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Abstract

The composition, seasonal sucession of Cladocera and food availability as chlorophyll-a or as sestonic carbon (particles less than 20 pm) were studied weekly from February to April at Lago Jacaretinga (Brazil). The Cladocera community, shifted from a complete dominance by Diaphanosoma sarsi, Ceriodaphnia cornuta, and Daphnia gessneri corresponding with the time of low water level to dominance and density by, Moina reticulata with the time of high water level period. The values of edible chlorophyll-a, particulate organic carbon (POC), and the carbon levels of the edible non-algal fraction showed a gradual increase with the entry of the water from the Solimões River to the lake. The edible algal carbon did not vary markedly. It is evident that the non-algal contribution to the sestonic carbon content was greater than algal carbon by about ten times, indicating that non-algal particulate carbon accounts for the large amount of total POC. Nevertheless, there is not a condition of food limitation in the lake because the algal carbon always attained above 0.1 mg C/l.