase got shorter by 23 days, from 67 days in 1946 to 44 days in 1990. The maximum rate of increase rose from 0.065 log(e) day(-1) in 1946 to 0.112 log(e) day(-1) in 1990. The annual maximum declined from 9863 cell ml(-1) in 1946 to 2278 cell ml(-1) in 1968 and then increased to 6159 cell ml(-1) in 1990. The annual geometric mean decreased from 61 cell ml(-1) in 1946 to 5 cell ml(-1) in 1968 and remained nearly constant subsequently. 4. In many cases, the precise underlying causes of these changes were not apparent. However, the increase with time of rate of increase in the spring appeared to be linked to a later start and hence growth under higher light. There was no significant cyclical change in any of the descriptors studied.

Macedo, M. F., J. G. Ferreira, et al. (1998). "Dynamic behaviour of photosynthesis-irradiance curves determined from oxygen production during variable incubation periods." Marine Ecology-Progress Series 165: 31-43.

MacIntyre, H. L., T. M. Kana, et al. (2000). "The effect of water motion on short-term rates of photosynthesis by marine phytoplankton." Trends in Plant Science 5(1): 12-17.

Mackey, D. J., H. W. Higgins, et al. (1998). "Algal class abundances in the western equatorial Pacific: Estimation from HPLC measurements of chloroplast pigments using CHEMTAX." Deep-Sea Research Part I-Oceanographic Research Papers 45(9): 1441-1468.
Samples for the analysis of phytoplankton photosynthetic pigments were collected from the equatorial Pacific (5 degrees N to 15 degrees S along 155 degrees E) in October 1990 as part of the Australian contribution to the JGOFS program. Chlorophyll and carotenoid pigments were measured by HPLC using a diode-array detector. A PC-based computer program was used to optimise the pigment ratios and to estimate the contributions of 10 algal classes to the total chlorophyll a concentration at each location and in 7 separate depth bands. For the pigments that occur in more than one algal class, the pigment: chlorophyll a ratios for 19'-butanoyloxyfucoxanthin and 19'- hexanoyloxyfucoxanthin (chrysophytes and haptophytes), neoxanthin (prasinophytes, euglenophytes and chlorophytes) and chlorophyll b (prasinophytes, euglenophytes, prochlorophytes and chlorophytes) increase with depth, while those of violaxanthin (prasinophytes and chlorophytes), diadinoxanthin (dinoflagellates, chrysophytes, haptophytes, euglenophytes and diatoms), lutein (prasinophytes and chlorophytes) and, zeaxanthin (prasinophytes, cyanobacteria, prochlorophytes and chlorophytes) decrease with depth. Peridinin: chlorophyll a increases with depth in dinoflagellates, while alloxanthin: chlorophyll a decreases with depth in cryptomonads. The only pigment ratio that does not change consistently with depth is that of fucoxanthin, which increases with depth in chrysophytes and haptophytes but decreases in diatoms. Based on their contribution to the total chlorophyll a, cyanobacteria (Synechococcus) were dominant in the nutrient depleted surface waters, haptophytes were dominant at mid depth (70 m), and prochlorophytes were dominant at depths of 100-125 m. These three algal classes were by far the most important, and each contributed up to 30-40% of the total chlorophyll a at some depth within the water column. Chlorophytes and chrysophytes contributed up to a maximum of about 12% of the total chlorophyll a, while cryptophytes, diatoms, dinoflagellates, prasinophytes and (possibly) euglenophytes generally contributed up to 4-8% of the chlorophyll a. (C) 1998 Elsevier Science Ltd. All rights reserved.

Mackey, M. D., D. J. Mackey, et al. (1996). "CHEMTAX - A program for estimating class abundances from chemical markers: Application to HPLC measurements of phytoplankton." Marine Ecology-Progress Series 144(1-3): 265-283.
We describe a new program for calculating algal class abundances from measurements of chlorophyll and carotenoid pigments determined by high-performance liquid chromatography (HPLC). The program uses factor analysis and a steepest descent algorithm to find the best fit to the data based on an initial guess of the pigment ratios for the classes to be determined. The program was tested with a range of synthetic data-sets that were constructed from known pigment ratios selected to be representative of samples of phytoplankton collected from the Southern Ocean and the Equatorial Pacific. Random errors were added both to the pigment ratios and to the calculated data- sets to simulate both uncertainties in the initial guess as to the pigment concentrations of each class and respectively experimental errors in the analysis of the pigments by HPLC. Provided that the analytical data is of good quality, the program can successfully determine the class abundances, even when the initial estimates of the pigment ratios contain large errors. Of particular interest is the observation that the program can provide good estimates of prochlorophytes, even in the absence of experimental data on the concentrations of divinyl-chlorophylls a and b. The program is not restricted to the estimation of phytoplankton and can be used whenever specific biomarkers exist that can be used as indicators of biological or chemical processes.

Mantoura, R. F. C. and C. A. Llewellyn (1983). "The rapid determination of algal chlorophyll and carotenoid pigments and their breakdown products in natural waters by reverse-phase high performance liquid chromatography." Anal. Chim. Acta. 151: 297-314.

Maranon, E. and P. M. Holligan (1999). "Photosynthetic parameters of phytoplankton from 50 degrees N to 50 degrees S in the Atlantic Ocean." Marine Ecology-Progress Series 176: 191-203.
We conducted 150 photosynthesis-irradiance (P-E) experiments along 2 Atlantic meridional transects from 50 degrees N to 50 degrees S in April-May and October-November 1996. The latitudinal and vertical distributions of the maximum chlorophyll a-normalized rate of photosynthesis (P-m(B)) and the initial slope of the P-E curve (alpha(B)) were examined in relation to the Variations in relevant physical, chemical and biological variables. P-m(B) ranged from <1 mg C mg chl(-1) h(- 1) in the central oligotrophic gyres to >10 mg C mg chl(-1) h(- 1) in temperate regions and the upwelling area off Mauritania. The dynamic range of the observed variations in the P-E parameters was 3 to 4 times higher than assumed in productivity models that divide the ocean into biogeochemical provinces. Variability in the physiological parameters of phytoplankton was as high as that of chlorophyll concentration. We obtained a model of multiple linear regression to calculate integrated primary productivity from data of surface temperature, chlorophyll a and P-m(B). Changes in P-m(B) accounted for 30% of the total variability in productivity, whereas variations in chlorophyll a explained only 5%, which indicates that phytoplankton photophysiology is more relevant than biomass in the control of primary productivity. We found a significant, negative correlation between the latitudinal changes in P-m(B), and those in the depth of the nitracline, suggesting an important role for the nutrient supply from below the thermocline in the regulation of photosynthetic efficiency over large spatial scales. A large degree of temporal variability was observed in the subtropical gyres: P-m(B) and alpha(B) varied by a factor of 3 between the 2 cruises, whereas phytoplankton biomass remained constant. The differences in the photosynthetic parameters between seasons were larger than between biogeochemical provinces. We emphasize the need to include nutrient-driven changes of phytoplankton photophysiology in models of primary productivity.

Maritorena, S. and J. E. O' Reilly (2000). OC2v2: Update on the initial operational SeaWiFS chlorophyll a algorithm. Volume 11,SeaWiFS Postlaunch Calibration and
Validation Analyses,Part 3, NASA Goddard Space Flight Center.

Markager, S., W. F. Vincent, et al. (1999). "Carbon fixation by phytoplankton in high Arctic lakes: Implications of low temperature for photosynthesis." Limnology and oceanography 44(3): 597.

Marra, J. (1978). "Phytoplankton photosynthetic response to vertical movement in a mixed layer." Mar. Biol. 46: 203-208.

Marra, J. (1980). Vertical mixing and primary production. In: Primary productivity in the sea, P. G. Falkowski. New York, Plenum Press: 531.

Martin-Jezequel, V., M. Hildebrand, et al. (2000). "Silicon metabolism in diatoms: implications for growth." J. Phycol. 36(5): 821-840.
Diatoms are the world's largest contributors to biosilicification and are one of the predominant contributors to global carbon fixation. Silicon is a major limiting nutrient for diatom growth and hence is a controlling factor in primary productivity. Because our understanding of the cellular metabolism of silicon is limited, we are not fully knowledgeable about intracellular factors that may affect diatom productivity in the oceans. The goal of this review is to present an overview of silicon metabolism in diatoms and to identify areas for future research. Numerous studies have characterized parameters of silicic acid uptake by diatoms, and molecular characterization of transport has begun with the isolation of genes encoding the transporter proteins. Multiple types of silicic acid transporter gene have been identified in a single diatom species, and multiple types appear to be present in all diatom species. The controlled expression and perhaps localization of the transporters in the cell may be factors in the overall regulation of silicic acid uptake. Transport can also be regulated by the rate of silica incorporation into the cell wall, suggesting that an intracellular sensing and control mechanism couples transport with incorporation. Sizable intracellular pools of soluble silicon have been identified in diatoms, at levels well above saturation for silica solubility, yet the mechanism for maintenance of supersaturated levels has not been determined. The mechanism of intracellular transport of silicon is also unknown, but this must be an important part of the silicification process because of the close coupling between silica incorporation and uptake. Although detailed ultrastructural analyses of silica deposition have been reported, we know little about the molecular details of this process. However, proteins occluded within silica that promote silicification in vitro have recently been characterized, and the application of molecular techniques holds the promise of great advances in this area. Cellular energy for silicification and transport comes from aerobic respiration without any direct involvement of photosynthetic energy. As such, diatom silicon metabolism differs from that of other major limiting nutrients such as nitrogen and phosphorous, which are closely linked to photosynthetic metabolism. Cell wall silicification and silicic acid transport are tightly coupled to the cell cycle, which results in a dependency in the extent of silicification on growth rate. Silica dissolution is an important part of diatom cellular silicon metabolism, because dissolution must be prevented in the living cell, and because much of the raw material for mineralization in natural assemblages is supplied by dissolution of dead cells. Perhaps part of the reason for the ecological success of diatoms is due to their use of a silicified cell wall, which has been calculated to impart a substantial energy savings to organisms that have them. However, the growth of diatoms and other siliceous organisms has depleted the oceans of silicon, such that silicon availability is now a major factor in the control of primary productivity. Much new progress in understanding silicon metabolism in diatoms is expected because of the application of molecular approaches and sophisticated analytical techniques. Such insight is likely to lead to a greater understanding of the role of silicon in controlling diatom growth, and hence primary productivity, and of the mechanisms involved in the formation of the intricate silicified structures of the diatom cell wall.

Masojidek, J., J. U. Grobbelaar, et al. (2001). "Photosystem II electron transport rates and oxygen production in natural waterblooms of freshwater cyanobacteria during a diel cycle." Journal of Plankton Research 23(1): 57-66.
The relationship between electron transport rate through PSII and photosynthetic oxygen evolution in cyanobacterial surface waterblooms was followed over a diel cycle. Chlorophyll fluorescence and photosynthetic oxygen evolution (PSOE) measurements were performed in a small-volume incubation chamber an samples taken from a fish pond, Measurement of light-response curves showed a close to linear relationship between electron transport rates (ETR) and PSOE up to irradiancies of 800 pmol quanta m(-2) s(-1), except during mid- morning conditions. At higher irradiances, the relationship was non-linear. The regression coefficient kappa (= PSOE/ETR) exhibited wide variation during the day (3.8-9.2), indicating that the use of ETR as a measure of PSOE in cyanobacterial waterblooms should be approached with caution. The involvement of alternate oxygen-consuming electron transfer pathways is discussed as a possible explanation for this discrepancy.

