307 research outputs found
21 Mediterranean Black Coral Communities
No full textRemotely operated vehicle (ROV) investigations of the
Mediterranean deep continental shelf and bathyal zone
have provided, in the last decade, a large amount of data
concerning an enigmatic group of anthozoans: the black
corals. Taxonomic investigations as well as ecological
and biological studies contributed to unveil the diversity,
population structure, environmental preferences, bathymetric
and geographical distribution of these corals.
Remotely operated vehicle footage and accidental bycatch
data have provided evidences of large impact by fishing
activities on the Mediterranean black coral forests such
that today, due also to their important ecological role as
structuring species, they are considered part of vulnerable
marine ecosystems and conservation strategies need to be
developed targeting their protection
Population dynamics of Eudendrium racemosum (Cnidaria, Hydrozoa) from the North Adriatic Sea
No full textBenthic suspension feeders in shallow waters develop in relation to the food availability and the variation of physical parameters giving rise to complex communities that act as a control factor on the plankton biomass. The aim of the work is to establish the role of the hydrozoan Eudendrium racemosum in the energy transfer from the plankton to the benthos in marine food chains of the North Adriatic Sea. This study highlighted that the hydroid biomass changed over time in relation to temperature and irradiance, and the highest abundance was observed during summer with about 400,000 polyps m-2 (about 19 g C m-2). The population suffered an evident summer decrease in relation to a peak of abundance of its predator, the nudibranch Cratena peregrina, whose adult specimens were able to eat up to 500 polyps day-1 and reached an abundance of 10 individuals m-2. The gut content analysis revealed that the hydroid diet was based on larvae of other benthic animals, especially bivalves and that the amount of ingested preys changed during the year with a peak in summer when it was estimated an average predation rate of 13.7 mg C m-2 day-1. In July, bivalves represented over 60 % of the captured items and about 18 mg C m-2 day-1. Values of biomass of E. racemosum are the highest ever recorded in the Mediterranean Sea, probably supported by the eutrophic conditions of the North Adriatic Sea. Moreover, our data suggest that settling bivalves provide the greater part of the energetic demand of E. racemosum
Excavating sponges from the Adriatic Sea: description of Cliona adriatica sp. nov. (Demospongiae: Clionaidae) and estimation of its boring activity
No full textPrima segnalazione della specie tropicale Paraleucilla magna Klautau et al., 2004 (Porifera, Calcarea) nel Mar Ligure.
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FIGURE 6. Chondropsis subtilis n in Sponges associated with octocorals in the Indo-Pacific, with the description of four new species
No full textFIGURE 6. Chondropsis subtilis n. sp. A–B, Living sponge encrusting Carijoa riisei in situ. Note in B the pink massive sponge close to C. riisei might be the holotype of this species; C, Holotype encrusting several branches of C. riisei; D, Sand and spicules creating a fine and regular network on the sponge surface; E, Sponge surface showing a homogeneous layer of sand, foreign spicules and strongyles; F, Choanosomal skeleton of ascending tracts of spongin, embedded with sand grains, strongyles and foreign spicules; G, Straight and very thin strongyle; H, Very thin sigmas.Published as part of Calcinai, Barbara, Bavestrello, Giorgio, Bertolino, Marco, Pica, Daniela, Wagner, Daniel & Cerrano, Carlo, 2013, Sponges associated with octocorals in the Indo-Pacific, with the description of four new species, pp. 1-61 in Zootaxa 3617 (1) on page 13, DOI: 10.11646/zootaxa.3617.1.1, http://zenodo.org/record/24815
Excavating sponges from the Adriatic Sea: description of<i>Cliona adriatica</i>sp. nov. (Demospongiae: Clionaidae) and estimation of its boring activity
No full textBoring sponge diversity in the area of the Conero Promontory, the most important rocky emergence on the west coast of the Adriatic Sea (Italy), was assessed. Four species were recorded; one of them,Cliona adriatica, is new and is described here. The new species differs from all the other excavating sponge species, characterized by yellow papillae and lacking or scarcity of microscleres, in the large size of the boring chambers and the presence of numerous styles.Cliona adriaticais present on about 12% of the surface of rocky bottoms in the Conero Promontory area. The impact of this highly destructive species on the carbonatic micritic rock of the promontory was evaluated calculating a relationship between the volume of the boring chambers and the surface of the epilithic portions. Consequently, it was estimated that 1 cm2of epilithic tissue corresponds to 8.5 g of excavated rock. The recorded correlation between the excavated volume and the area of the papillar zone (roughly the area of the substratum affected by the erosion) allows an estimation of the substratum removed by a boring sponge, using only visually oriented, non-destructive, sampling methods.</jats:p
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