Contribuição ao estudo das Diatomáceas das águas de abastecimento público de Florianópolis

Abstract

The town of Florianópolis is supplied by the dam of Pilões, situated on the Continent, in the municipality of Santo Amaro da lmperatriz, on an altitude of 236 m (barrage.level). We tried to contribute to the sanitary examination of the water which is destined to the supplying of the capital of the State of Santa Catarina, realizing researches about the Diatomaceas which occur in the referred dam. There were determined 55 species with predominance of oligohalobic, cosmopolitan, oligosaprobic, oligotrophic species. Among the oligosaprobic we found: Gomphonema gracile Ehr.; Conphonema parvulum Kutz. Grun.; Hantzschia amphioxys (Ehr.) Grun.; Pinnularia borealis Ehr.; Pinnularia microstauron (Ehr.) Cl.; typical of slightly contaminated water. These conclusions were confirmed afterwards, by the chemical examination of the water, which proved a low contamination tax (percentage).