Phytoplankton Group Composition Research Articles

Phytoplankton and pigment composition during an Emiliania huxleyi bloom in the Black Sea

Alterations in composition and carbon biomass of phytoplankton community are closely related to seasonal variations, anthropogenic inputs and ultimately climatic changes in a longer perspective. Accuracy of the collected data is important to determine changes occurring in phytoplankton community composition. An intercomparison exercise of haptophyte abundance obtained by microscopy was performed by three research laboratories based on samples taken from 2 to 11 June 2016, in the western and central Black Sea. Total carbon biomass of phytoplankton groups was estimated by one of the three laboratories based on microscopy. Phytoplankton group composition was also determined with marker pigments. Carbon biomass of large sized diatoms and dinoflagellates was correlated with CHEMTAX derived chlorophyll a concentrations (Chl a) of these groups (r2=0.44-0.60, p<0.05). According to microscopy, carbon biomass of dinoflagellates was generally higher than that of diatoms and haptophytes, while based on HPLC-CHEMTAX analysis haptophytes and diatoms dominated in the region. Abundance of Emiliania huxleyi obtained by three laboratories were significantly different from each other (One way ANOVA) and abundance of only one of the laboratories was correlated with 19’-hexanoyloxyfucoxanthin concentration. Difference in abundance of this nanoplankton species among different laboratories appears to be related to both methodology in counting the cells and fixation of samples.

Marine big data-driven ensemble learning for estimating global phytoplankton group composition over two decades (1997–2020)

Accurate monitoring of the spatial-temporal distribution and variability of phytoplankton group (PG) composition is of vital importance in better understanding of marine ecosystem dynamics and biogeochemical cycles. While existing bio-optical algorithms provide valuable information, relying solely on satellite ocean color data remains insufficient to obtain high-precision retrieval of PG due to the intricate nature of the bio-optical signal and PG composition itself. An interdisciplinary approach combining advancements in machine learning with big data from ocean observations and simulations offers a promising avenue for more accurate quantification of PG composition. In this study, an ensemble learning approach, called the spatial-temporal-ecological ensemble (STEE) model, is developed to construct a robust prediction model for eight distinct phytoplankton groups (i.e., Diatoms, Dinoflagellates, Haptophytes, Pelagophytes, Cryptophytes, Green Algae, Prokaryotes, and Prochlorococcus). The proposed method introduces multiple data simultaneously: ocean color, physical oceanographic, biogeochemical, and spatial and temporal information. An ensemble strategy is applied to increase the performance of the model by merging three advanced machine-learning algorithms. The combined validation of multiple cross-validation (CV) strategies (i.e., standard, spatial block, and temporal block CVs) shows that the proposed STEE model has superior robustness and generalization ability. In addition, the analysis shows a high degree of concordance between the independent datasets and the modeled estimations for long-time series sites, indicating that the STEE model is capable of effectively monitoring long-term trends in phytoplankton group composition. Finally, the proposed model was utilized to retrieve global monthly phytoplankton group products (STEE-PG) over an extended period (September 1997 to May 2020), and comparisons demonstrated better rationality of spatio-temporal distribution than existing satellite-derived phytoplankton group products. Hence, this new model comprehensively integrates all kinds of observation data and yields long-term global PG products with high accuracy, which will enhance our understanding of the response of marine ecosystems to environmental and climate change.

Light absorption spectra of naturally mixed phytoplankton assemblages for retrieval of phytoplankton group composition in coastal oceans

