Composition, abundance, and diversity of limnetic cladocerans (Crustacea: Anomopoda and Ctenopoda) in a black-water lake in the Negro River basin, Amazonas State, Brazil

Abstract For the past 10 years, studies have contributed greatly to knowledge regarding the composition and distribution of the planktonic cladocerans of Tupé Lake in Amazonas State, Brazil, but comparisons between these studies have not been made, and this would increase the comprehension of the ecology of these organisms and their environment. Periodically the hydrological conditions in Tupé Lake change, due to its connecting channel with the Negro River. The purpose of this study was to determine the composition, abundance and diversity of cladocerans in the limnetic zone of Tupé Lake and compare the results with previous studies performed there. Samples were taken in April, June, September, October, November/08 and February/09 in 4 stations located in different areas of the lake. Ceriodaphnia cornuta G.O. Sars, 1886, Bosminopsis deitersi Richard, 1895 and Bosmina cf. longirostris (O.F. Müller, 1785) were the most abundant and frequent species of cladocerans among the 25 recorded species. Higher abundance and richness were observed during the low water phase (October/08). A relationship between the number of samples taken, as well as the type of sampling gear used, and the species richness was observed, when comparing this and previous studies performed in the lake.