Diatom assemblages from surface sediments of the Río de la Plata estuary, Uruguay

The Río de la Plata estuary (RdlP) exhibits environmental gradients associated with the freshwater input and oceanic water intrusion. The aim of this study was to assess diatom species distribution in surface sediment samples related to such environmental gradients. The internal section of RdlP was dominated by Aulacoseira spp., Eunotia spp., Staurosirella martyi, Actinocyclus normanii and Thalassiosira baltica, indicatives of low salinity levels and high trophic conditions, associated with the riverine and estuarine regimes. The external section was dominated by Coscinodiscus radiatus, Thalassiosira spp., Paralia sulcata, Cyclotella striata, among other marine taxa, indicatives of high salinity and low trophic conditions, associated with the influence of the Southwestern Atlantic Ocean. Furthermore, the intermediate section presents a mixture of both diatom groups representing mixing conditions. The observed diatom species groups capture fairly well the RdlP environmental variability and can be reliably used for paleoenvironmental studies in this and other similar estuarine systems. Fil: Perez, Laura. Universidad de la República; Uruguay Fil: Brugnoli, Ernesto. Universidad de la República; Uruguay Fil: Muniz, Pablo. Universidad de la República; Uruguay Fil: Sunesen, Inés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Sar, Eugenia Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Crisci, Carolina. Universidad de la República; Uruguay Fil: Cuña Rodriguez, Carolina Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentina Fil: Garcia Rodriguez, Felipe. Universidad de la República; Uruguay