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The concept of phytoplankton functional groups was used to assess phytoplankton community structure in an attempt to better understand their spatial and seasonal variation in Lake Okeechobee, USA. Samples were collected for analyses during summer and winter. 23 phytoplankton functional groups were identified among 102 species, of which 9 groups (H1, M, C, MP, Y, S1, J, X1 and X2) were categorized as dominant. Y represented by Cryptomonas ovate and H1, represented by Anabaena circinalis and Anabaena variabilis, were dominant in some sites in summer corresponding to higher temperatures. In winter, the biomass of the functional groups was dominated by chlorophyta group X2 corresponding to lower temperatures, and relatively high nutrients. Redundancy analysis (RDA) with Monte Carlo test revealed that water temperature (WT), TP, and TN were the most dominant environmental variables which influenced phytoplankton functional group distribution in Lake Okeechobee. Functional group H1 was associated with TN, pH, TP and WT. Similarly, functional group Y was significantly positively correlated with TN, TP and WT but negatively correlated with TN/TP ratios. This study reveals the importance of physical–chemical variables across a spatial and seasonal gradient, in structuring phytoplankton functional groups, and consequently in the assessment of environmental status of the lake.

In this study, the concept of phytoplankton functional groups was used to assess phytoplankton community structure in an attempt to better understand their spatial and seasonal variation in extremely alkaline Dali Nur Lake. Samples were collected for analysis during spring, summer and autumn for a period of two years. We identified 13 phytoplankton functional groups (Lo, S1, H1, P, C, MP, X3, Y, X2, W1, J, F, and T) among 37 species out of which 7 groups Lo, H1, P, C, MP, X2, and F were dominant. The biomass of phytoplankton functional groups in the Lake exhibited a strong seasonal variation with the highest biomass value observed in autumn and lowest in spring. Functional groups MP, P, and C were dominant in spring when the temperatures were very low. Groups H1 and X2 were the dominant in summer corresponding to higher temperatures. In autumn groups Lo and X2 were the dominant corresponding to high levels of total phosphorus (TP). Our study revealed that alkalinity, pH, arsenic, chemical oxygen demand, and TP are the most important physical–chemical variables structuring the phytoplankton functional groups in Dali Nur Lake. Functional groups Lo and X2 were mainly influenced by TP while groups MP and P flourished better under high conditions of arsenic. This study reveals the importance of physical–chemical variables in the spatial and seasonal gradient, in structuring phytoplankton functional groups, and consequently in the assessment of environmental status of the lake.

In this study, the concept of functional traits was used to classify zooplankton into functional groups and their seasonal dynamics were determined in relation to physico-chemical factors in a highly turbid and nutrient-rich wetland. This study revealed a seasonal variation of both physico-chemical factors and biomass of zooplankton functional groups. Water temperature (TEP), total phosphorus (TP), ferrous ion (Fe2+) and total carbon (TC) were significantly higher in summer while water transparency (SD) was notably higher in spring. Zooplankton functional group biomass was higher in summer (5.11 mg/L) followed by winter, autumn and spring (0.91, 0.72 and 0.28 mg/L, respectively). Large copepods and cladoceran carnivore (LCC) was the dominant functional group in spring accounting for about 86.7% of the total biomass. In summer, MCF (Middle copepods and cladocerans filter feeders) was the dominant group probably because of the optimal temperature and availability of nutrients. Pearson correlation and RDA analysis results suggested that Fe2+, TP and TEP were the major factors influencing zooplankton functional groups. Notably, turbidity was not the main factor despite the fact that Small Xingkai Wetland Lake is a very turbid lake. The variation of zooplankton functional groups among seasons highlights the role of physico-chemical factors in structuring zooplankton composition.

In spring, summer, autumn 2015, we studied the seasonal variation of phytoplankton community structure in six rivers within Duobukuer Nature Reserve, and made preliminary evaluation of the water quality in Duobukuer Nature Reserve based on phytoplankton diversity. The results showed that a total of 7 phyla, 41 genera, 66 species and varieties of phytoplankton were identified in Duobukuer Nature Reserve; the annual species composition was dominated by diatom (59%) which also preponderated in dominant species (84. 3%), biomass (68%) and abundance (75%), with no significant seasonal variation. Shannon-Wiener diversity index (H') and Pielou evenness index (J) were used to evaluate the water quality in 13 sampling points, and the results showed that the water quality was good in Duobukuer Nature Reserve, the sampling points 5, 6 and 12 presented β-pollution, and other sampling points were in an oligosaprobic-clean state. [ABSTRACT FROM AUTHOR]