Total benthic foraminifera assemblages in the southwestern Spanish estuaries

One hundred and twenty-one samples were collected in three estuaries of the Huelva littoral (SW Spain). The 12,923 individuals picked were assigned to forty-seven species. The analysis of the foraminiferal percentages allows the distinction of seven assemblages: two salt marsh assemblages ( Trochammina inflata and Jadammina macrescens ), four assemblages widely represented both in the channel margins and the channels ( Ammonia inflata, Astrononion stelligerum, Cribroelphidium vadescens, Ammonia ammoniformis ) and one marginal marine assemblage ( Ammonia beccarii-Quinqueloculina spp). The distribution of these assemblages is controlled by the salinity, the altitude above the lowest tidal level and, to a lesser extent, by the grain size, organic matter and the test transport. In the Tinto-Odiel estuary, both effects of heavy metal pollution and sedimentary changes in the foraminiferal distribution were analyzed, indicating some recuperation mainly in the Odiel river, one of the most polluted areas of the world.