Merilainen, J. J., J. Hynynen, et al. (2000). "Importance of diffuse nutrient loading and lake level changes to the eutrophication of an originally oligotrophic boreal lake: a palaeolimnological diatom and chironomid analysis." Journal of Paleolimnology 24(3): 251-270.
The recent environmental history of Lake Lappajarvi in western Finland (63 degrees 00' N, 23 degrees 30' E, area 149 km(2)), a humic, brown water lake with an average phosphorus content of ca. 20 mug l(-1), was studied from short core sediment samples taken from the two main basins of the lake. Based on the stratigraphy of diatoms and chironomids and the sediment quality it was possible to distinguish four developmental stages during the past century: (1) a pre-industrial stage covering the time up to about 1935; (2) a stage of increasing nutrient loading (ca. 1936-1960); (3) a stage of pronounced erosion from lake level regulation and extensive ditching of the catchment area (ca. 1960-1970); and (4) a meso-eutrophic stage from ca. 1970 onwards. Acidophilous Aulacoseira distans coll. and other species typical of dystrophic, nutrient-poor lakes characterized the diatom assemblages during the first stage, and the profundal zoobenthic assemblages, characterized by Heterotrissocladius subpilosus and Micropsectra, indicated good hypolimnetic oxygen conditions and a low sedimentation of organic matter (approx. less than 50 g m(-)2 a(-)1). The increased loading rapidly led to changes both in diatoms and chironomids (e.g., to an early extinction of H. subpilosus in the 1950s). The process finally led to eutrophication with a successive proliferation of diatom species such as Asterionella formosa followed by Aulacoseira ambigua, Fragilaria crotonensis, and finally Melosira varians. The relative proportion of alkaliphilous species reached a maximum in the final stage and the original profundal chironomid fauna was replaced by Chironomus anthracinus gr. and C. plumosus which are typical of profundal areas suffering from temporal oxygen deficit. It is notable that the considerable decrease in waste water loading from the point sources (80-86% ) during the past two decades has not led to a recovery in the lake. This highlights the importance of diffuse loading from agriculture, forestry and other human activities even to this comparatively large lake.

Meyer, S. L. (?). Data Analysis for Scientists and Engineers.

Meyercordt, J., S. Gerbersdorf, et al. (1999). "Significance of pelagic and benthic primary production in two shallow coastal lagoons of different degrees of eutrophication in the southern Baltic Sea." Aquatic Microbial Ecology 20(3): 273-284.

Mike Behrenfeld, G., NASA and I. or Dorota Kolber, Rutgers University (2000). IMCS Ocean Primary Productivity Team's (OPPT) home page, Rutgers, The State University of New Jersey Institute of Marine and Coastal Sciences. 2001.

Millie, D. F., M. O. Schofield, et al. (1997). "Detection of harmful algal blooms using phtopigments and absorption signatures: A case study of te Florida red tide dinoflagellate, Gymnodinium breve." Limnol. Oceanogr. 42(5, part2): 1240-1251.

Mingelbier, M., B. Klein, et al. (1994). "Measurement of Daily Primary Production Using 24-H Incubations with the C-14 Method - a Caveat." Marine Ecology-Progress Series 113(3): 301-309.
Computer simulations and experiments with cultured and natural phytoplankton were used to study C-14 uptake kinetics and budgets over 24 h incubations. There was good agreement between experiments and simulations. After 24 h incubations and depending on the starting time of incubations, net C-14 uptake varied by a factor of 2 in the laboratory and by a factor of 3 in the field. Both simulated and experimental data showed lowest C-14 accumulation for incubations starting at sunrise (i.e. dawn-to-dawn incubation), while highest values corresponded to incubations beginning at sunset. Recommendations for field studies are as follows. For samples collected at night, incubations can be started at any time, but should be conducted for a full 24 h after dawn. Samples collected after dawn should be incubated for 24 h, and C-14 accumulation should be corrected in order to obtain dawn-to- dawn values.

Moore, L. R. and S. W. Chisholm (1999). "Photophysiology of the marine cyanobacterium Prochlorococcus: Ecotypic differences among cultured isolates." Limnology and Oceanography 44(3): 628-638.

Morel, A. (1991). "Light and Marine Photosynthesis - a Spectral Model with Geochemical and Climatological Implications." Progress in Oceanography 26(3): 263-306.
Recent studies by MOREL (1978) and PLATT, SATHYENDRANATH, CAVERHILL and LEWIS (1988) have demonstrated the relative stability of the relationship between available photosynthetic energy at the ocean surface and energy stored by algal photosynthesis, once it has been normalized with respect to the column integrated chlorophyll biomass. Therefore the cross section vis a vis photosynthesis and per unit of areal chlorophyll, phi*, in m2 (g Chl)-1, should be relatively stable in spite of the various environmental and trophic situations possibly encountered in the open ocean. Such an ecological or biogeochemical "constant" is of importance when trying to transform biomass maps (obtained from remotely sensed ocean colour data) into primary production maps. Its approximate constancy has to be understood and deserves analysis. This analysis rests on the use of the local and instantaneous growth rate equation (KIEFER and MITCHELL, 1983) which has to be triply integrated with respect to wavelength, depth and time. Such an integration is, in effect, the core of a light production model which schematically includes the following steps: (i) to compute as a function of the sun elevation for various days, latitudes and atmospheric conditions (aerosols, water vapour, etc.) the photosynthetic energy impinging at the ocean surface (direct and diffuse components); (ii) to account for the loss by reflection at the air-sea interface; (iii) to propagate this radiant energy (in terms of spectral scalar irradiance) throughout the water column and according to given pigment vertical profiles; (iv) to evaluate what part of energy is absorbed by algae within the productive column; (v) and finally to compute that part of absorbed energy which is stored in the form of organic carbon added to the initial biomass; this last step implies that the yield for growth be modelled as a function of the irradiance level and temperature. Sensitivity tests have been effected with respect not only to the physical parameters which can be accurately modelled, but also with respect to the physiological factors for which values and parameterisation are more uncertain. Non-linear and interactive influences cause the phi* values obtained by running the model, to vary within a rather restricted range (within a factor 2, for most of the trophic and environmental conditions), which are similar to those resulting from field studies. The variability of the biomass-normalized primary production can be explained and the seasonal or zonal trends illustrated. The effect of cloudiness is also analyzed. This spectral light - photosynthesis model (a sub model in the more general study of the biomass evolution) can be used either to reproduce primary production experiments and also as a predictive tool in the oceanic carbon fixation problem. The global scale made accessible by satellite techniques requires that a climatological field of the phi* parameter be produced. This can be done by operating the present model, provided that the physiological factors which intervene are sufficiently ascertained and adequately parameterised, and also provided that the vertical distribution of the algal biomass can be inferred from the partial information (restricted to the upper layer) delivered by ocean colour sensors.

Morel, A. and B. Gentili (1991). "Diffuse reflectance of oceanic waters: Its dependence on Sun angle as influenced the moleculare scattering contribution." Appl. Opt. 30: 4427-4438.

Morel, A. and B. Gentili (1993). "Diffuse reflectance of oceanic waters, II: Bi-directional aspects." Appl. Opt. 32: 6864-6879.

Morel, A., L. Lazzara, et al. (1987). "Growth rate and quantum yield time response for a diatom to changing irradiances (energy and color)." Limnol. Oceanogr. 32(5): 1066-1084.

Morel, A. and L. Prieur (1977). "Analysis of variations in ocean color." Limnology and Oceanography 22: 709-722.

Morin, A., W. Lamoureux, et al. (1999). "Empirical models predicting primary productivity from chlorophyll a and water temperature for stream periphyton and lake and ocean phytoplankton." Journal of the North American Benthological Society 18(3): 299-307.
Published data on stream periphyton, lake phytoplankton, and ocean phytoplankton were analyzed to 1) quantify regression models relating daily gross primary production (GPP) to chlorophyll a (chl a) standing stock and water temperature, 2) compare regressions across assemblages, and 3) compare the precision of regression estimates of daily primary production and of production integrated over time to those obtained by measurements using radioisotopes. Regression models predicting daily GPP explained between 29% and 86% of the variance in Log GPP with chi a accounting for 28 to 85% of the explained variance. Regression models differed significantly across assemblages. Chlorophyll-specific production, corrected for the effect of temperature, declined with increasing chi a standing stock presumably because of increased self shading, and was lower in stream periphyton than in lake or marine phytoplankton presumably because of reduced nutrient diffusion in algal mats. Gross primary production was more intensely related to water temperature in stream periphyton (Q(10) = 2.5) than in either ocean phytoplankton (Q(10) = 1.2) or lake phytoplankton (Q(10) = 1.4). Precision measured as the error factor (EF) by which means have to be multiplied or divided to obtain the limits of a 95% confidence interval, was lower for regression estimates of daily production (EF = 3.4-6.7) and for production integrated over time (EF = 3.4) than for measurements of daily production (EF = 1.2-2). Considering the reduced effort required to obtain estimates of primary production using these regression models, we argue that they could be useful when coarse production estimates are sufficient or when adequate resources are not available to make direct measurements.

Mortimer, C. H. (1983). Special Report No. Not completed: Hydrodynamic Interactions with the Biosphere in Large Lakes. Milwaukee, WI, U.S Department of Commerce, National Oceanic and Atmospheric Administration: i-85.

Mouget, J. L., J. Delanoue, et al. (1995). "Long-Term Acclimatization of Scenedesmus-Bicellularis to High- Frequency Intermittent Lighting (100 Hz) .1. Growth, Photosynthesis and Photosystem-Ii Activity." Journal of Plankton Research 17(4): 859-874.
Responses of the green microalga, Scenedesmus bicellularis to high-frequency intermittent lighting (IL, 100 Hz) were assessed after a 4 week acclimatization. Effects of IL on growth, photosynthesis and photosystem II (PSII) activity were studied at limiting and saturating irradiances, and compared to those of continuous light (CL) of the same instantaneous and daily irradiances. Even after a 4 week acclimatization period, the photosynthetic capacity (P-max), the photosynthetic efficiency (alpha) and the photosynthetic activity at growth irradiance, either expressed on a per cell or a chlorophyll a basis, showed little difference, neither did the index of light adaptation (I-k) or PSII activity. In contrast, growth was lower under IL at saturating irradiance. Results are discussed considering the non-linearity of the relationship between growth or photosynthesis and irradiance.

Mouget, J. L., J. Delanoue, et al. (1995). "Long-Term Acclimatization of Scenedesmus-Bicellularis to High- Frequency Intermittent Lighting (100 Hz) .1. Growth, Photosynthesis and Photosystem-Ii Activity." Journal of Plankton Research 17(4): 859-874.
Responses of the green microalga, Scenedesmus bicellularis to high-frequency intermittent lighting (IL, 100 Hz) were assessed after a 4 week acclimatization. Effects of IL on growth, photosynthesis and photosystem II (PSII) activity were studied at limiting and saturating irradiances, and compared to those of continuous light (CL) of the same instantaneous and daily irradiances. Even after a 4 week acclimatization period, the photosynthetic capacity (P-max), the photosynthetic efficiency (alpha) and the photosynthetic activity at growth irradiance, either expressed on a per cell or a chlorophyll a basis, showed little difference, neither did the index of light adaptation (I-k) or PSII activity. In contrast, growth was lower under IL at saturating irradiance. Results are discussed considering the non-linearity of the relationship between growth or photosynthesis and irradiance.

