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Evaluation of toxicity of tannery effluent on plankton community structure: A multispecies microcosm study II

Laboratory experiments were conducted to evaluate the dose-dependent response of tannery effluents on plankton community structure using polyurethane foam (PF) as artificial substrate. Naturally derived planktonic communities on PF provided colonists for the development of new communities under stress conditions in the laboratory. | Turk J Biol 28 (2004) 55-63 © TÜB‹TAK Evaluation of Toxicity of Tannery Effluent on Plankton Community Structure: A Multispecies Microcosm Study II Yalavarthi Naga KOTESWARI Biotechnology and Toxicology Lab., Environment Protection Training and Research Institute (EPTRI), Hyderabad – 500 032, India Ravichandran RAMANIBAI Unit of Biomonitoring and Management, Department of Zoology, University of Madras, Guindy Campus, Chennai - 600 005, India Received: 17.06.2004 Abstract: Laboratory experiments were conducted to evaluate the dose-dependent response of tannery effluents on plankton community structure using polyurethane foam (PF) as artificial substrate. Naturally derived planktonic communities on PF provided colonists for the development of new communities under stress conditions in the laboratory. Predictions of colonization rate, taxonomic richness and relative abundance in a series of microcosms dosed with a gradient of tannery effluent from 20% to 35% concentration were assessed after the initial dosage study (1% to 15%). Changes in taxonomic composition occur at high levels of stress. End points responding at increasing levels of stress are declines in species numbers relative to expected numbers followed by an increase in nutrient concentration from control to tannery effluent treated microcosms. Key Words: Multispecies, plankton community structure, tannery effluent, taxonomic richness Introduction Many questions about the response of complex systems to toxicity are difficult to address by describing different natural environments (1). In order to explain the relationships between changes in communities and chemical stress, experiments with similar artificial ecosystems have been useful. Single species toxicity tests have served as efficient ranking tools to monitor the effect of existing discharges on aquatic organisms (2). But multispecies microcosm toxicity tests permit the determination of the effects of direct toxicant discharge on characteristics