AbstractPhytoplankton group composition is complex and highly variable in coastal waters. Given that different taxonomic groups have different pigment signatures, which in turn impact the light absorption spectra of phytoplankton, the absorption spectral‐based approach has the potential for distinguishing phytoplankton groups. Using a large dataset of in situ surface observations of concurrent HPLC (high‐performance liquid chromatography) pigments and phytoplankton absorption spectra collected from 2015 to 2018 in Chinese coastal oceans, in situ phytoplankton group composition was obtained from chemotaxonomic analysis (CHEMTAX). By using the linear additive principle on phytoplankton absorption spectra and CHEMTAX results, the chlorophyll‐specific absorption spectra of eight phytoplankton groups were reconstructed, including prasinophytes, dinoflagellates, cryptophytes, chlorophytes, cyanobacteria, diatoms, chrysophytes, and prymnesiophytes. These chlorophyll‐specific absorption spectra were subsequently used as inputs to a spectral‐based inversion model for estimating phytoplankton group composition from the phytoplankton absorption coefficient. The optimal band selection and initial guesses of the phytoplankton group composition, derived from correlation and HCA (hierarchical cluster analysis) analyses, were included in the model inversion to improve the accuracy of retrievals. The performance of the proposed model was validated using an independent dataset, showing accurate estimates of chlorophyll a (Chl a) concentrations for seven phytoplankton groups (0.371 ≤ r ≤ 0.721, p &lt; 0.05), apart from chrysophytes. Our results suggest that the absorption spectral‐based approach is able to discriminate phytoplankton group composition quantitatively, which has implications for retrieving Chl a concentrations of phytoplankton groups from hyperspectral platforms and satellites.

Assessment of phytoplankton group composition in the Golden Horn Estuary (Sea of Marmara, Turkey) determined with pigments measured by HPLC-CHEMTAX analyses and microscopy

AbstractPhtytoplankton group composition determined by microscopy was compared with high performance liquid chromatography (HPLC) derived from pigment signatures in surface water samples taken bi-weekly and monthly between October 2018 and September 2019 in the Golden Horn Estuary (Sea of Marmara). A total of 80 eukaryotic phytoplankton taxa belonging to eight algal classes were identified in surface water during the study period. Forty-three taxa (54%) were diatoms, 29 taxa (36%) were dinoflagellates and eight taxa (10%) were other phytoflagellates. The average contribution of diatoms to total phytoplankton abundance decreased considerably (41 to 25%), while the average contribution of dinoflagellates and other phytoflagellates increased markedly (59 to 75%) from the lower to the middle estuary. Chlorophyll-a and seven other group-specific pigments, including fucoxanthin, peridinin, chlorophyll-c1 + c2, alloxanthin, 19′-hexanoyloxyfucoxanthin, 19′-butanoyloxyfucoxanthin and divinyl chlorophyll-a were identified in the study area. The relative contribution of the major phytoplankton groups to chlorophyll-a was estimated on three different initial ratio matrices by CHEMTAX. The results obtained were compared with those from microscopic examination. It was concluded that the CHEMTAX method was not accurate enough to characterize the phytoplankton community in the Golden Horn Estuary ecosystem and microscopic analysis was essential to determine the major contributing species to chlorophyll-a.

Changes in phytoplankton composition of the Golden Horn Estuary (Sea of Marmara) following remediation

AbstractChanges in phytoplankton composition of the Golden Horn Estuary were investigated following remediation, through seawater transfer from the Strait of Istanbul to the estuary. Average values of Secchi depth, salinity and dissolved oxygen increased during this study when compared with a previous study. The average number of species (S) and species diversity (H′) increased and they correlated positively with Secchi depth, salinity and dissolved oxygen. There was a similar phytoplankton group composition between this and a previous study, however, the species composition differed. A total of 127 taxa consisting of diatoms (66 taxa), dinoflagellates (49 taxa) and others (12 taxa) were identified. Abundance of dinoflagellates and phytoflagellates and their relative contribution to the total phytoplankton abundance increased during this study, however, the abundance of diatoms and their relative contribution decreased notably, as compared with the previous study. There was a significant positive correlation between salinity and dinoflagellates and phytoflagellates (P&lt; 0.01), and also between Secchi depth and dinoflagellates (P&lt; 0.01) in the upper estuary. Additionally, salinity and Secchi depth correlated positively with species diversity (H′) and number of species (S) (P&lt; 0.01). The increase in water transparency probably contributed to the increase in abundance of dinoflagellates and phytoflagellates. The results revealed that water transparency was one of the most important factors affecting phytoplankton composition in the study area. Changes in some environmental conditions following seawater transfer appear to have changed phytoplankton composition. As a result, phytoplankton species were confirmed as a very good indicator of changed environmental conditions.

