Preliminary data on benthic foraminiferal assemblages (EU Momar project) coming from coastal areas of Sardinia (Cagliari gulf, Portoscuso, La Maddalena, Porto Torres)

A preliminary study on shallow-water living benthic foraminifera from several coastal areas of Sardinia (Cagliari Gulf, Portoscuso, La Maddalena and Porto Torres) has been carried on within a research project “EU MOMAR”, in order to have information on the environmental quality of these areas. MOMAR (Integrated System for Monitoring and control of the Marine Environment) aims to develop a common system of marine environmental monitoring in Tuscany, Sardinia and Corsica. This project improves accessibility and cross-border cooperation for the exploitation of natural resources through an integrated scientific plan, in order to analyze the coastal marine ecosystem and the pressures on it to prevent and recognize dynamics of environmental emergencies. In this project, the aim of our researches is to investigate the effects of enhanced anthropogenic activities on living benthic foraminifera analyzing the composition, diversity and distribution of the assemblages. On the basis of preliminary researches (work in progress), the spatial distribution of the foraminiferal assemblages and the geochemical data allow to distinguish from highly to less stressed environments in the studied areas. A total of 55 surface sediment samples were collected till now with a Van Veen grab sampler during the spring 2010. The foraminifera fauna is composed mainly by calcareous benthic taxa. Biotic indexes have showed that the characteristics of the assemblages range across the studied areas. Fisher-α index and Foraminiferal density drastically decrease in the samples characterized by high pollutants concentrations showing a possible control on the abundance and on taxonomic composition of the living foraminiferal assemblages. The morphological abnormalities observed in foraminiferal tests are mainly due to pathological morphogenesis related to ecological stress. The most abundant taxa coming from Cagliari Gulf samples are Ammonia tepida, Brizalina spathulata and B. striatula, whereas from Portoscuso samples are Quinqueloculina ungeriana, Peneroplis pertusus and Ammonia tepida, from Porto Torres samples are Ammonia tepida, Peneroplis pertusus and Brizalina striatula and from La Maddalena samples are Peneroplis pertusus, Brizalina striatula and Rosalina globularis. Among these dominant species, Ammonia tepida and bolivinids appear tolerance to environmental disturbance and pollution and are therefore particularly suitable as bio-indicators in coastal areas. The sampling sites characterized by better environmental conditions present an epiphytic biocoenosis with species that generally live in bottom sediment rich in vegetation, especially on leaves of Posidonia oceanica, as Lobatula lobatula, Planorbulina mediterannensis, Elphidium crispum and peneroplids. Living benthic foraminifera distribution patterns will be correlated to grain-size analysis, pollutant values and geochemical bottom sediment properties. Micropaleontological data, heavy metals and organic matter contents will be analyzed both with bivariate (correlation matrix), multivariate techniques of principal component analysis (PCA) and cluster analysis.