title: Impact of 17alpha-ethinylestradiol on the plankton in freshwater microcosms--II: responses of phytoplankton and the interrelation within the ecosystem.
abstract: Effects of 17alpha-ethinylestradiol (EE) on phytoplankton were investigated in a lentic freshwater microcosm study. Treatment with EE caused a shift in the species composition as shown by a principle response curve. Whereas densities of Cyanophyceae, Dinophyceae, and Chrysophyceae increased, those of Conjugatophyceae and Cryptophyceae decreased. Furthermore, relative density of Chlorophyceae declined after EE treatment. The changes showed taxa-specific time dependencies. Some species, especially the cyanobacterium Cyanobium parvum, bloomed after the treatment. EE treatment promoted total abundance and biomass of phytoplankton. Although the number of species per microcosm increased, the diversity indices (Shannon-Wiener, Simpson) tended to lower values. The ecosystem only partly recovered during the investigated post-treatment period of 6 weeks. Probably at least the main effects were caused indirectly, i.e. via decrease of grazing zooplankton (crustaceans). The relation of EE to variation of phytoplankton composition was closer than those of other abiotic factors, indicating the relevance of its impact. EE also probably affected nutrients of the phytoplankton.
authors: GSF-National Research Center for Environment and Health, Institute of Biomathematics and Biometry, Neuherberg, Germany. burkhard.hense@gsf.de
authors: Burkhard A
authors: BA
authors: Hense
authors: Wolfgang
authors: W
authors: Jaser
authors: Gerhard
authors: G
authors: Welzl
authors: Gerd
authors: G
authors: Pfister
authors: Gabriele F
authors: GF
authors: Wöhler-Moorhoff
authors: Karl-Werner
authors: KW
authors: Schramm
mesh_terms: D044822:Biodiversity; D004997:Ethinyl Estradiol / Q000494:pharmacology*; D005618:Fresh Water / Q000382:microbiology; D007700:Kinetics; D010839:Phytoplankton / Q000145:classification / Q000187:drug effects* / Q000254:growth & development; D011156:Population Density; D013045:Species Specificity
chemical_list: D004997:Ethinyl Estradiol