Mouget, J. L., L. Legendre, et al. (1995). "Long-Term Acclimatization of Scenedesmus-Bicellularis to High- Frequency Intermittent Lighting (100 Hz) .2. Photosynthetic Pigments, Carboxylating Enzymes and Biochemical-Composition." Journal of Plankton Research 17(4): 875-890.
The long-term responses of the green microalga, Scenedesmus bicellularis, to a 100 Hz quasi-square wave (intermittent light, IL) were assessed after a 4 week acclimatization period. At the end of this period, the photosynthetic pigments, carboxylating enzyme activities and biochemical composition of algae grown under IL were compared to those of algae acclimatized to a light flux without fluctuations (continuous light, CL). Differences between IL and CL treatments were small. IL cells grown under limiting irradiance had characteristics close to CL cells grown at the same daily irradiance. At saturating irradiance, the characteristics of IL cells resembled those of CL cells at the same instantaneous irradiance, mostly because of the flattened response of microalgae to increased irradiance. The flickering of any artificial lighting system (100-120 Hz) can thus be neglected when such light is used to grow algae.

Mouget, J. L., G. Tremblin, et al. (1999). "Long-term photoacclimation of Haslea ostrearia (Bacillariophyta): effect of irradiance on growth rates, pigment content and photosynthesis." European Journal of Phycology 34(2): 109-115.

Munoz, M. D. R. and M. A. M. Arroyo (1999). "Photosynthesis-irradiance response of nanoplankton in two urban aquatic ecosystems." Revista De Biologia Tropical 47: 37-42.

Neale, P. J., J. J. Cullen, et al. (1998). "Inhibition of marine photosynthesis by ultraviolet radiation: Variable sensitivity of phytoplankton in the Weddell-Scotia Confluence during the austral spring." Limnology and Oceanography 43(3): 433-448.

Neale, P. J., S. I. Heaney, et al. (1991). "Responses to High Irradiance Contribute to the Decline of the Spring Diatom Maximum." Limnology and Oceanography 36(4): 761-768.
The effect of high irradiance was studied with cultures and samples from natural populations of the colonial diatom Asterionella formosa Hass. The fluorescence ratio F-nu:F(m), where F-nu is the difference between DCMU-enhanced fluorescence (F(m)) and normal, dark-adapted fluorescence (F0), was used as a relative measure of photosynthetic performance. A. formosa grown in batch culture displayed a 70-80% decrease in F-nu:F(m) during 1 h of exposure to 1,60-mu-mol quanta m-2 s-1. In addition, sinking rate increased from a mean of 0.23 m d-1 in controls to 0.43 after high irradiance. A. formosa populations were sampled in May, the later stage of the spring abundance maximum in the north basin of Windermere (English Lake District). Diatoms in the upper 1-3 m exhibited low F-nu:F(m) (0.1-0.2) during near-surface stratification (four of five dates) but no depression of F-nu:F(m) on the one occasion of sunny weather and strong surface winds. Near-surface cell abundances were also significantly lower during high- irradiance, stratified conditions. The results suggest that high irradiance lowers production rates and increases sedimentation of diatom populations during the later stages of the spring maximum.

Neale, P. J. and P. J. Richerson (1987). "Photoinhibition and the Diurnal-Variation of Phytoplankton Photosynthesis .1. Development of a Photosynthesis-Irradiance Model from Studies of Insitu Responses." Journal of Plankton Research 9(1): 167-193.

Neale, P. J., J. F. Talling, et al. (1991). "Long-Time Series from the English Lake District - Irradiance- Dependent Phytoplankton Dynamics During the Spring Maximum." Limnology and Oceanography 36(4): 751-760.
We analyzed rates of phytoplankton increase and decline during the spring maximum via long-term (25 yr) records of biomass (Chl a) and abundance of the dominant diatom, Asterionella formosa, sampled from the surface waters of Windermere (English Lake District). Average rates of net increase in early spring (i.e. up until the end of March) are best correlated with the logarithm of surface irradiance (r2 = 0.71-0.87). Average spring growth rates in late February and March (weeks 6-13 of the year) defined by this analysis significantly exceed rates predicted from calculations of integrated production with existing physiological data for A. formosa but are similar to the predicted growth rates at the mean irradiance in the mixed layer. In late spring (April-May), stratification becomes well established and the rate of population increase lessens. This decrease occurs before dissolved silicate is depleted to growth-limiting concentrations during increasing average irradiance in the surface layer. Near exhaustion of dissolved silicate and rapid loss of A. formosa from the surface layer follow. P limitation, enhanced sedimentation, and photoinhibition are factors that may slow net diatom accumulation before the onset of silicate limitation.

Necsoiu, M. and K. Turpie (2001). Homepage for NASA Goddard Space Flight Center Ocean Primary Productivity Science Computing Facility.

Neveux, J. D., J. C. Delmas, et al. (1990). "Comparison of chlorophyll and pheopigment determinations by spectrophotometric, fluorometric, spectrofluorometric and HPLC methods." Marine Microbial Food Webs 4(2): 217-238.

Nicol, S., T. Pauly, et al. (2000). "Ocean circulation off east Antarctica affects ecosystem structure and sea-ice extent." Nature 406(6795): 504-507.

Norberg, J. and D. DeAngelis (1997). "Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrients." Ecological modelling 95(1): 75.

O' Reilly, J. E., S. Maritorena, et al. (2000). Ocean Color Chlorophyll a Algorithms for SeaWiFS, OC2 and OC4: Version 4. Volume 11,SeaWiFS Postlaunch Calibration and
Validation Analyses,Part 3, NASA Goddard Space Flight Center.

Obata, A., J. Ishizaka, et al. (1996). "Global verification of critical depth theory for phytoplankton bloom with climatological in situ temperature and satellite ocean color data." Journal of geophysical research 101(9): 20657.

Odonohue, M. J. H. and W. C. Dennison (1997). "Phytoplankton Productivity Response to Nutrient Concentrations, Light Availability and Temperature Along an Australian Estuarine Gradient." Estuaries 20(3): 521.

Ojala, A. (1993). "Effects of Light and Temperature on the Cell-Size and Some Biochemical-Components in 2 Fresh-Water Cryptophytes." Nordic Journal of Botany 13(6): 697-705.
The effects of light and temperature on cell size and cellular composition (chlorophyll, protein, carbohydrate) of two freshwater cryptophytes were studied with batch cultures. Neither of the species had a constant cell size but the size varied with growth conditions. At each temperature the smallest cells were recorded at the lowest experimental photon flux density. The smallest cells of Cryptomonas 979/67 had an average volume of 232 mum3 and the largest ones 1 020 mum3. In Cryptomonas 979/62 the smallest and largest cells measured 4 306 mum3 and 12 450 mum3. Both species increased their cellular chlorophyll content when PFD dropped below 110-120 mumol m-2 s- 1. The highest and lowest chlorophyll contents of 979/67 were 7.45 fg mum-3 and 0.55 fg mum-3 respectively. For 979/62 the corresponding values were 10.23 fg mum-1 and 0.93 fg mum-3. In both species the protein content remained stable at PFDs higher than 110-120 mumol m-2 s-1. The highest content of protein measured in 979/67 was 638 fg mum-3 and the lowest 147 fg mum- 3. For 979/62 these values were 1 036 fg mum-3 and 148 fg mum-3 respectively. The carbohydrate results were less clear and no pattern either in response to photon flux density or temperature was obvious. The lowest and highest contents recorded for 979/67 were 62 fg mum-3 and 409 fg mum-3 and for 979/62, 36 fg mum-3 and 329 fg mum-3.

Ojala, A., S. I. Heaney, et al. (1996). "Growth of migrating and non-migrating cryptophytes in thermally and chemically stratified experimental columns." Freshwater Biology 35(3): 599-608.
Growth rates of migrating and non-migrating populations of two strains of freshwater cryptophytes, CCAP 979/67 and 979/62, under different light and nutrient regimes were calculated from experiments conducted in laboratory columns which were thermally stratified. During the experiments, cellular carbon, nitrogen, phosphorus, carbohydrate and protein were also analysed. The intention was that the populations would become either phosphorus- or nitrogen-depleted following a period of growth. 2. In all experiments, populations of cryptophytes grew but growth appeared of short duration. In a phosphorus depletion experiment with Cryptomonas 979/67, there was a period of rapid growth starting on day 2 and finishing on day 8, during which the estimated growth rate was c. 0.9 div.day(- 1). In a nitrogen depletion experiment, the period of rapid growth of C. 979/67 lasted only for 2-3 days with a growth rate of c. 0.85 div.day(-1). 3. In a phosphorus depletion experiment with C. 979/62, the onset of a period of rapid growth coincided with the commencement of diel vertical migration. The highest growth rate was estimated as c. 1.0 div.day(-1). In a nitrogen depletion experiment, C. 979/62 did not migrate and attained a growth rate of only 0.28 div.day(-1). 4. For C. 979/67 the highest observed growth rate was lower than the maximum potential growth rate of 1.38 div.day(-1) estimated in batch culture. For C. 979/62 the maximum growth rate in the column was similar to the maximum potential growth rate of 0.87 div.day(-1) in batch culture experiments. 5. The results suggest that some migrating cryptophytes under favourable conditions in stratified water columns can attain high growth rates supporting the hypothesis of Raven & Richardson (1984) that, based on cost-benefit analysis, diel vertical migrations could increase the growth rate of flagellates. Such growth appears of short duration and its ecological importance still requires further verification.

Packard, G. C. and T. J. Boardman (1988). "The misuse of ratios, indices and percentages in ecophysiological research." Physiological Zoology 61(1): 1-9.

Palmisano, A. C., J. B. Soohoo, et al. (1987). "Effects of 4 Environmental Variables on Photosynthesis- Irradiance Relationships in Antarctic Sea-Ice Microalgae." Marine Biology 94(2): 299-306.

Pan, Y. L., D. V. S. Rao, et al. (1996). "Acclimation to low light intensity in photosynthesis and growth of Pseudo-nitzschia multiseries Hasle, a neurotoxigenic diatom." Journal of Plankton Research 18(8): 1427-1438.
Pseudo-nitzschia multiseries, a neurotoxigenic diatom, was grown in batch culture at light intensities between 53 and 1100 mu mol m(-2) s(-1). Cellular contents of carbon, nitrogen and chlorophyll a, and the relationship between photosynthesis and light levels, were studied during exponential (day 4) and stationary phases (day 12). In the stationary phase at low light, there was an increase in cellular chlorophyll a and the initial slope of P-I curves (alpha(B)), which permitted a photosynthetic assimilation of energy equivalent to that of cells grown at high light. In past incidents of domoic acid poisoning, this may have facilitated domoic acid production at low light intensities.

Parkhill, K. L. and J. S. Gulliver (1998). "Application of photorespiration concepts to whole stream productivity." Hydrobiologia 389(1-3): 7-19.

