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Numerous anthropogenic activities take place within or nearby ports, thereby increasing environmental pressure in coastal zone that become the final destination of many environmental contaminants. Thus, port areas are crucial to understand the possible long-term effects of contaminants on metazoans that are at the base of the food webs. The port of Vado Ligure is the outlet to the sea of one of the largest industrial areas of the West Liguria (NW Mediterranean). Sediment quality was evaluated in twenty-eight stations at increasing distance from the port. The nematode fauna was characterised (i.e., assemblage composition, taxonomic diversity and functional traits) and organic matter quantity and composition and contaminant concentrations (heavy-metals, polycyclic aromatic hydrocarbons and heavy, long-chain hydrocarbons) were measured. The area resulted mainly polluted by mercury, followed by arsenic, zinc, and polycyclic aromatic hydrocarbons. The faunal distribution (both from a taxonomical and functional point of view) appeared influenced by the contamination, as well as by sediment granulometry and organic matter content and composition. According to nematode assemblages and environmental variables, two groups of stations showed the most marked differences: one located in front of the Vado Ligure port, characterised by the most contaminated stations, the highest organic matter content, and fine sediments, and the other one, close to Bergeggi Marine Protected Area, characterised by more pristine stations, low organic matter content and coarser sediments. A suite of nematode genera that may be considered as bioindicators of pollution and organic enrichment was selected. Maturity index (MI) resulted negatively affected by contamination, suggesting that the different proportion of the nematode life-strategies is useful in assessing the environmental quality of sediments. The ecological quality status of the sampled stations obtained using abiotic and biotic descriptors (i.e., contamination level, organic matter content and nematode diversity and maturity index) was compared. Both the abiotic and nematode variables showed a general consistency for the stations of the two groups characterised by the highest and the lowest levels of contamination and organic enrichment.

Meiofauna in sediments colonized by Posidonia oceanica in the Ligurian Sea (NW Mediterranean) was investigated to evaluate its use as an early warning indicator of environmental disturbance. Descriptors commonly used in seagrass health assessment are mainly related to the plant (e.g., phenological parameters) and/or to the meadow (e.g., structural parameters) and are subjected to long-term response times. Conversely, meiofauna is considered a good bioindicator with a rapid response to environmental variations, due to its main features (e.g., short life cycle, scarce mobility, presence/absence of tolerant/sensitive species). Meiofaunal community, sediment characteristics and organic matter descriptors in three meadows located in urbanized coastal areas were contrasted with those observed in three meadows located within Marine Protected Areas. Samplings were carried out in two distinct periods, at the beginning and at the end of the summer season, in order to individuate early changes in the meiofaunal assemblages. The meiofauna and, particularly, the nematode assemblage composition and diversity, highlighted differences among meadows at the end of the summer not detectable by organic matter descriptors and structural parameters of the meadow (e.g. shoot density). Nematodes are, thus, proposed as appropriate biological quality elements (BQEs) able to show early responses to environmental disturbance.

The organic allochthonous material input in the benthic system of a NW Mediterranean shelf area was studied using a three-pronged approach, focusing firstly on the evaluation of the sedimentary stable isotope ratios and organic matter (OM) composition, then on the OM recycling processes performed by the microbial organisms, and finally on the potential trophic relationships between the macrobenthic organisms. The highest allochthonous signal, indicating continental input, was observed within the 50-m isobath, while at the 80-m isobath the marine signal was higher, pointing to a rather low continental influence approximately 5 km from the shore. Heavier rainfall, often generating abrupt allochthonous inputs by river outfalls, led to a wider spread of fine sediment particles. Carbohydrates were the compounds that best represented the continental input and these compounds were associated with potential recycling activities by microbiota, pointing to the entry of these C-containing allochthonous materials into the microbial food web. The macrofaunal deposit-feeders used sedimentary OM characterised by a continental signature as a food source, although the isotopic ratios of the organisms also pointed to selective feeding on materials that had a marine signature, especially at our offshore sampling stations. Predators fed on deposit- or suspension-feeders, with a potential selection of the latter during the highest inputs of continental materials occurring in winter.

