Levantamento da biodiversidade de amebas testáceas em sedimentos de lagoas artificiais de São Leopoldo, Rio Grande do Sul, Brasil Biodiversity survey of testaceous amoebae in artificial lagoon sediment at São Leopoldo, Rio Grande do Sul, Brazil

As a contribution to the knowledge of testaceous amoebae, the aim of this study was to develop a seasonal survey on the abundance and richness of the live fauna of these protozoa inhabiting three artificial lagoons located on the campus of the Universidade do Vale do Rio do Sinos. In each season of the year, two superficial sediment samples were collected from each lagoon (C2, C5 and C7). The samples were then immediately conserved by the addition of a 10% formaldehyde solution. The pH, temperature and density of the water table were checked at each point. In the laboratory, 10cm3 of each sample were washed, using sieves with a mesh of 0.045mm, dyed, dried in an oven and sprinkled in a carbon tetrachloride solution. The floating material was deposited in mini Petri dishes and analyzed under a stereoscopic microscope. From the C2 lagoon, in summer the dominant species were Centropyxis constricta f. aerophila and Difflugia urceolata; in autumn, the dominant species were Centropyxis constricta and Difflugia corona; in winter, the dominant species were Lesquereusia modesta and Difflugia corona, and in spring, the dominant species was Centropyxis marsupiformis. From the C5 lagoon, the dominant species was Difflugia pyriformis, except in summer when the dominant species was Cucurbitella mespiliformis var. africana. From the C7 lagoon, Difflugia acuminata var. inflata dominated in the assemblages, but in winter the dominant species was Difflugia pyriformis.