Payri, C. E., S. Maritorena, et al. (2001). "Photoacclimation in the tropical coralline alga Hydrolithon onkodes (Rhodophyta, corallinaceae) from a French Polynesian reef." Journal of Phycology 37: 223-234.

Perry, M., M. Talbot, et al. (1981). "Photoadaptation in marine phytoplankton: response of the photosynthetic unit." Mar. Biol. 62: 91-101.

Peters, E. and D. N. Thomas (1996). "Prolonged darkness and diatom mortality .1. Marine Antarctic species." Journal of Experimental Marine Biology and Ecology 207(1-2): 25-41.
The effect of prolonged periods of darkness (up to 10 months) was investigated in the diatom species Thalassiosira antarctica Comber, T. tumida (Janisch) Hasle, Porosira pseudodenticulata (Hustedt) Joust, Proboscia inermis (Castracane) Jordan and Ligowski and Fragilariopsis kerguelensis (O'Maera) Hustedt isolated from the Southern Ocean. Sudden darkness did not induce resting spore formation. All species survived in their vegetative stage. High levels of photosynthesis were resumed in T. antarctica, T. tumida and P. inermis upon re-exposure to light at all times tested during a 3 month dark period. Cellular chlorophyll a, carbon and nitrogen decreased at the beginning of the dark period and remained more or less stable suggestive of a low maintenance respiration. Species specific survival times varied from less than 4 months up to 9 months. After returning to the former light regime during the species specific survival times T. antarctica, T. tumida, P. pseudodenticulata and P. inermis began growing at rates similar to those in the pre-dark phase.

Platt, T. (1986). "Primary production of the ocean water column as a function of surface light intensity: algorithms for remote sensing." Deep-Sea Research 33(149-163).

Platt, T., C. L. Gallegos, et al. (1980). "Photoinhibition of photosynthesis in natural assemblages of marine phytoplankton." Journal of Marine Research 38: 687-701.

Platt, T. and A. D. Jassby (1976). "The relationship between photosynthesis and light for natural assemblages of coastal marine phytoplankton." J. Phycol. 12: 421-430.

Platt, T. and S. Sathyendranath (1991). "Biological Production Models as Elements of Coupled, Atmosphere-Ocean Models for Climate Research." Journal of Geophysical Research-Oceans 96(C2): 2585-2592.
Process models of phytoplankton production are discussed with respect to their suitability for incorporation into global- scale numerical ocean circulation models. Exact solutions are given for integrals over the mixed layer and the day of analytic, wavelength-independent models of primary production. Within this class of model, the bias incurred by using a triangular approximation (rather than a sinusoidal one) to the variation of surface irradiance through the day is computed. Efficient computation algorithms are given for the nonspectral models. More exact calculations require a spectrally sensitive treatment. Such models exist but must be integrated numerically over depth and time. For these integrations, resolution in wavelength, depth, and time are considered and recommendations made for efficient computation. The extrapolation of the one-(spatial)-dimension treatment to large horizontal scale is discussed.

Post, A. F., Z. Dubinsky, et al. (1984). "Kinetics of light-intensity adaptation in a marine planktonic diatom." Mar. Biol. 83(231-238).

Prezelin, B. B. and R. S. Alberte (1978). "Photosynthetic charateristics and organization of chlorophyll in marine dinoflagellates." Proc. Nat. Acad. Sci. 75: 1801-1804.

Prezelin, B. B. and H. A. Matlick (1980). "Time-course of photoadaptation in the photosynthesis-irradiance relationship of a dinoflagellate exhibiting photosynthetic periodicity." Marine Biology 58: 85-96.

Prezelin, B. B. and B. M. Sweeney (1977). "Characterization of photosynthetic rhythms in marine dinoflagellates. II. Photosynthesis-irradiance curves and in vivo chlorophyll a fluorescence." Plant Physiology 60: 388-392.

Prezelin, B. B., M. M. Tilzer, et al. (1991). "The Control of the Production Process of Phytoplankton by the Physical Structure of the Aquatic Environment with Special Reference to Its Optical-Properties." Aquatic Sciences 53(2-3): 136-186.
This tutorial was designed for nonbiologists requiring an introduction to the nature and general timescales of phytoplankton responses to physical forcing in aquatic environments. As such, an effort was made to highlight biological markers which might assist in identifying, measuring and/or validating physical processes controlling the variability in the distribution, abundance, composition and activity of phytoplankton communities. Given the recent advances in environmental optics and remote sensing capabilities, a special emphasis was placed on the nature and utility of phytoplankton optical properties in current bio- optical modelling efforts to predict temporal and spatial variability in phytoplankton productivity and growth.

Quéguiner, B. and L. Legendre (1986). "Phytoplankton photosynthetic adaptation to high frequency light fluctuations simulating those induced by sea surface waves." Mar. Biol. 90: 483-491.

Rae, R. and W. F. Vincent (1998). "Phytoplankton Production in Subarctic Lake and River Ecosystems: Development of a Photo-synthesis-temperature-irradiance Model." Journal of plankton research 20(7): 1293.

Rakaj, M., F. Hindak, et al. (2000). "Phytoplankton species diversity of the Albanian part of Lake Shkodra in 1998-1999." Biologia 55(4): 329-342.
The results of phytoplankton species diversity studies of the Albanian part of Lake Shkodra in 1998-1999 are presented. Lake Shkodra is the largest lake in the Balkan Peninsula situated transboundary between the Yugoslavian Federal Republic (Montenegro) and Albania. It is a large, but shallow lake of an oligotrophic character. In material collected from 9 sampling stations altogether 142 genera with 455 species and infraspecific taxa were determined; majority of them (255) have not been recorded in the Montenegro part of Lake Shkodra by PETKOVIC (1981). The highest number of species and infraspecific taxa were found in Bacillariophyceae (242) and Chlorophyceae (97), followed by Conjugatophyceae (35), Euglenophyceae (35) and Cyanophyceae (24); other groups were represented only by some taxa. In spite of a relatively rich phototrophic microflora, Lake Shkodra according to the phytoplankton species composition can be classified oligotrophic. Diatoms dominated in most samples, with Cyclotella ocellata, C. distinguenda, Asterionella formosa, Fragilaria ulna, Aulacoseira ambigua, Cymbella affinis, Gomphonema acuminatum, Navicula capitatoradiata. From other algal groups belonged to the characteristic species of Lake Shkodra phytoplankton: Ceratium hirundinella from Dinophyta, Dinobryon sociale and D. divergens from Chrysophyceae, Merismopedia glauca, Microcystis aeruginosa and Radiocystis aphanothecoidea from Cyanophyta, Pediastrum simplex, P. duplex var. gracillimum, Coelastrun polychordum, and Scenedesmus perforatus from Chlorophyceae.

Ramus, J. (1990). "A Form-Function Analysis of Photon Capture for Seaweeds." Hydrobiologia 204: 65-71.

Raven, J. A. (1991). "Physiology of inorganic C acquisition and implications for resource use efficiency by marine phytoplankton: relation to increased CO2 and temperature: commissioned review." Plant, cell and environment 14(8): 779.

Raven, J. A., A. M. Johnston, et al. (1993). "Influence of changes in CO2 concentration and temperature on marine phytoplankton 13C/12C ratios: an analysis of possible mechanisms." Global and planetary change 8(1/2): 1.

Ravens, T. M., O. Kocsis, et al. (2000). "Small-scale turbulence and vertical mixing in Lake Baikal." Limnol. Oceanogr. 45(1): 159-173.

Richardson, K., J. Beardall, et al. (1983). "Adaptation of unicellular algae to irradiance: an analysis of strategies." New Phytol. 93: 157-171.

Richardson, T. L., C. E. Gibson, et al. (2000). "Temperature, growth and seasonal succession of phytoplankton in Lake Baikal, Siberia." Freshwater Biology 44(3): 431-440.
1. Growth rates of two dominant Lake Baikal phytoplankton, the winter diatom Aulacoseira baicalensis and the summer cyanobacterium Synechocystis limnetica, were measured in the laboratory under varied temperature and light regimes to determine the potential role of these abiotic factors in seasonal species succession in the lake. 2. Aulacoseira baicalensis grew best at low temperature and not at all above 8 degrees C. Its maximum instantaneous growth rate was 0.15 d(-1) recorded at 2-3 degrees C. Cells grew faster as temperature decreased, apparently in contrast to conventional Q(10)-based temperature-growth relationships. 3. The picoplankter Synechocystis limnetica did not grow at 2-3 or 5-6 degrees C, but grew at a rate of 0.24 d(-1) at the highest incubation temperature of 17 degrees C. Maximum growth rate was 0.35 d(-1) at 8 degrees C. 4. Saturation irradiances (I-k) for growth of Aulacoseira baicalensis and Synechocystis limnetica were near pre-acclimation values of 40 mu mol m(-2) S-1. At temperatures conducive to growth, both phytoplankters grew at all irradiances tested, except for A. baicalensis which would not grow at values above 300 mu mol m(-2) s(-1) at 8 degrees C. 5. We conclude that temperature is a major driving force for the seasonal succession of species in Lake Baikal. Other factors, including vertical mixing of the water column and grazing by zooplankton, may also play important roles.

Riegman, R. and F. Colijn (1991). "Evaluation of Measurements and Calculation of Primary Production in the Dogger Bank Area (North-Sea) in Summer 1988." Marine Ecology-Progress Series 69(1-2): 125-132.
Primary production was measured during a survey in the Dogger Bank area, where both stratified and non-stratified conditions existed in July-August 1988. Daily primary production was calculated, based on C-14-fixation rates in an incubator with an artificial light source, depth profiles of in situ irradiance, and vertically heterogeneous phytoplankton distributions. Values ranged among stations from 300 to 2200 mg C m-2 d-1. Average primary production in the Dogger Bank area was estimated at 1.2 g C m-2 d-1. Variation in cloudiness affected primary production by a factor of 4.5. Calculations based on surface samples alone showed an average areal primary production underestimate of 17 %. After correction for the uneven vertical biomass distribution, primary production was still underestimated by 12 % as a result of photoadaption. Especially below 30 m, I(k) was reduced from 310 to 174-mu-E m- 2 s-1, demonstrating the presence of shade-adapted phytoplankton at the thermocline. Calculated daily primary production rates based on in situ incubations and on incubator measurements deviated by only 5%. Light quality did not have a significant effect on water column productivity. Size- dependent primary production based on post-incubation filtration onto 5-mu-m filters showed that, on average, 84 % of total primary production was in the > 5-mu-m fraction.

Riisgard, H. U., G. Quinn, et al. (2000). "The peer-review system: time for re-assessment?" Marine Ecology-Progress Series 192: 305-313.
Referees are the backbone of quality control. They need more recognition for their work. In an open exchange of opinions among a number of leading editors and experienced reviewers one suggestion has wide support: It should no longer be 'free' to submit a manuscript to a scientific journal. While cash payment for reviews is not considered a good idea, a 'payback in kind' system is favored: i.e., if you want to submit papers to a journal you must be willing to review for that journal.

