Benthic foraminifera for environmental monitoring: a case study in the central Adriatic continental shelf

A study of benthic foraminifera was carried out in sediment samples collected from the central Adriatic coast of Italy, near the Ancona harbour and the Falconara Marittima oil refinery, in order to validate and support their use as bioindicators of ecosystem quality. On the basis of a principal component analysis (PCA), three biotopes (following the bathymetric gradient) have been documented, showing that the distribution pattern of benthic foraminifera is principally related to riverine inputs, organic matter contents at the seafloor, and sediment grain size. We observed higher abundances of opportunistic, low-oxygen tolerant taxa along the coastline, thus being representative of polluted environmental conditions. Near the Falconara Marittima oil refinery, the microfaunal assemblages is characterized by the absence of living specimens and by a low diversity associated with the dominance of opportunistic species. At this site, aberrant tests were also found. The data point out that Ammonia parkinsoniana and Quinqueloculina seem to be the most sensitive taxa and can be considered as good bioindicators of environmental stress in this area. This study confirms that faunal composition and morphology of benthic foraminifera respond to human-induced environmental perturbations, making their study potentially useful for biomonitoring in coastal-marine areas.