Biogeographyc Meiofauna Regions from Patagonian Coast, Argentina

CATALINA T. PASTOR; VIRGINIA LO RUSSO

Bahía Blanca, Buenos Aires

Simposio; ECSA 44 Science and Management of Estuaries and Coasts. A Tale of Two Hemispheries; 2008

Estuarine and Coastal Science Association

The aim of this study was to identify marine coastal meiofauna at Patagonia (Argentina)and to describe their latitudinal changes along the coast. Seven locations distributed in three different latitudes were sampled at Río Negro (40º 43'S) and Chubut provinces (42º 45'S and 45º 59'S). The collection methodology was the same for all seven sites. In each site fifteen samples were collected, five for each chosen littoral fringe (upper, mid and lower). A Plexiglas corer (2.9 cm inner diameter) was used. Then, samples were fixed in formalin 5% and carried to the lab. The separation was done with elutriation/decantation/Ludox method. The meiofauna organisms found were observed and quantified under a stereoscopic microscope. As results we found that Nematoda and Copepoda were the dominant taxa at paralel 40º S, meanwhile Nematoda and Turbellaria dominated from the paralel 42º S to South. San Antonio Oeste Beach (Río Negro Province) showed the highest differences at the community structure level with the rest of the samples. So meiofauna was distributed in two biogeographyc coastal regions separated by the parallel 42º S of latitude. This area appears to be an ecotonal zone.