Coastal Phytoplankton Pigments Composition in Three Tropical Estuaries of Indonesia

In this study, the composition and distribution of phytoplankton pigments and its relation to nutrients and light was investigated, and an elaboration of using it as a proxy for phytoplankton group composition followed, in different nutrient-level tropical bays of Indonesia. Phytoplankton pigment analysis by using High Performance Liquid Chromatographer (HPLC) resulted in a set of pigments of chlorophyll-a (Chl-a), chlorophyll-b (Chl-b), chlorophyll-c (Chl-c), lutein, zeaxanthin, fucoxanthin, peridinin, diadinoxanthin, and ß-carotene. Linear multi regression and multivariate principal component analysis (PCA) showed that algae pigments correlate positively with nutrients and are not significantly correlated with underwater light and water transparency, suggesting important roles of nutrients for phytoplankton development in tropical estuaries. There were differences in total algae pigment concentration between bays (p &lt; 0.005), showing that the eutrophic system of Jakarta Bay was the highest (mean of 10.55 μg L−1), Lampung Bay was the second highest (mean of 3.37 μg L−1), and the lowest were the oligotrophic waters of Semangka Bay (mean of 0.80 μg L−1). At all bays studied, high nutrient sites, which were located in the river mouths and inner part of the bay, were always characterized by high phytoplankton pigment concentration. Pigment composition had a high correlation with phytoplankton composition: diatoms with fucoxanthin, dinoflagellates with peridinin and Chl-c, and Chlorophyceae with Chl-b and lutein. This conformity suggests that algae pigments can be used as a biomarker for phytoplankton group determination along with microscopic species identification.

Report on the Diatoms and Dinoflagellates Distribution along the Algerian Coasts: Inter-Region Comparison

The phytoplankton group's composition is an excellent indicator of the state of coastal waters. The aim of this study is to explore spatial variability of phytoplankton in shallow coastal areas from different regions (East, Center and West) of the Algerian coast. The quantitative and qualitative study of the phytoplankton population was conducted on samples taken during the 2012–2013 period by the research vessel GRINE BELKACEM. The qualitative results show a significant diversity of diatoms and dinoflagellates, which rank first and second in the total flora (Fr > 50%). This finding is also confirmed quantitatively by the abundance values in both 2013 and 2012 samples which largely exceeds the average value in most other areas of the western region (56%) and slightly exceeding 52% in all central areas which represent an equi-distribution between diatoms and dinoflagellates. The Dinoflagellates contribute significantly to the quantitative richness in the eastern region (>60%). The minimum value of Dia/Dino index, recorded in the eastern region confirms the dominance of the dinoflagellates especially in Skikda (0.31) (Skikda).However, our results reveal the presence, in smaller proportion, of other groups such as the cocolithophoridae and euglenophyceae.

Evaluation of FluoroProbe® performance for the phytoplankton-based assessment of the ecological status of Mediterranean coastal lagoons.

The European Water Framework Directive and several other legislations worldwide have selected phytoplankton for monitoring the ecological status of surface waters. This assessment is a complicated task in coastal lagoons due to their intrinsic variability, prompting moves to use real-time measurements. Here, we tested the ability of the submersible spectrofluorometer FluoroProbe® to accurately estimate the phytoplankton biomass and to efficiently discriminate spectral groups in Mediterranean coastal lagoons, by using sub-surface water samples (n = 107) collected at Biguglia lagoon (Corsica) in different environmental situations (salinity and trophic state) from March 2012 to December 2014. We compared the estimates of biomass and phytoplankton group composition obtained with the FluoroProbe® (in situ and lab measurements) with the spectrofluorimetrically measured biomass and HPLC-derived quantifications of pigment concentrations. FluoroProbe® provided good estimates of the total phytoplankton biomass (particularly, the lab measurements). The FluoroProbe® data were significantly correlated with the HPLC results, except for the in situ measurements of very weak concentrations of blue-green and red algae. Our findings indicate that factory-calibrated FluoroProbe® is an efficient and easy-to-use real-time phytoplankton monitoring tool in coastal lagoons, especially as an early warning system for the detection of potentially harmful algal blooms. Practical instructions dedicated to non-specialist field operators are provided. A simple and efficient method for discarding in situ measurement outliers is also proposed.

