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(59-10) Ecological structures of zoo- and phytoplankton in aquatic microcosms treated with endocrine disruptors. Hense, Burkhard*,1, Welzl, Gerhard1, Severin, Gabriele2, Jaser, Wolfgang2, Schramm, Karl-Werner2, 1 GSF - National Research Center for Environment and Health, Neuherberg, Germany2 GSF - National Research Center for Environment and Health, Neuherberg, Germany ABSTRACT- Microcosm studies which regard the effects on various communities, such as phyto- and zooplankton, benthos or bacteria, usually present mainly independent results for each of these trophic levels without considering ecological interactions. We conducted several aquatic microcosm studies to investigate the effects of different endocrine disruptors (e.g. nonylphenol, 17 Key words: ecological structure, endocrine, zooplankton, phytoplankton |
-ethinylestradiol) on biocenosis. The testing of endocrine disruptors is based upon the hypothesis that they possibly affect the biocenosis by interfering with the hormone system. The tested chemicals interfere with the hormonal systems of animals. This means, any endocrine activity should primarily disturb the fauna. Found reactions of flora or bacteria should be either indirect, i.e. a result of shifts within the fauna, or caused by other toxic properties of the test substance. For an understanding of the mode of action of toxic chemicals in complex ecosystems it is desirable to get information about possible connections of changes in the different communities. Therefore, phyto- and zooplankton data on taxa level from the microcosm experiments were classified and aggregated according to ecological characteristics, e.g. regarding trophic strategies of zooplankton and edibility of the phytoplankton. The ecological structure was analysed by different statistical methods, e.g. path analysis, redundancy analysis and partial least squares regression, with particular interest to shifts due to the tested substance. Special focus was put on potential time lag of the correlation as it may be an indicator for indirect and direct mode of chemical action.