The biodiversity of the megabenthic assemblages of the mesophotic zone of a Tyrrhenian seamount (Vercelli Seamount) is described using Remotely Operated Vehicle (ROV) video imaging from 100 m depth to the top of the mount around 61 m depth. This pinnacle hosts a rich coralligenous community characterized by three different assemblages: (i) the top shows a dense covering of the kelp Laminaria rodriguezii; (ii) the southern side biocoenosis is mainly dominated by the octocorals Paramuricea clavata and Eunicella cavolinii; while (iii) the northern side of the seamount assemblage is colonized by active filter-feeding organisms such as sponges (sometimes covering 100% of the surface) with numerous colonies of the ascidian Diazona violacea, and the polychaete Sabella pavonina. This study highlights, also for a Mediterranean seamount, the potential role of an isolated rocky peak penetrating the euphotic zone, to work as an aggregating structure, hosting abundant benthic communities dominated by suspension feeders, whose distribution may vary in accordance to the geomorphology of the area and the different local hydrodynamic conditions.
This study analysed the anthropogenic microparticles in the stomach content of the European anchovy (Engraulis encrasicolus) in the Ligurian Sea (NW Mediterranean). The results showed that 30–40% of the anchovies had ingested anthropogenic microparticles (on average, 0.34 ± 0.29 fibres ind−1 and 0.12 ± 0.12 fragments ind−1). The fibres were probably ingested via filtration, and were significantly correlated with the gut fullness. Fibres were mostly dark, but the presence of other colours was frequent, indicating a general lack of selectivity. Plastic fragments composed of polyethylene and polypropylene were prevalently transparent, suggesting active predation, especially for larger fragments resembling zooplankton. No significant differences were recorded for the frequency of fish containing particles among females, males, and undetermined individuals. The presence of, generally, only one anthropogenic item per fish, as observed for 95.8% of fish containing microparticles, indicated that the permanence of these particles in the stomachs was short, likely no more than 1 day, although it could also depend on low environmental concentrations. The evaluation of the intestinal lumen indicated that a portion of the plastic fragments found in the stomach could not be ejected. Hard fragments that were larger than the intestinal lumen could be held for longer times, but probably regurgitation, fragmentation, and embedding in a biological matrix may facilitate their quick elimination. It is pivotal to understand the processes that regulate the abundance and the residential time of anthropogenic particles in commercial organisms captured for human nutrition, given the potential biomagnification of toxic substances carried by ingested particles.
As part of the Ross Sea Marginal Ice Zone Ecology Project (ROSSMIZE) the summer organic matter flux through the water column was measured at 40 m depth in Terra Nova Bay. Water samples and material from a sediment trap on the sea-bottom were analysed for their biochemical composition. A close coupling between biochemical composition of the organic matter in the water column and the material collected in the sediment trap was found, resulting from complex interactions between physical and biological processes. The physical processes are related to break-up and melting of the ice cover and occur mainly in the early summer season, whilst biological processes play a key role in mid summer and, from the evidence from faecal pellets, are related to the primary production and consumption processes.