Comparing microscopic counts and pigment analyses in 46 phytoplankton communities from lakes of different trophic state

Summary Comparison between algal pigment analyses using HPLC and subsequent CHEMTAX analysis with microscopic counts from different lakes ranging from ultra‐oligotrophic to eutrophic allowed testing of pigment:chlorophyll a ratios for lakes of different trophic conditions. Microscopic counts and pigment analyses were positively correlated for all groups except for the chrysophytes. When examining the oligotrophic lakes only, microscopic analyses and pigment analyses of chrysophytes were positively correlated, which showed that the oligotrophic pigment ratios were well suited for determining the abundance of the chrysophytes in oligotrophic lakes. In the eutrophic lakes, where chrysophytes constituted less than 10% of the biomass, the weak correlation was most likely related to counting inaccuracies. Chrysophytes, generally indicative of oligotrophic conditions, were three times more abundant in the oligotrophic lakes. They constituted 28% of the total phytoplankton biomass as chlorophyll a measured by the pigment method and 26% of the total phytoplankton biomass measured as biovolume by microscopy. In mesotrophic/eutrophic lakes, chrysophytes constituted only 9% (pigment method) and 8% (microscopy). Similarity analyses comparing the results of these two methods on functional group level documented the high accuracy of the pigment method in detecting all the functional groups present. The results of the pigment analyses showed a more even composition of phytoplankton groups than found by microscopy, where often one or two of the less abundant groups were absent or only sporadically present. The Shannon's diversity index, H’, for functional groups determined from results of the pigment method were higher than the H’ values based on microscopic counts, confirming a more continuous composition of the phytoplankton groups when detected by the pigment method. The pigment method was found to be a useful alternative, which supplemented microscopic counts.

Changes in the Composition and Abundance of Phytoplankton in a Coastal Lagoon of Baja California, M&amp;#233;xico, during 2011

A time series with weekly sampling was conducted from February 20, to December 16, 2011 at a station in the interior of the San Quintin Bay to estimate seasonal changes in the composition and abundance of phytoplankton. Water temperature was recorded and the upwelling index was calculated for the period. Phytoplankton abundance was estimated and phytoplankton were identified by using an inverted microscope and the CHEMTAX program. There were 16 positive phytoplankton anomalies during the year, but only three were considered to be blooms. The blooms were dominated by diatoms and were recorded in the winter, spring and summer. Different genera composed 80% of the total phytoplankton abundance of each of the blooms. The first bloom consisted of diatoms of the genera Pseudo-nitzschia sp. (15.7%), Skeletonema sp. (14.6%), Eucampia sp. (7%), and Navicula sp. (7%); a haptophyte of the genus Imantonia sp. (13.1%); and dinoflagellates of the genus Prorocentrum sp. (4.6%). The second bloom consisted mainly of diatoms of the genera Guinardia sp. (30.6%), Pseudo-nitzschia sp. (21.5%), Skeletonema sp. (14.5%), Chaetoceros sp. (8.4%) and Eucampia sp. (5.3%). The third bloom consisted of Chaetoceros sp. (46.3%), Pseudo-nitzschia sp. (22.6%), Skeletonema sp. (7.29%), and Imantonia sp. (6%). Dinoflagellates were observed in the winter, summer and autumn, but they contributed less biomass than diatoms. Prorocentrum sp., Gymnodinium sp., and Ceratium sp. were among the dinoflagellates that were observed. The differences in abundance and composition of phytoplankton groups in the blooms in San Quintin Bay during 2011 were due primarily to seasonal changes in the physical and chemical factors of the seawater and to upwelling events.

The seasonal variation of the phytoplankton size class in northern South China Sea

Phytoplankton size class variation is a good indicator of water dynamics changes, alga blooms or ecosystem change, for it usually corresponds to different phytoplankton group composition. Remote sensing technique is a very effective method for studying phytoplankton at large scale by virtue of synoptic view and large area cover. Here we detected seasonal and annual phytoplankton size class variation using remote sensing data based on a bio-optical algorithm in northern South China Sea. Result showed that the phytoplankton size class turned to be smaller during summer time, because of the stability of the water body and lack of nutrients. While in winter, the north-east monsoon made the water dynamics become complex. Upwellings, mesoscale eddy, typhoon and a series of drifts bring underwater nutrients up to the sea surface. As a result, phytoplankton with bigger cell size began to grow and the cell size turned to be bigger. The fraction of micro-phytolankton changed from 7% to 10%, while nano-and pico-phytolankton fraction decreased from 29% to 24% and 64% to 62% respectively. Annual change of phytoplankton size classes was in a relatively slow pace, and no big difference was noticed in the normal year. Usually about 1–5 percent change for each size class. When compared 2008 with 1998, a decade variances could be monitored. All the results in this study showed that phytoplankton size class can be an effective indicator of the ecosystem or environmental change.

