Meiofauna Spatial-Temporal Distribution in a Subtropical Estuary of Southern Coast Brazil

Abstract

The meiofauna spatial-temporal distribution of the Tramandaí-Armazém estuary, RS, Brazil was investigated during two periods: winter 1999 and summer 2000. During the winter, six habitat units were sampled. Two of them situated in theArmazém lagoon (called units 1 and 2), one in an access channel to theAtlantic Ocean (3) and the other three in the Tramandaí lagoon (units 4, 5 and 6). During the summer, besides the aforementioned units, an area of the Armazém lagoon with occurrence of was also considered (called unit R). Nine samples were collected in each habitat unit using a 2.7 cm inner diameter corer. Environmental factors were measured in the field. The meiofauna dominant group was Nematoda, followed by Copepoda and other groups. Densities ranged from 49 ind.10 cm in unit 5 (Tramandaí lagoon) to 3117 ind.10 cm in unit 1 (Armazém). The highest densities, in both summer and winter were registered in the units sampled in the Armazém lagoon. The multidimensional scaling analysis applied to winter meiofauna samples pointed to the formation of three different groups comprising Armazém lagoon, Tramandaí lagoon and access channel samples, respectively. In the summer this separation was not so clear. The results lead to the conclusion that the main factors structuring spatial-temporal distribution of meiofauna in the Tramandaí-Armazém estuary were salinity and sediment granulometric characteristics, with variations induced by the hydrodynamics.