Distribution of living benthic foraminifera in relation with environmental variables within the Aiguillon cove (Atlantic coast, France): improving knowledge for paleoecological interpretation

Abstract

Abstract Search for bioindicators in marine environments has provided new tools for monitoring global and local natural changes. Among these tools, benthic foraminifera play a central role. More accurate paleogeographical and paleoecological reconstructions become possible on the basis of the ecology of recent foraminifera. Nevertheless, factors acting on foraminiferal assemblages are still partially understood. The aim of this study is to correlate the distribution patterns of living (stained) benthic foraminifera with environmental variables such as tidal elevation, interstitial pore water salinity, organic matter content of the sediment, pheopigments, chlorophyll a, carbonate contents and grain size distribution of the sediment from 86 samples collected in the Aiguillon cove (France). In this paralic environment, sediment grain size, salinity and tidal elevation are fundamental factors that drive the distribution of the most abundant species i.e. Brizalina variabilis, Cribroelphidium excavatum and Haynesina germanica. Organic matter also influences the distribution patterns of benthic foraminifera: the relative abundance of Ammonia tepida is typically favored by an increase of total organic matter food resources. Chlorophyll a and pheopigments, as indicators of organic matter quality however may not be limiting in the proportion present in the Aiguillon cove. Carbonate proportions do not limit benthic foraminifera of the Aiguillon cove essentially with carbonaceous shells.