Spatial and temporal variability of the dimethylsulfide to chlorophyll ratio in the surface ocean: an assessment based on phytoplankton group dominance determined from space

Abstract. Dimethylsulfoniopropionate (DMSP) is produced in surface seawater by phytoplankton. Phytoplankton culture experiments have shown that nanoeucaryotes (NANO) display much higher mean DMSP-to-Carbon or DMSP-to-Chlorophyll (Chl) ratios than Prochlorococcus (PRO), Synechococcus (SYN) or diatoms (DIAT). Moreover, the DMSP-lyase activity of algae which cleaves DMSP into dimethylsulfide (DMS) is even more group specific than DMSP itself. Ship-based observations have shown at limited spatial scales, that sea surface DMS-to-Chl ratios (DMS:Chl) are dependent on the composition of phytoplankton groups. Here we use satellite remote sensing of Chl (from SeaWiFS) and of Phytoplankton Group Dominance (PGD from PHYSAT) with ship-based sea surface DMS concentrations (8 cruises in total) to assess this dependence on an unprecedented spatial scale. PHYSAT provides PGD (either NANO, PRO, SYN, DIAT, Phaeocystis (PHAEO) or coccolithophores (COC)) in each satellite pixel (1/4° horizontal resolution). While there are identification errors in the PHYSAT method, it is important to note that these errors are lowest for NANO PGD which we typify by high DMSP:Chl. In summer, in the Indian sector of the Southern Ocean, we find that mean DMS:Chl associated with NANO + PHAEO and PRO + SYN + DIAT are 13.6±8.4 mmol g−1 (n=34) and 7.3±4.8 mmol g−1 (n=24), respectively. That is a statistically significant difference (P&lt;0.001) that is consistent with NANO and PHAEO being relatively high DMSP producers. However, in the western North Atlantic between 40° N and 60° N, we find no significant difference between the same PGD. This is most likely because coccolithophores account for the non-dominant part of the summer phytoplankton assemblages. Meridional distributions at 22° W in the Atlantic, and 95° W and 110° W in the Pacific, both show a marked drop in DMS:Chl near the equator, down to few mmol g−1, yet the basins exhibit different PGD (NANO in the Atlantic, PRO and SYN in the Pacific). In tropical and subtropical Atlantic and Pacific waters away from the equatorial and coastal upwelling, mean DMS:Chl associated with high and low DMSP producers are statistically significantly different, but the difference is opposite of that expected from culture experiments. Hence, in a majority of cases PGD is not of primary importance in controlling DMS:Chl variations. We therefore conclude that water-leaving radiance spectra obtained simultaneously from ocean color sensor measurements of Chl concentrations and dominant phytoplankton groups can not be used to predict global fields of DMS.

Variability in pigment composition and optical characteristics of phytoplankton in the Labrador Sea and the Central North Atlantic

