Meiobenthos and nematode assemblages from different deep-sea habitats of the Strait of Sicily (Central Mediterranean Sea)

Much attention is currently devoted at upgrading our knowledge on biodiversity and functioning of deep water ecosystems. Information is constantly enriched by researchers, even from basins as the long-studied Mediterranean Sea. In such a perspective, we studied meiobenthic and nematode communities inhabiting muddy sediments from three different habitats at bathyal depths in the Strait of Sicily: a cold-water coral site (CS) in the Maltese Coral Province, a muddy bottom in the same area (MS), and a hydrocarbon imprinted pockmark site (PS) in the Gela Basin. The average meiofauna density at CS (1343 ind/10 cm2) and MS (1804 ind/10 cm2) is much higher than that reported in literature for similar habitats; it is also markedly more elevated than that recorded at PS (224 ind/10 cm2). Although nematodes of the three sites show different abundances, they share similar assemblage structure. Nematodes (avg. 86%) and copepods (avg. 9.3%) were the most abundant meiofaunal taxa at all sites followed by annelids, kinorhynchs and turbellarians. Nematodes were composed by 21 families and 46 genera, with Terschellingia, as most abundant genus (12.4%), followed by Microlaimus (11%), Daptonema (11%), Thalassomonhystera (10.8%), Acantholaimus (9.5%) and Sabatieria (8.7%). The genera Thalassomonhystera, Terschellingia, Microlaimus, Daptonema, Chromadorita, Sabatieria, and Anticoma display a dominance in at least one station. The taxonomic structure of meiofaunal communities of the studied sites is rather similar but differences in relative abundance are evident

Quantitative dominances of taxa structuring the macrozoobenthic communities living in different coastal habitats.

The aim of this study was to quantify the dominance of macrozoobenthic taxa structuring the benthic assemblages associated to 6 coastal habitats, which occur from the mesolittoral to the circalittoral zone of the Campania coast. Crustaceans, polychaetes and molluscs were the main taxonomic groups structuring all the benthic assemblages, representing an average of 89.20% of the total taxa. However, each habitat showed the dominance of only one peculiar taxon

Meiofauna and nematode diversity in some Mediterranean subtidal areas of the Adriatic and Ionian Sea

Sediments of three different subtidal areas (15-705 m depth) of the Italian coasts (Manfredonia, Brindisi and Gallipoli) were investigated to study meiofauna and nematode composition. The nematodes were identified to the genus level and their abundances compared using multivariate analysis. Our data showed an evident depth gradient in meiofauna abundance: the shallowest sites had more diverse and abundant meiobenthic communities than the deeper ones. Nematodes were the dominant taxon (83-100%) at all sites, followed by Copepoda (0.5-8%). Sabatieria, Astomonema, Dorylaimopsis, Terschellingia and Daptonema were among the dominant nematode genera in the three areas. Nematode genus H’ diversities were not significantly dissimilar, though at community level some differences were detected among the study areas. The greatest differences were observed in the comparison of the communities from Manfredonia and Gallipoli. Furthermore, there was a difference between shallow (Astomonema, Dorylaimopsis, Sabatieria and Terschellingia)

Red coral (Corallium rubrum) populations and coralligenous characterization within "Regno di Nettuno MPA" (Tyrrhenian Sea, Italy)

Red coral is one of the most important species belonging to the coralligenous habitats, being a structuring organism and highly sensitive to human pressure. The presence of red coral populations is historically well documented along the Campania coast (Tyrrhenian Sea), and, due to its high economic value, it has been commercially overharvested since ancient times. Red coral populations along several cliffs on the "Regno di Nettuno" MPA of the Gulf of Naples were investigated using ROV-imaging techniques. Coralligenous habitats were characterized in terms of percent cover and number of morphological groups. Pizzaco site showed the richest and most diverse community. Density of red coral colonies was calculated and compared with morphometric parameters. Results show an inversely correlated trend between colonies density and their size. Finally, fishing pressure was estimated through frequency of lost fishing gears, and S. Angelo site resulted the most stressed one. Anthropic stress plays a key role in the degradation of coralligenous habitats and the dramatic reduction of red coral populations recorded in recent years allows to suspect a more extensive degradation of the entire community. An assessment of the distribution and state of the populations can provide useful information to take measures for a better MPAs management