Rmiki, N. E., C. Brunet, et al. (1996). "Xanthophyll-cycle and photosynthetic adaptation to environment in macro- and microalgae." Hydrobiologia 327: 407-413.
Microalgae and macrophytes adapt their pigment content to the environment because excessive light could limit their photosynthetic rate by inducing photoinhibition. Carotenoids participate in the photoadaptative response especially through the operation of xanthophyll cycles (violaxanthin-zeaxanthin or diadinoxanthin-diatoxanthin). An increasing gradient of diatoxanthin in phytoplankton chromophytes is found from the inshore to the offshore waters, less turbid in relation to the different light penetration in seawater. In addition, a nyctemeral cycle is noted, with a suppression of diatoxanthin at night and its accumulation with the increase of the light. Similarly the vertical distribution, on the French Brittany coasts, of several Gracilaria and Gracilariopsis species corresponds to increasing zeaxanthin amounts in the seaweeds living at the upper zones, which are more resistant to photoinhibition as shown by fluorescence and oxygen evolution analysis. An operating xanthophyll cycle should be regarded as a regulatory mechanism involved in stress response for the dissipation of excessive excitation energy through de- epoxidated xanthophylls such as zeaxanthin or diatoxanthin.

Robarts, R. D., M. S. Evans, et al. (1992). "Light, nutrients, and water temperature as determinants of phytoplankton production in two saline, prairie lakes with high sulphate concentrations." Canadian journal of fisheries and aquatic scienc 49(11): 2281.

Rodrigues, M. A., C. P. dos Santos, et al. (2000). "Photosynthetic light-response curves and photoinhibition of the deep-water Laminaria abyssalis and the intertidal Laminaria digitata (Phaeophyceae)." Journal of Phycology 36(1): 97-106.

Rowan, K. S. (1989). Photosynthetic Pigments of Algae. New York, NY, Press Syndicate - University of Cambridge.

Sacksteder, C. and B. A. Barry (2001). "Fourier transform infrared spectroscopy: a molecular approach to an organismal question." J. Phycol. 37(2): 197-199.

Sagert, S. and H. Schubert (2000). "Acclimation of Palmaria palmata (Rhodophyta) to light intensity: comparison between artificial and natural light fields." J. Phycol. 36(6): 1119-1128.
The acclimation of the photosynthetic apparatus of Palmaria palmata (L.) to light intensity was examined in the field and under laboratory conditions. Algae from 3 different shore levels and from laboratory cultures adapted to 6 different photon flux densities were compared. This was done on the basis of light doses, which were delivered by different light regimes in the field and in the laboratory. Laboratory samples were adjusted to constant photon flux densities between 7 and 569 mol photonsm-2s-1 in a 16:8 light:dark photoperiod. Under field conditions the daily amplitudes reached up to approximately 2000 mol photonsm-2s-1 within a natural daily light course. Over the course of 14 days the light doses resulting from those different regimes are similar for both treatments. An increasing growth rate per day with increasing light doses was observed in the laboratory. Growth was saturated at 113 mol photonsm-214 d-1. Light saturation points (Ek) of photosynthesis increased with increasing light doses for both field and laboratory samples, and all Ek values were significantly related to the growth light dose. A correlation between fresh weight-related lutein content and growth light dose was found for laboratory samples only, whereas the lutein:chlorophyll a (chl a) ratio was strongly correlated with Ek for laboratory and field samples. The content of chl a and phycoerythrin (PE) per fresh weight decreased significantly with increasing light doses under field conditions. Simultaneously, the PE:chl a ratio increased, whereas this ratio was not influenced by laboratory treatments. The correspondence of Ek values for field and laboratory treatments indicated that they were affected mainly by light dose. However, the variability in pigmentation was mainly dependent on temporal variability in light intensity (the amplitude of variations in incident light).

Sakshaug, E., A. Bricaud, et al. (1997). "Parameters of photosynthesis: definitions, theory and interpretation of results." Journal of Plankton Research 19(11): 1637-1670.
A global assessment of carbon flux in the world ocean is one of the major undertakings of the Joint Global Ocean Flux Study (JGOFS). This has to be undertaken using historical in situ data of primary productivity. As required by the temporal and spatial scales involved in a global study, it can be conveniently done by combining, through appropriate models, remotely sensed information (chlorophyll a, temperature) with basic information about the parameters related to the carbon uptake by phytoplanktonic algae. This requires a better understanding as well as a more extended knowledge of these parameters which govern the radiative energy absorption and utilization by algae in photosynthesis. The measurement of the photosynthetic response of algae [the photosynthesis (P) versus irradiance (E) curves], besides being less shiptime consuming than in situ primary production experiments, allows the needed parameters to be derived and systematically studied as a function of the physical, chemical and ecological conditions. The aim of the present paper is to review the sig nificance of these parameters, especially in view of their introduction into models, to analyze the causes of their variations in the light of physiological considerations, and finally to provide methodological recommendations for meaningful determinations, and interpretation, of the data resulting from P versus E determinations. Of main concern are the available and usable irradiance, the chlorophyll a-specific absorption capabilities of the algae, the maximum light utilization coefficient (alpha), the maximum quantum yield (phi(m)), the maximum photosynthetic rate (P-m) and the light saturation index (E-k) The potential of other, non-intrusive, approaches, such as the stimulated variable fluorescence, or the sun-induced natural fluorescence techniques is also examined.

Sakshaug, E. and D. A. Kiefer (1989). "A steady state description of growth and light absoprtion in the marine planktonic diatom Skeletonema costatum." Limnol. Oceanogr. 34(1): 198-205.

Salencon, M. J. and J. M. Thebault (1996). "Simulation model of a mesotrophic reservoir (Lac de Pareloup, France): melodia, an ecosystem reservoir management model." Ecological Modelling 84(1): 163-187(25).

Satpathy, K. K. and K. V. K. Nair (1996). "Occurrence of phytoplankton bloom and its effect on coastal water quality." Oceanographic Literature Review 43(12): 1238-1239(2).

Sayer, C. D. (2001). "Problems with the application of diatom-total phosphorus transfer functions: examples from a shallow English lake." Freshwater Biology 46(6): 743-757(15).

Schulze, P. C. and A. S. Brooks (1987). "The Possibility of Predator Avoidance by Lake-Michigan Zooplankton." Hydrobiologia 146(1): 47-55.

Schulze, P. C. and A. S. Brooks (1987). "The Possibility of Predator Avoidance by Lake-Michigan Zooplankton." Hydrobiologia 146(1): 47-55.

Schwab, D. (2000). "Personal communication."

Schwab, D. J. and J. R. Bennett (1987). "Lagrangian Comparison of Objectively Analyzed and Dynamically Modeled Circulation Patterns in Lake Erie." Journal of Great Lakes Research 13(4): 515-529.

Schwab, D. J., A. H. Clites, et al. (1989). "The Effect of Wind on Transport and Circulation in Lake St Clair." Journal of Geophysical Research-Oceans 94(C4): 4947-4958.

Schwab, D. J., G. A. Leshkevich, et al. (1999). "Automated mapping of surface water temperature in the Great Lakes." Journal of Great Lakes Research 25(3): 468-481.
A procedure for producing daily cloud-free maps of surface water temperature in the Great Lakes has been developed. It is based on satellite-derived AVHRR (Advanced Very High Resolution Radiometer) imagery from NOAA's Coast Watch program. The maps have a nominal resolution of 2.6 km and provide as complete as possible coverage of the Great Lakes on a daily basis by using previous imagery to estimate temperatures in cloud covered areas. Surface water temperature estimates derived from this procedure compare well with water temperatures measured at the eight NOAA weather buoys in the lakes. The mean difference between the buoy temperature and the satellite-derived temperature estimates is less than 0.5 degrees C for all buoys. The root mean square differences range from 1.10 to 1.76 degrees C. As one example of the possible applications of this product, the daily surface water temperature maps for 1992 to 1997 were analyzed to produce daily estimates of average surface water temperature for each lake. Results are compared to the long-term (28 year) mean annual cycle of average surface water temperatures. The average surface water temperatures vary from as much as 4 degrees C below climatology in 1993 to 2 to 3 degrees C above climatology in 1995. The new analysis procedure also provides a more realistic depiction of the spatial distribution of temperature in the springtime than the climatological maps.

Smith, T. M., R. W. Reynolds, et al. (1996). "Reconstruction of historical sea surface temperatures using empircale orthogonal functions." Journal of Climate 9(June): 1403-1420.

Smol, J. P. and B. F. Cumming (2000). "Tracking long-term changes in climate using algal indicators in lake sediments." J. Phycol. 36(6): 986-1011.
Interest in climate change research has taken on new relevance with the realization that human activities, such as the accelerated release of the so-called greenhouse gases, may be altering the thermal properties of our atmosphere. Important social, economic, and scientific questions include the following. Is climate changing? If so, can these changes be related to human activities? Are episodes of extreme weather, such as droughts or hurricanes, increasing in frequency? Long-term meteorological data, on broad spatial and temporal scales, are needed to answer these questions. Unfortunately, such data were never gathered; therefore, indirect proxy methods must be used to infer past climatic trends. A relatively untapped source of paleoclimate data is based on hindcasting past climatic trends using the environmental optima and tolerances of algae (especially diatoms) preserved in lake sediment profiles. Paleophycologists have used two approaches. Although still controversial, attempts have been made to directly infer climatic variables, such as temperature, from past algal assemblages. The main assumption with these types of analyses is that species composition is either directly related to temperature or that algal assemblages are related to some variable linearly related to temperature. The second more commonly used approach is to infer a limnological variable (e.g. water chemistry, lake ice cover, etc.) that is related to climate. Although paleolimnological approaches are broadly similar across climatic regions, the environmental gradients that paleophycologists track can be very different. For example, climatic inferences in polar regions have focused on past lake ice conditions, whereas in lakes near arctic treeline ecotones, paleophycologists have developed methods to infer past lakewater-dissolved organic carbon, because this variable has been linked to the density of coniferous trees in a drainage basin. In closed-basin lakes in arid and semiarid regions, past lakewater salinity, which can be robustly reconstructed from fossil algal assemblages, is closely tied to the balance of evaporation and precipitation (i.e. drought frequency). Some recent examples of paleophycolgical work include the documentation of striking environmental changes in high arctic environments in the 19th century believed to be related to climate warming. Meanwhile, diatom-based reconstructions of salinity (e.g. the Great Plains of North America and Africa) have revealed prolonged periods of droughts over the last few millennia that have greatly exceeded those recorded during recent times. Marked climatic variability that is outside the range captured by the instrumental record has a strong bearing on sustainability of human societies. Only with a long-term perspective can we understand natural climatic variability and the potential influences of human activities on climate and thereby increase our ability to understand future climate.

Sokal, R. R. and F. J. Rohlf (1981). Biometry: the principles and practice of statistics in biological research.

Stauber, J. L. and S. W. Jeffrey (1988). "Photosynthetic Pigments in 51 Species of Marine Diatoms." Journal of Phycology 24(2): 158-172.

Stramski, D. (1999). "Refractive index of planktonic cells as a measure of cellular carbon and chlorophyll a content." Deep Sea Research Part I: Oceanographic Research Papers 46(2): 335-351(17).

