Zooplankton and water quality of lakes of the Northern Coast of Rio Grande do Sul State, Brazil
PEDROZO 1, C. DA S. & ROCHA2, O.
1 Departamento de Ecologia, Universidade Federal do Rio Grande do Sul: Av. Bento Gonçalves, 9500, prédio 43422, CEP 91540-000, Porto Alegre, RS, Brazil.
2 Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Carlos: Via Washington Luiz km 235, C. P. 676, CEP 13560-905, São Carlos, SP, Brazil.
ABSTRACT: The indicator properties of zooplankton assemblages were evaluated along the environmental gradient of water quality caused by organic effluent discharge in the following lakes: Marcelino, Peixoto, Pinguela, Palmital, Malvas and Passo, located on the coastal plain of Rio Grande do Sul and connected by channels. The abundance of zooplankton species was interpreted by cluster analysis revealing a relationship to the limnological characteristics of the ecosystem. The data analyses of relative abundance were used to identify “sensitive”, “indifferent”, and “tolerant” species with the aim of selecting bioindicators of organic pollution. Brachionus caudatus, B. angularis, B. calyciflorus, Keratella cochlearis tecta, Euchlanis dilatata, Filinia longiseta, Bosmina longirostris, Moina micrura and Acanthocyclops vernalis were considered “tolerant” to organic pollution. K. cochlearis, K. americana, K. tropica, K. valga, Trichocerca capuccina, Pompholyx complanata, Ceriodaphnia cornuta cornuta, C. cornuta rigaudi, Diaphanosoma birgei and Notodiaptomus incompositus were considered “indifferent”, while Bosminopsis deitersi, Moina minuta and Thermocyclops minutus were considered “sensitive” to organic pollution.
Key-words: Zooplanktonic community, lakes, environmental variables, bioindicators, environmental quality.