Hydrodynamic forcing and sand permeability influence the distribution of anthropogenic microparticles in beach sediment

The distribution of anthropogenic microparticles (Mps), such as plastic and natural fibres used in textiles, in beach sediments was studied in a human-influenced pocket beach in Liguria (NW Mediterranean Sea). Information on environmental parameters such as rainfall, hydrodynamic characteristics and sediment texture was collected at the same time as the sediment samples. The Mps (416 +- 202 Mps kg-1 on average) were mainly fibres (57\u2013100%), while fragments and spheres showed irregular abundances linked to the draining action of waves on the beach. Uni- and multivariate statistical analyses highlighted that the different spatial and seasonal distribution of fibres primarily depended on the action of the waves that force seawater into the sand, rather than on sedimentation following depositional processes. Wave height and direction had a role in fibre distribution in the sand, as well as sediment permeability and sorting. The occurrence of short-term and spatially-localised hydrodynamic events such as rip currents were observed to influence the abundance of fibres, overlapping the seasonal sequences of beach accretion and erosion that is typical of the area and increasing fibre abundance by transporting those accumulated in the sediments of the submerged beach during winter

Macrofaunal assemblages in canyon and adjacent slope of the NW and Central Mediterranean systems

Macrofaunal assemblages were studied along bathymetric transects in six canyons and four adjacent open slopes of the Mediterranean Sea. The different areas investigated were located approximately along a longitudinal gradient at similar latitudes. Three regions were investigated: the Catalan (from 334 to 1887 m depth), the Ligurian (from 222 to 2005 m depth) and the South Adriatic margins (from 196 to 908 m depth). The analysis of the meso-scale distribution of assemblage structure and biomass showed significant differences among regions, which resulted in high values of \u3b4-diversity. Clear differences in trophic composition were also observed, and a decreasing pattern in the individual body size of macrofaunal organisms moving Eastward. These patterns were apparently linked to changes in food supply, whereas macrofaunal abundance and number of taxa showed a decrease pattern with increasing water depth. When the assemblage structure was compared between canyons and adjacent open slope, a very high \u3b2-diversity was observed, indicating that the bottom topography exerted a strong effect on the assemblage characteristics

The allochthonous material input in the trophodynamic system of the shelf sediments of the Gulf of Tigullio (Ligurian Sea, NW Mediterranean)

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

Meio- and macrofauna in the marine area of the Monte St. Bartolo Natural Park (Central Adriatic Sea, Italy)

This paper presents an integrated investigation of benthic foraminiferal, meiofaunal and macrofaunal assemblages that was carried out in front of the marine area of the Monte St. Bartolo Regional Natural Park (Adriatic Sea, Italy). Although this area is not yet subject to conservation plans, an overall good quality status of its benthic assemblages was documented. In particular, the assemblages were somewhat diversified and generally minimally to moderately affected by anthropogenic activities. Both the foraminifera and macrofauna seemed to be primarily influenced by variations in the habitat's features, whereas significant changes in the meiofaunal assemblage were related more to trophic supply fluctuations. These data suggest the potential vulnerability of this area and highlight the importance of defining and applying an appropriate integrated zone management plan