Distribution of benthic foraminifera in the southwestern zone of the estuarine-lagoonal system of Iguapé-Cananéia (Brasil)

Abstract

One hundred species of benthic foraminifera were found in the study area (25ºS - 48ºW). The surface sediment of this lagoon contains from 0 to 3,000 tests per 50 cm³ and up to 32 species. The foraminifera fauna of the lagoonal system of Iguape-Cananéia is the richest among those described in other paralic environments of Brazil. The richness of foraminifera fauna can result from the strong marine influence in the Baía de Trapandé. The foraminifera distribution in the study area is characterized by the occurrence of marine assemblages nearby the mouth, with a gradual increase in agglutinating species, such as,Ammotiwn salsum and Gaudryina exilis. In the confined areas, with low salinity, the assemblages are oligospecific and Milammina earlandi Is dominant. The abundance of Pararotalia in the Mar de Cananéia shows that this environment is less restricted than Mar de Cubatão, where the genus is absent. The distribution of foraminifera species shown to be also influenced by urbain sewages.