Nematode biomass and allometric attributes (size spectra, body length and width, morphotypes) were measured and related to the environmental quality of sediments of the Genoa-Voltri commercial harbour (Ligurian Sea, NW Mediterranean) to investigate their possible use as ecological indicators. The sediment quality was defined by measuring the level of organic enrichment (quantity and biochemical composition of sedimentary organic matter) and oxygen stress (redox potential). Nematode biomass spectra (NBS) proved to be extremely valuable in determining differences in the environmental quality of sediments on a hundred-metre spatial scale. High peaks of the NBS were observed in the more organic-rich and oxygen-stressed stations probably in relation to a lower diversity of the nematode communities in these stations, with the predominance of tolerant genera such as Paracomesoma and Sabatieria. Among allometric variables, the length was found to be negatively correlated with oxygen concentrations and positively with TOM percentages, whilst the morphotype length/width ratio (L/W) resulted negatively related to oxygen concentrations and organic matter quality (protein:carbohydrate ratio), suggesting that these allometric attributes represent indicators of the functional adaptation of nematodes to the changing environmental conditions. We suggest that in contrast to time-consuming and expertise-requiring nematode taxonomic analysis, biomass and allometric attributes analysis can provide a simpler but comparable tool to assess sediment quality and environmental heterogeneity of harbour ecosystems.

The spatial distribution and structure of nematode assemblages in the area surrounding the harbour of Vado Ligure (Savona, NW Mediterranean) were studied in relation to the influence of natural and anthropogenic environmental factors. Stations were selected following an “anthropogenic gradient” from sites located near the city centre and its harbour to more pristine and distant sites. Sediment quality was determined by considering both sediment granulometric and chemical parameters (hydrocarbons, heavy metals, total organic matter, proteins, carbohydrates) as well as nematode abundance, diversity, life strategies, trophic structure and assemblage composition. A high correlation between environmental characteristics and the nematode response was found. On the basis of the comparison of these results, which identified three distinct sub-areas associated with different levels of environmental quality, a set of nematode indicator genera was selected for the future evaluation of quality status.

The different components of the benthic community of a sandy microtidal beach (Arenzano) in Liguria (NW Mediterranean) were investigated during late spring (May) 2002 and 2003. Sampling was carried out in two transects, chosen in order to represent the characteristics of the entire beach and their eventual spatial variations. Each transect included two stations: one placed in the swash zone (SW) and one in the surf zone (SF). Although no significant differences were found in the sediment texture over the 2 years (t-tests p > 0.1 for all the granulometric fractions), notwithstanding an increase in the mean grain size (from 0.8 to 1.1 mm) between the sampling periods, 2002 was characterised by a higher quantity of organic matter (on average 14.4 vs. 3.6 gC m−2 for the sum of proteins, carbohydrates and lipids) and higher bacterial biomass (on average 1.9 vs. 0.9 gC m−2). The metazoan assemblages (meiofauna and macrofauna) were also richer (density = 2.9 × 105 vs. 1.0 × 105 ind. m−2, biomass = 0.09 vs. 0.03 gC m−2 for meiofauna; density = 1988 vs. 739 ind. m−2, biomass = 0.14 vs. 0.03 gC m−2 for macrofauna) in 2002. A significant quantitative reduction (t-test for proteins, carbohydrates and lipids, at least p = 0.004) in the food supply in 2003 affected the abundance of the metazoans, as confirmed by a multivariate analysis that clearly differentiated the 2 years, and seemed to inhibit their relationships within the benthic food web. The bacterial biomass was always dominant, even under the least favourable trophic conditions, due to the ability of bacteria to adapt to a very harsh environment. Our results suggest that the food supply played an important role in the benthic community structures of the beach during late spring, bacteria being the key organisms within the benthic system. The communities seemed to be bottom-up controlled, while predation seemed to be irrelevant.