Diatoms from the biofilm at the sediment-water interface in the mangroves of Sepetiba Bay, Rio de Janeiro State, Brazil

Abstract

This study describes the diatom flora from the biofilm of the sediment-water interface at the mangroves of Coroa Grande, Sepetiba Bay, Rio de Janeiro State, Brazil The microalgal community is constituted by Auliscus coelatus Bail, Actinopthycus undulatus, Biddulphia sp., Cocconeis scutellum, Cyclotella Stylorum Bright, Fragilaria sp., Melosira nummuloides, Navicula lanceolata, Thalassionema sp. and Thalassiosira sp.. The biofilm is associated to clay sediments on the surface of the mangrove soil. The interaction between these microalgae and the mangrove environment are suggested by the presence of biominerals. This induced biomineralization includes fine clay films on the surface of the diatoms as well as associated granules and microcristals. The microscopic analysis of the diatom community suggests its effective participation on the biogeochemical processes at the sediment-water interface of mangrove forests.