Stramski, D., G. Rosenberg, et al. (1993). "Photosynthetic and Optical-Properties of the Marine Chlorophyte Dunaliella-Tertiolecta Grown under Fluctuating Light Caused by Surface-Wave Focusing." Marine Biology 115(3): 363-372.
Photosynthetic and optical properties of the marine chlorophyte Dunaliella tertiolecta Butcher were studied in response to irradiance fluctuations caused by surface-wave focusing. The experimental conditions simulated the prominent features of the light field (high average irradiance, spectral composition and statistical properties) in the uppermost few meters of the water column under sunny surface conditions. The properties of algae grown under high-frequency fluctuations were compared with control cells grown under constant light at the same average irradiance (approximately 800 mumol quanta m-2 s-1). No significant differences were found for a number of parameters, including growth rate, cellular chlorophyll a and pigment ratios, photosynthetic unit size and density of Photosystem I reaction centers, the rate of photosynthesis at the growth irradiance, dark respiration, and in vivo fluorescence of chlorophyll a per cell. Photosynthetic parameters were not affected by whether the incident light for oxygen exchange measurements was fluctuating or constant. This was the case whether the cells had been previously acclimated to either fluctuating or constant irradiance. Such a photosynthetic response indicates that cells are accomplishing a time integration of the fluctuating light. In addition, although D. tertiolecta is capable of dramatically changing its optical properties in response to low or high growth irradiance levels, the refractive index of the cells, the efficiency factors for light absorption and scattering by individual cells, and chlorophyll-specific absorption and scattering coefficients of cell suspensions, were all very similar under high irradiance, whether or not wave focusing was present.

Strickland, J. D. H. and T. R. Parsons (1972). "A practical handbook of seawater analysis." Bull. Fish. Res. Board Can. 167: 201.

Strutton, P. G., F. B. Griffiths, et al. (2000). "Primary productivity off the coast of East Antarctica (80-150 degrees E): January to March 1996." Deep-Sea Research Part Ii-Topical Studies in Oceanography 47(12-13): 2327-2362.

Stuart, V., S. Sathyendranath, et al. (2000). "Bio-optical characteristics of diatom and prymnesiophyte populations in the Labrador Sea." Marine Ecology-Progress Series 201: 91-106.

Sukenik, A., J. Bennett, et al. (1987). "Light-Saturated Photosynthesis - Limitation by Electron- Transport or Carbon Fixation." Biochimica Et Biophysica Acta 891(3): 205-215.

Sukenik, A., J. Bennett, et al. (1988). "Changes in the Abundance of Individual Apoproteins of Light- Harvesting Chlorophyll-a/B-Protein Complexes of Photosystem-I and Photosystem-Ii with Growth Irradiance in the Marine Chlorophyte Dunaliella-Tertiolecta." Biochimica Et Biophysica Acta 932(2): 206-215.

Sukenik, A., J. Bennett, et al. (1987). "The Molecular-Basis of Photoadaptation in the Marine Chlorophyte Dunaliella-Tertiolecta." Israel Journal of Botany 36(1): 50-50.

Sukenik, A., J. Bennett, et al. (1990). "Adaptation of the Photosynthetic Apparatus to Irradiance in Dunaliella-Tertiolecta - a Kinetic-Study." Plant Physiology 92(4): 891-898.

Sukenik, A., P. G. Falkowski, et al. (1987). "Potential Enhancement of Photosynthetic Energy-Conversion in Algal Mass-Culture." Biotechnology and Bioengineering 30(8): 970-977.

Sukenik, A., P. G. Falkowski, et al. (1989). "Energy-Transfer in the Light-Harvesting Complex-Ii of Dunaliella-Tertiolecta Is Unusually Sensitive to Triton-X-100." Photosynthesis Research 21(1): 37-44.

Sukenik, A., K. D. Wyman, et al. (1987). "A Novel Mechanism for Regulating the Excitation of Photosystem- Ii in a Green-Alga." Nature 327(6124): 704-707.

Terzic, S., M. Ahel, et al. (1998). "Phytoplankton pigment signatures in the Gulf of Trieste related to major freshwater inputs during 1992." Periodicum Biologorum 100(1): 105-111.
Background and purpose: Photosynthetic pigments are useful biomarkers of abundance, composition and physiological status of the phytoplankton biomass in the marine environment. The scope of our study was to investigate phytoplankton dynamics reflected by seasonal variability of pigment biomarkers in a temperate region characterised by significant and seasonally variable freshwater inputs. Materials and methods: Chlorophyll and carotenoid pigments, as well as breakdown products of chlorophyll a were determined by using reversed phase high- performance liquid chromatography (RP HPLC) equipped with serially coupled spectrophotometric and spectrofluorimetric detectors. Results: Chlorophyll a concentrations varied mostly between 100 and 2000 ng/l with maxima clearly related to major freshwater inputs. The most prominent accessory pigments were fucoxanthin, 19'-hexanoyloxyfucoxanthin and chlorophyll b, varying in ranges 20-1200 ng/l, 5-360 ng/l and 1-780 ng/l, respectively This indica ted dia tome, prymnesiophytes and green algae as the most abundant phytoplankton groups. Other minor taxonomic marker pigments in eluded 19'-butanoyloxy- fucoxanthin, peridinin and zeaxanthin/lutein. The major nutrient input by rivers and rain in March/April was followed by a large increase of diatoms (fucoxanthin). Depletion of orthosilicate and nitrate in late spring caused a decline of the diatom bloom and : resulted in a shift in dominant phytoplankton from diatoms to small flagellates. This was reflected by a significant decrease in the fucoxanthin/19'- hexano-yloxyfucoxanthin ratio from 5-29 to 0.2-1. Prymnesiophytes and diatoms dominated the phytoplankton throughout the whole summer while intense rain during the autumn overturn induced a concomitant increase oidia toms (fucoxanthin) and green algae (chlorophyll b). 4Conclusion: Photosynthetic pigment composition reflected clearly the impact of major freshets on the seasonal dynamics of phytoplankton in the Gulf of Trieste. Compared with the conventional light- microscopy chemotaxonomic approach provided a more detailed insight into the corn position of nanoplankton and indica ted prymnesiophytes and green algae as the major constituents of phytoplankton biomass.

Therriault, J. C., D. Booth, et al. (1990). "Phytoplankton photoadaptation to vertical excursion as estimated by an in vivo fluorescence ratio." Marine Ecology-Progress Series 60: 97-111.

Thompson, P. A., M. Guo, et al. (1992). "Effects of variation in temperature. II. On the fatty acid composition of eight species of marine phytoplankton." Journal of phycology 28(4): 488.

Thompson, P. A., M. Guo, et al. (1992). "Effects of variation in temperature. I. On the biochemical composition of eight species of marine phytoplankton." Journal of phycology 28(4): 481.

Tillmann, U., K. J. Hesse, et al. (2000). "Planktonic primary production in the German Wadden Sea." Journal of Plankton Research 22(7): 1253-1276.

Torres, M., F. X. Niell, et al. (1991). "Photosynthesis of Gelidium sesquipedale: effects of temperature and light on pigment concentration, C/N ratio and cell-wall polysaccharides." Hydrobiologia 221: 77.

Trabalon, M., G. Pourie, et al. (1998). "A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments." Deep Sea Research Part II: Topical Studies in Oceanography 45(10): 2133-2170(38).

Tremblay, J. E., B. Klein, et al. (1997). "Estimation of f-ratios in oceans based on phytoplankton size structure." Limnology and Oceanography 42(3): 595-601.
Several equations to estimate the vertical export of particulate organic carbon from the ocean's euphotic zone (POC,) use variables that are determined at sea or are derived from remote sensing. One of the approaches requires reliable estimates off-ratios (NO3- uptake/total N uptake) that can be either determined directly from N uptake by phytoplankton or derived from total phytoplankton Chi a biomass or production (P-T) or from NO3- concentrations. By using a combination of theoretical considerations and field measurements, we show that f-ratios are linear functions of size-fractionated (>5 mu m/total) phytoplankton production (P-L/P-T) and biomass. Comparison of our model with the more usual f-ratio = f(P-T) shows that the large residuals are spread over the range of P- L/P-T in the former, whereas they are concentrated at low P-T in the latter. Because P-T is low in most of the world oceans most of the time, use of our model may significantly improve the estimates off-ratio and thus of POCE.

Trevena, A. J., G. B. Jones, et al. (2000). "Profiles of DMSP, algal pigments, nutrients and salinity in pack ice from eastern Antarctica." Journal of Sea Research 43(3-4): 265-273.
Concentrations of dimethylsulphoniopropionate (DMSP) were measured in seven pack ice cores from three sites in eastern Antarctica to determine their relation to algal pigments, nutrients (nitrate, silicate and phosphate) and bulk salinity. The algal groups haptophytes, dinoflagellates and diatoms were identified in surface, interior and bottom assemblages in the pack ice cores using the photosynthetic marker pigments 19'- hexanoyloxyfucoxanthin (HEX), peridinin (PER) and fucoxanthin (FUC), respectively. DMSP concentrations were significantly correlated (P < 0.01, Pearson) with chlorophyll-a (r = 0.58), HEX (r = 0.75), PER (r = 0.79) and FUC (r = 0.63) concentrations. The pool of DMSP within the pack ice (mean 107 nM) was contributed mainly by interior and bottom algal assemblages (mean 94 and 268 nM, respectively), whilst the surface algal assemblages were minor contributors (mean 18 nM). DMSP production and/or accumulation appears to differ between surface, interior and bottom pack ice algal assemblages due to differences in biomass, class composition, and possibly the unique environmental conditions experienced by each assemblage. In pack ice, diatoms appear to be important producers of DMSP, due to their dominance of algal assemblages. (C) 2000 Elsevier Science B.V. All rights reserved.

