Free-living nematodes were investigated in the Mar Piccolo of Taranto (Ionian Sea), a semi-enclosed basin of strategic importance for its complex productive infrastructure but in need of remediation due to the alarming amounts of heavy metals and synthetic organic contaminants in the sediments. Abundance, genera composition, biodiversity and trophic traits of nematodes were related to the gradual transition from marine to more brackish conditions and to the varying levels of contaminants in different sub-areas of the basin. Nematodes were more abundant and diverse at the most marine site while low numbers and diversity characterized the most contaminated station. Going towards the innermost part of the basin, gradually increasing values of abundance and biodiversity were observed although the assemblage was susceptible to the organic enrichment caused by mussel farms. The use of nematodes as ecological indicators mirrored the response of the assemblage to the main patterns acting in the basin (High/Good scores at the most marine site and Poor/Bad scores at the most contaminated station), giving a clear indication of environmental quality to stakeholders/authority that can contribute to address remediation actions in contaminated sediments.

The benthic diversity of the soft bottoms in the Taranto Seas (Mar Grande and Mar Piccolo) (eastern-central Mediterranean Sea) was studied during July 2002. Quantitative samples were taken using a Van Veen grab and granulometric analysis of the sediment was carried out. A total of 131 species were identified. Molluscs and annelids made up 77% of the species and 87% of the individual number. Data from these two groups were used for hierarchical clustering and multidimensional scaling. The diversity was calculated using the rarefaction method. Two main benthic species assemblages were identified. The first corresponded to the stations characterized by pelitic sediment and located in the Mar Piccolo, the second was made up by the stations with pelite with increasing percentages of sand and distributed in the Mar Grande. The first assemblage consisted of species that usually live on muddy bottoms rich in organic matter; the second consisted of a greater number of species, usually occurring on different types of bottoms. Diversity was found to be higher in the Mar Grande than in the Mar Piccolo, indicating that physico-chemical alterations of the environment probably play a leading role in controlling community structure.