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 260:1-18 (2003) - doi:10.3354/meps260001 Variability in pigment composition and optical characteristics of phytoplankton in the Labrador Sea and the Central North Atlantic Vivian A. Lutz1,3,*, Shubha Sathyendranath1,2, Erica J. H. Head2, William K. W. Li2 1Department of Oceanography, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada 2Bedford Institute of Oceanography, Box 1006, Dartmouth, Nova Scotia B2Y 4A2, Canada 3Present address: INIDEP, Paseo Victoria Ocampo No. 1, 7600 Mar del Plata, Argentina *Email: vlutz@inidep.edu.ar ABSTRACT: The relationships between photoadaptation, photoacclimation, cell size and the optical characteristics of the phytoplankton community were studied in 2 areas of the Atlantic Ocean. Pigment composition, absorption and fluorescence excitation spectra were analyzed for samples collected during 2 spring cruises: one in the Labrador Sea and the other in the Central North Atlantic. Photoadaptation (i.e. evolutionary adaptation of different species leading to acquisition of different pigment composition) was evident in the distribution of the main phytoplankton pigments in the area. Photoacclimation (i.e. temporary changes in pigment concentrations in a given species) was also noticeable in the changes in pigment composition and optical characteristics of phytoplankton with changes in depth. Size fractionation of samples from the depth of the chlorophyll a (chl a) maximum showed that, on average, chl a concentration and the values of absorption and fluorescence were dominated by the >2 µm fraction of phytoplankton. Spectral variations in absorption and fluorescence excitation were, however, similar for the small and for the large size fractions. A distinct regional distribution of algal groups was observed, in which prokaryotic picophytoplankton (size class <2 µm) dominated in oligotrophic subtropical regions and larger cells (size class >2 µm) dominated in coastal areas and at higher latitudes. Some significant relationships were observed between the relative abundances of pigments characteristic of certain algal groups and optical properties of the sample. For example, the ratio of absorption at 440 nm to that at 676 nm was positively correlated with the ratio of zeaxanthin to chl a, indicating high abundance of picophytoplankton, especially the cyanobacteria Synechococcus and Prochlorococcus. The ratio of absorption at 555 nm to that at 623 nm was positively correlated with the abundance of phycoerythrin-containing Synechococcus. These results show that useful information about phytoplankton group composition and photoacclimation state can be retrieved from optical properties at a regional scale. KEY WORDS: Phytoplankton pigments · Absorption · Fluorescence excitation · Photoadaptation · Photoacclimation · Size fractionation Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 260. Online publication date: September 30, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.

Coastal plankton responses to turbulent mixing in experimental ecosystems

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 171:23-41 (1998) - doi:10.3354/meps171023 Coastal plankton responses to turbulent mixing in experimental ecosystems John E. Petersen*, Lawrence P. Sanford, W. Michael Kemp Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, Maryland 21613, USA *E-mail: petersen@hpl.umces.edu ABSTRACT: Turbulent mixing is increasingly implicated as a key factor regulating ecological dynamics in coastal planktonic systems. Although photosynthesis is directly fueled by light energy, it has been hypothesized that the 'auxiliary' energy provided by mixing can subsidize or control ecosystem function. Unrealistic mixing has also been cited as one explanation for difficulties in reproducing natural plankton dynamics in enclosed experimental ecosystems (mesocosms). To explore the importance of mixing in shallow planktonic ecosystems, we traced changes over a 4 wk period in population, community, and ecosystem level properties in replicate 1 m3 experimental ecosystems subjected to different mixing regimes. Mixing energy was delivered by slowly rotating impellers on a cycle of 4 h on and 2 h off to match the semidiurnal pattern of tidal mixing that characterizes many temperate estuaries. Three mixing levels were generated by altering impeller rotation rates. The intermediate level was scaled to match typical mixing intensities of waters in Chesapeake Bay, the low mixing level approximated calm oceanic surface waters, and the high mixing level approximated the environment within a tidal front. High and low mixing levels encompassed a 6x range in turbulence intensity, a 9x range in the surface-bottom mixing time and eddy diffusivity coefficients, and a 230x range in turbulent energy dissipation rates. Mixing had a significant negative effect on copepod and gelatinous zooplankton abundance and also altered the timing of peak copepod densities. Chlorophyll a dynamics and phytoplankton group composition, as assessed with accessory pigment concentrations, also exhibited modest differences among mixing treatments. Mixing had negligible effects on nutrient concentrations and on community and whole-system productivity and respiration. Important caveats in interpreting the results of this experiment are that system size excluded observation of the effects of large-scale mixing processes, trophic complexity was limited (e.g. no fish), and in this whole-ecosystem context it was difficult to distinguish direct from indirect effects of mixing. Nevertheless, our results imply that ecosystem-level processes in planktonic systems may often be less sensitive to differences in small-scale turbulence than population and community dynamics, and also that mixing effects may be strongly dependent on the specific structure of particular ecosystems. KEY WORDS: Mixing · Turbulence · Plankton · Copepod · Mesocosm · Production · Respiration · Auxiliary energy Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 171. Publication date: October 01, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research.