Tuji, A. (2000). "The effect of irradiance on the growth of different forms of freshwater diatoms: Implications for succession in attached diatom communities." Journal of Phycology 36(4): 659-661.

van der Heever, J. A. and J. U. Grobbelaar (1998). "In vivo chlorophyll A fluorescence of Selenastrum capricornutum as a screening bioassay in toxicity studies." Archives of Environmental Contamination and Toxicology 35(2): 281-286.
A method for the estimation of the effect of specific toxins on phytoplankton photosynthesis tinder of toxicity) was investigated using in vivo chlorophyll a fluorescence. No meaningful results were obtained with the following substances; copper, cadmium, mercury, and gusathion, within a 4-h exposure period. It can, therefore, be concluded that in vivo chlorophyll a fluorescence an not a simple bioassay tool, due to the complexity of its origins, but a complex research tool.

van Leeuwe, M. A. and H. J. W. De Baar (2000). "Photoacclimation by the Antarctic flagellate Pyramimonas sp (Prasinophyceae) in response to iron limitation." European Journal of Phycology 35(3): 295-303.
In this study we tested the hypothesis that iron limitation suppresses photoacclimation in cultures of the Antarctic flagellate Pyramimonas sp. The cultures were exposed to two different irradiances under iron-rich and iron-poor conditions. Light-harvesting capacity was determined by assessing the pigment composition and measuring in vivo absorption spectra. Light utilization efficiency (alpha) was determined from photosynthesis versus irradiance curves. The quantum yield of photosynthesis (phi (m)) was calculated using alpha and the absorption spectra. Iron limitation led to commonly observed changes in cells of Pyramimonas, that is, a decrease in cellular pigment content and a reduction in cellular carbon and nitrogen quota. A reduction in alpha (cell) followed a decrease in phi (m) and light-harvesting capacity. interpretation of the effects of iron limitation was different when considered on a carbon basis. Because iron limitation resulted in a decrease in cellular carbon content, the carbon-specific absorption coefficient was not affected. Consequently, the observed decrease in alpha (C) was mainly due to the decrease in phi (m), showing that iron limitation did not control light utilization via pigment synthesis but exerted control on energy transfer. This is supported by the findings that at high irradiance a shift in pigment ratios within the total pool of violaxanthin, antheraxanthin and zeaxanthin towards zeaxanthin, which is indicative of photoacclimation to high irradiance, was observed for iron-replete cells as well as for iron-depleted cells. In contrast to what is generally hypothesized, the effects of iron limitation were not enhanced at low irradiance. Low irradiance led to an increase in the cellular light- harvesting pigment content. This increase was less pronounced in iron-depleted cells than in iron-replete cells. However, looking at the light-harvesting capacity of the cells on a carbon basis, it was found that iron-depleted cells responded similarly to iron-replete cells. We therefore conclude that the light-harvesting capacity was governed by light conditions and not by iron limitation. In addition to the increase in absorption capacity at low irradiance, an increase in light utilization efficiency was measured, again under both iron-rich and iron-poor conditions. Notably, the relative increase in alpha (C) was strongest in iron-depleted cells. Photoacclimation was clearly demonstrated by normalizing alpha to chl alpha. For iron-replete cells, alpha (chl) was highest at high irradiance. In contrast, for iron-depleted cells alpha (chl) was highest at low irradiance. We argue that iron- depleted cells can photoacclimate to low irradiance by a reduction in the 'package effect' and reducing growth rates.

vanderHeever, J. A. and J. U. Grobbelaar (1997). "The use of oxygen evolution to assess the short-term effects of toxicants on algal photosynthetic rates." Water Sa 23(3): 233-237.
O-2-production using either Selenastrum capricornutum or Chlorella vulgaris as indicator organisms to assess the presence or not of toxic compounds, was measured in a small volume oxygen chamber. These measurements were done at predetermined I-k irradiancies. At EC50 and EC90 levels, the response of S. capricornutum and C. vulgaris to atrazine toxicity was opposite to the response as determined at the EC10 level. Chlorella vulgaris is more sensitive than S. Capricornutum to high atrazine concentrations, but S. capricornutum is more sensitive than C. vulgaris at the EC10 level. It was shown that the heavy metals Hg, Cd and Cu and the herbicide, atrazine, influenced the photosynthetic rates but the organophosphate, gusathion, had no effect. The oxygen evolution assay may be useful as a rapid prelimiary screening method for the presence or absence of toxic substances.

Vandevelde, T., L. Legendre, et al. (1989). "Circadian Variations in Photosynthetic Assimilation and Estimation of Daily Phytoplankton Production." Marine Biology 100(4): 525-531.

vanDuin, E. H. S., R. H. Aalderink, et al. (1995). "Light adaptation of Oscillatoria agardhii at different time scales." Water Science and Technology 32(4): 35-48.
The Markermeer is a eutrophic shallow wind exposed lake. In contrast to other eutrophic lakes in the area persistent blooms of the cyanobacterium Oscillatoria agardhii do not occur. The severe variations in the available light energy, caused by an excessive resuspension of sediment, are held responsible for this absence. Field experiments were conducted in the Markermeer, to investigate the relations between O. agardhii and the specific Light climate in the Markermeer, emphasizing the adaptation rate and extent to light energy level variations. In experiments with traditional light and dark bottles, and bottles moving up and down the water column it was observed that vertical mixing tended to increase the net production of oxygen, as the exposure time near the water surface is too short to cause light inhibition. From experiments with a vertical perspex tube it was concluded that during days with maximum hourly light energy levels above 200 mu E . m(-2). s(-1), the light utilization efficiency was much higher in the morning hours than during the afternoon. This phenomenon did usually not occur at days with lower mean irradiance levels. After prolonged periods of low energy levels (below 50 mu E . m(-2). s(-1)), the light utilization efficiency increases significantly but the maximum production level does not increase.

Videau, C., M. Ryckaert, et al. (1998). "Phytoplankton in the Bay of Seine (France). Influence of the river plume on primary productivity." Oceanologica Acta 21(6): 907-921(15).

Vidussi, F., J. C. Marty, et al. (1999). "Phytoplankton pigment variations during the transition from spring bloom to oligotrophy in the northwestern Mediterranean sea - separation of chlorophyll a from divinyl-chlorophyll a and zeaxanthin from lutein." Deep Sea Research Part I: Oceanographic Research Papers 47(3): 423-445(23).

Vincent, W. F., N. Bertrand, et al. (1994). "Photoadaptation to Intermittent Light across to St-Lawrence Estuary Fresh-Water-Saltwater Transition Zone." Marine Ecology-Progress Series 110(2-3): 283-292.
We evaluated 2 competing hypotheses for the photoadaptive characteristics of phytoplankton distributed across the turbid freshwater-saltwater transition zone (TZ) of the St. Lawrence River (Canada): that the communities were photosynthetically adapted to a low mean water column irradiance, or that they were adapted to intermittent exposure to near-surface irradiance conditions. Two cruises were undertaken in spring- early summer, a period that corresponded to major seasonal changes in the optical environment of the St. Lawrence River. There was a large increase in chlorophyll a (chl a) concentration, maximum photosynthetic rates (P(max)B), and the light saturation parameter (I(k)) between the 2 cruises. During this period the nanoplankton (cells in the size range 2 to 20 mum) rose from 33 to 69 % of total chl a. There were no major shifts in photosynthetic characteristics across the transition from freshwater to turbid saltwater conditions, but rather the cells maintained high values of P(max)B and I(k), with low alpha (the light limitation parameter) and little inhibitory response to high photon fluence rates. These observations support the hypothesis that the phytoplankton community in this and perhaps other turbid environments are photoadapted to 'intermittent sun' conditions, rather than the 'shade environment' experienced on average through the water column.

Wagner, A. and N. Kamjunke (2001). "Reduction of the filtration rate of Daphnia galeata by dissolved photosynthetic products of edible phytoplankton." Hydrobiologia 442(1-3): 165-176.
The filtration rate of Daphnia galeata was determined in in situ experiments in Bautzen Reservoir and in laboratory experiments, where daphnids were exposed to filtrates that previously contained either natural phytoplankton or cultured eukaryotic algae (Scenedesmus obliquus or Asterionella formosa), respectively. Individual filtration rate (FR) was measured using fluorescent beads, taking into account ingested beads in the gut only. Compared to heated control treatments (100 degreesC), dissolved compounds released by the nutritious cultured algae during the preconditioning phase or by the natural phytoplankton assemblages from Bautzen Reservoir strongly reduced the filtration rate of D. galeata (down to 60%). Heating deactivated these dissolved compounds. A significant correlation was found between primary production measured in situ and the reduction of FR in the filtrate of reservoir water, indicating that extra-cellular products released during photosynthesis triggered the reduction of the filtration rate. The ratio of ingested to collected beads was used to quantify the proportion of food, which was not only collected but passed the mouth of D. galeata. The ratio of ingestion to collection was compared between filtered and unfiltered reservoir water both media identical with respect to the concentration of dissolved compounds, whereas other factors (e.g. food concentration, temperature, filtration rate) were different. The changes in this ratio between filtered and unfiltered reservoir water suggest that D. galeata is capable of a chemosensory control of the ingestion behaviour by detecting external metabolites.

Wainman, B. C. and D. R. S. Lean (1996). "A comparison of photosynthate allocation in lakes." Journal of Great Lakes Research 22(4): 803-809.
We compared the relationships between photosynthate allocation to protein, carbohydrate, lipid and low molecular weight (LMW) fractions and the variables daylength and water temperature in Lakes Huron, Michigan, and Ontario as well as three smaller headwater lakes in the Lake Ontario drainage. In all lakes investigated the allocation of recently produced photosynthate to carbohydrate was strongly related to daylength (% carbohydrate = -3.5 * daylength (hr) + 72.8; n = 59, r(2) = 0.56). The percentage of photosynthate allocated to protein was a function of water temperature in all lakes although the gamma-intercept for the protein-temperature relationship was much lower in the three headwater lakes and Lake Ontario (% protein = 0.50 * temperature (degrees C) + 6.1; n = 37, r(2) = 0.52) than in Lake Huron and Lake Michigan (% protein = 0.68 * temperature (degrees C) + 24.2; n = 23, r(2) = 0.49). The increase in allocation to protein was related to a decrease in allocation to low molecular weight material (% LMW = -1.1 * % protein + 57.13; n = 60, r(2) = 0.72). The percentages of photosynthate in lipid and LMW material were not related to any of the environmental variables measured. Assuming that photosynthate allocation is related to biochemical composition, the phytoplankton in Lakes Huron and Michigan were more protein rich for a given temperature than those in Lake Ontario and in the smaller inland lakes. The protein deficit was due to an increase in allocation to LMW material.

Wallace, B. B., D. P. Hamilton, et al. (1996). "Response of photosynthesis models to light limitation." Internationale Revue Der Gesamten Hydrobiologie 81(2): 315-324.
An investigation into the effect of rime step on a common photosynthesis algorithm reveals that the predicted phytoplankton production and biomass depend strongly on the length of the time step. This time step dependence is due to the assumption that a light limitation factor derived From integrating the irradiance over the time step is equivalent to the integrated light limitation factor over the time step. This subtle inaccuracy in defining the factor For light limited phytoplankton production produces a substantial difference in the biomass estimates derived from the two models. To illustrate the difference, the light limitation factor integrated over the time step is implemented in the one dimensional water quality model DYRESM-WQ. The new version of DYRESM-WQ is used to simulate chlorophyll a concentrations in Prospect Reservoir, New South Wales. These results are compared to concentrations predicted using the original algorithm. The comparison shows that the new algorithm for phytoplankton production is relatively insensitive to time step, which decreases the difficulty of calibrating the model for chlorophyll a.

Walsby, A. E. (1997). "Modelling the daily integral of photosynthesis by phytoplankton: its dependence on the mean depth of the population." Hydrobiologia 349: 65-74.
Detailed descriptions have been made of the under water light field based on continuous measurements of surface photon irradiance, calculations of losses by surface reflection and measurements of the vertical light attenuation. These measurements have been combined with measurements of the vertical distribution of phytoplankton chlorophyll and the photosynthesis/irradiance curve to produce a measurement of the daily integral of photosynthesis by numerical integration using a PC spreadsheet; the accuracy of the integrations is evaluated. The results have been compared with models that assume a uniform vertical distribution of phytoplankton. Such assumptions produced underestimates of the daily integral of photosynthesis by 50-109% for a population of Aphanizomenon- flos-aquae in the Baltic Sea owing to the overestimate of respiratory losses. Buoyant cyanobacterial populations float up during brief episodes of calm; this increases the insolation they receive and their resultant photosynthetic activity may increase several times. These advantages of buoyancy, provided by gas vesicles, are a major factor in determining the success of waterbloom-forming cyanobacteria. A model is produced of the relationship between the mean depth of the Aphanizomenon phytoplankton population and the daily integral of photosynthesis at different insolations; this may provide the basis for improvement of models applicable to other phytoplankton populations. The integration spreadsheet is available at http://www.bio.bris.ac.uk/research/walsby/integral.htm.

