Benthic foraminiferal assemblages as pollution proxiesin the northern coast of Gabes Gulf, Tunisia

摘要

A study of chemical and sedimen-tological parameters integrated with benthic foraminifera investigation was conducted along the northern coast of Gabes Gulf. Thirty-two samples were studied and a total of 68 benthic foraminiferal species were identified. Heavy metals enrichment factors and total hydrocarbon concentrations showed both metal and petro-genic pollution related mainly to phosphogypsum, sewage, and fishing activities. Statistical analysis (bivariate correlation and hierarchical cluster analysis) show a possible control of these pollutants on density, diversity, as well as the taxo-nomic composition of the benthic foraminiferal assemblages. The extent to which the population was found less dense and less diversified corresponded to the degree to which the sediment was contaminated. In these contaminated sites, an increase in relative abundance of opportunistic species such Ammonia tepida and Hay-nesina germanica was found. Far from pollution, foraminiferal assemblages are dominated by species characteristic of Mediterranean shallow water (Ammonia beccarii, Ammonia parkinsoni-ana, Elphidium crispum, Elphidium williamsoni, Elphidium advenum, Peneroplis planatus, Penero-plis pertesus).