Welch, R., M. M. Remillard, et al. (1988). "Remote sensing and geographic information system techniques for aquatic resource evaluation." Photogrammetric Engineering & Remote Sensing 54(2): 177-185.

Wilhelm, C., J. Bida, et al. (1997). "Interaction between global climate change and the physiological responses of algae." Photosynthetica 33(3-4): 491-503.
The radiation climate as one essential factor influencing phytoplankton primary production will likely change in near future due to the increase of UV-A/B radiation and to stronger vertical mixing. The emission of dimethylsulphide (DMS) from dimethylsulphonium propionate (DMSP) influences the radiation climate due to its impact on cloud formation The diatom Phaeodactylum tricornutum had a high acclimation ability to radiation stress resulting in a rapid recovery from stress induced losses in photosynthetic efficiency. In this case the primary production was not strongly impaired, and UV-B impaired photosynthesis by a mechanism different from that under excess PAR. The DMSP content of Prymnesium parvum was independent of irradiance and nitrogen supply. Total DMSP production of Prymnesium, however, was closely related to the age of the cells which was reduced under high irradiance.

Wilhelm, C., J. Bida, et al. (1996). "The quantitative effect of photoinhibition on the productivity of the diatom Phaeodactylum tricornutum - Implication on the assessment of the primary production under natural conditions." Scientia Marina 60: 249-255.
The effect of photoinhibition on productivity was measured by the use of homocontinuous cultures of the marine diatom Phaeodactylum tricornutum, which were kept at constant chlorophyll content by automatical dilution. The controls were illuminated continuously with 19 mu E m(-2) s(-1), whereas the photoinhibited culture was treated additionally with strong light of 2900 mu E m(-2) s(-1) for a period of 2 and 5 hours per day, respectively. The production was measured on the basis of the dilution volume per time and on the basis of chlorophyll, cell number and dry weight. Photoinhibition was characterised on the basis of changes in variable fluorescence and quantum yield and by light saturation curves measured at different stages during high light treatment and consecutive recovery. Although the strong light treatment reduced, the variable fluorescence to about 20% and the apparent quantum yield for the oxygen evolution was decreased to about 30%, the productivity of photoinhibited cultures was exactly the same as that of the controls. After several inhibition cycles the photoinhibited cultures showed significant increase in oxygen evolution and decreased susceptibility to photoinhibition. However, the results also indicate that photostress modulates the carbon acquisition efficiency under light saturation.

Williams, P. J. L. and D. Lefevre (1996). "Algal C-14 and total carbon metabolisms .1. Models to account for the physiological processes of respiration and recycling." Journal of Plankton Research 18(10): 1941-1959.
A consistent set of equations has been written to describe the net rate of algal (CO2)-C-14 uptake (and where appropriate respiration and photosynthesis) which take into account separately complications due to respiration of the labelled photosynthetic products and the recycling of respiratory CO2. Written specifically into the equations is the concept of 'new' and 'old' carbon, the coefficient q is used in the respiration model to allow for the differential respiration of organic material from the 'new' and 'old' carbon pools. Analytical integrals have been found for respiration and recycling models, and the behaviour of the models studied over periods of 12 h (i.e. up to 70% of the intrinsic generation time). The rate constant for respiration has a greater effect on the behaviour of the recycling than the respiration model. Over short time courses (up to 30% of the intrinsic generation time), the effects of respiration and recycling on net (CO2)-C-14 uptake are quite distinct, especially at high P/R ratios, and not complicated by assumptions over the value of q. Although the value of q will have a time-dependent secondary effect on the modelled total carbon-specific respiration rate, this was found not to give rise to major problems of interpretation. Beyond 50% of the intrinsic generation time, the separate treatment of respiration and recycling in the models becomes less satisfactory. It was concluded that the present equations, which are not constrained by mass balance considerations, would not be appropriate for a model that combines the two processes. The pattern of recycling at low P/R values is identified as one of the major uncertainties in producing models of C-14 uptake. The effect of the release of dissolved organic material can be anticipated in a general way. The models have been used to define an experimental strategy to establish the separate effects of respiration and recycling on the time course of net C-14 uptake. The initial rates give the dearest resolution of the two processes and it would appear that with photosynthetic rates in the region of 1 day(-1),incubation periods up to 3-6 h would be suitable to determine the importance of recycling in controlling net C-14 uptake. With the present models, only in the absence of recycling could the effect of respiration be studied and the value of q established.

Wright, S. W. and S. W. Jeffrey (1987). "Fucoxanthin Pigment Markers of Marine-Phytoplankton Analyzed by Hplc and Hptlc." Marine Ecology-Progress Series 38(3): 259-266.

Wright, S. W., S. W. Jeffrey, et al. (1991). "Improved Hplc Method for the Analysis of Chlorophylls and Carotenoids from Marine-Phytoplankton." Marine Ecology-Progress Series 77(2-3): 183-196.
Using a ternary gradient system, over 50 carotenoids, chlorophylls and their derivatives were separated from marine phytoplankton. Only 2 pairs of carotenoid pigments (19'- butanoyloxyfucoxanthin and siphonaxanthin, and 19'- hexanoyloxyfucoxanthin and 9'-cis-neoxanthin) and 3 chlorophylls (chlorophylls c1, c2 and Mg 2,4 divinyl pheoporphyrin a5 monomethyl ester [Mg2,4D]) were not resolved. Pigment chromatograms are presented for 12 unialgal cultures from 10 algal classes important in the marine environment: Amphidinium carterae Hulbert (Dinophyceae); Chroomonas salina (Wislouch) Butcher (Cryptophyceae); Dunaliella tertiolecta Butcher (Chlorophyceae); Emiliania huxleyi (Lohmann) Hay et Mohler and Pavlova lutheri (Droop) Green (Prymnesiophyceae); Euglena gracilis Klebs (Euglenophyceae); Micromonas pusilla (Butcher) Manton et Parke and Pycnococcus provasolii Guillard (Prasinophyceae); Pelagococcus subviridis Norris (Chrysophyceae); Phaeodactylum tricornutum Bohlin (Bacillariophyceae); Porphyridium cruentum (Bory) Drew et Ross (Rhodophyceae), and Synechococcus sp. (Cyanophyceae). A chromatogram is also given of a complex mixture of over 50 algal pigments such as might be found in a phytoplankton field sample. This method is useful for analysis of phytoplankton pigments in seawater samples and other instances where separations of complex pigment mixtures are required.

Wright, S. W. and J. D. Shearer (1984). "Rapid extraction and HPLC of chlorophylls and carotenoids from marine phytoplankton." J. Chrom. 294: 281-295.

Wright, S. W. and R. L. van den Enden (2000). "Phytoplankton community structure and stocks in the East Antarctic marginal ice zone (BROKE survey, January-March 1996) determined by CHEMTAX analysis of HPLC pigment signatures." Deep-Sea Research Part Ii-Topical Studies in Oceanography 47(12-13): 2363-2400.
The distribution and abundance of phytoplankton communities off east Antarctica were surveyed using CHEMTAX analysis of HPLC pigment profiles, supplemented by microscopy. Eight north-south transects were surveyed between 80 degrees E and 150 degrees E, from approximately 63 degrees S to the sea-ice, during Jan.- Mar. 1996. Spatial resolution of 1-16 km along the shelf break allowed fine-scale resolution of features associated with the ice edge and the Antarctic Slope Front. The maximum concentration of chlorophyll a (Chl a) was 3.4 mu g 1(-1), although most transects had maxima less than or equal to 1.0 mu g 1(-1). Five 'low chlorophyll' transects had average integrated abundances of chi a < 38 mg m(-2), while three 'high chlorophyll' transects had average abundances > 52 mg m(-2). CHEMTAX software was used to estimate the contribution of the different algal classes to total chi a. Eight algal categories were operationally defined by their pigment content: Diatoms, Dinoflagellates, Cryptophytes, Prasinophytes, Chlorophytes, Cyanobacteria, and two categories of haptophytes: Hapto3s (typified by coccolithophorids) and Hapto4s (including Phaeocystis antarctica plus Parmales and other chrysophytes). Regions with melting pack ice typically had an algal bloom that was variable in composition and usually fairly uniform above a deep pycnocline. Significant quantities of detrital matter sank from beneath the melting ice. At each ice edge, there was a local minimum in surface Chi a concentration associated with krill and, in one case, salps. Most algal categories had concentration minima there, but Cryptophytes and often Dinoflagellates and Cyanobacteria had local maxima, perhaps due to selective grazing. North of the ice edge, strong subsurface Chi a maxima were the norm, with concentrations on average 170% of surface values (495% max.) Chlorophyll concentrations were lower in the eastern half of the survey area than the west, although the composition of communities was similar. The composition, concentration and vertical distribution of algal stocks appeared related to the degree of thermal stratification of the mixed layer. Stratified waters had the highest concentrations of Chi a and were associated with high concentrations of Diatoms, whereas well-mixed regions were associated with Hapto4s. Maximum concentrations of most algal groups were principally found on the seasonal pycnocline. However, in stations with well-mixed surface waters, a community dominated by Prasinophytes and Hapto4s was consistently found in the T-min layer whereas other algal groups were found on the pycnocline. Subduction of communities from the T-min layer was apparent at the Antarctic Slope Front. Significant local grazing effects were noted, and it is likely that regional differences in dominant zooplankton may be related to differences in algal stocks. (C) 2000 Elsevier Science Ltd. All rights reserved.

Yamamoto, T. (1993). "Latitudinal differences in temperature adaptation pattern of phytoplankton photosynthetic activity." Proceedings of the NIPR Symposium on Polar Biology(6): 171.

Yamazaki, H. and D. Kamykowski (1991). "The vertical trajectories of motile phytoplankton in a wind-mixed water column." Deep-Sea Research 38(2): 219-241.

Yentsch, C. S. and D. W. Menzel (1963). "A method for the determination of phytoplankton chlorophyll and phaeophytin by fluorescence." Deep Sea Research 10: 221-231.

Yoder, J. A. and S. S. Bishop (1985). "Efects of mixing-induced irradiance fluctuations on photosynthesis of natural assemblages of coastal phytoplankton." Mar. Biol. 90: 87-93.

Zar, J. H. (1999). Biostatistical Analysis. Upper Saddle River, New Jersey, Prentice-Hall, Inc.

Zelt, R. B. (1991). "GIS technology used to manage and analyse hydrologic information." GIS World(August): 70-73.

Zlotnik, I. and Z. Dubinsky (1989). "The effect of light and temperature on DOC excretion by phytoplankton." Limnology and oceanography 34(5): 831.

Zonneveld, C. (1998). "A cell-based model for the chlorophyll a to carbon ratio in phytoplankton." Ecological Modelling 113(1-3): 55-70.

Zonneveld, C. (1998). "Photoinhibition as affected by photoacclimation in phytoplankton: a model approach." Journal of Theoretical Biology 193(1): 115-123.

Zucchi, M. R. and O. Necchi (2001). "Effects of temperature, irradiance and photoperiod on growth and pigment content in some freshwater red algae in culture." Phycological Research 49(2): 103-114(12).