1,721,105 research outputs found
Observations on some reproductive features of the threatened limpet Patella ferruginea Gmelin, 1791 in north-western Mediterranean Italian waters
No full textInformation about the reproductive biology of the threatened limpet Patella ferruginea has been historically restricted to some of the few enclaves where healthy and conspicuous populations still persist, all located on the African coasts of the Alboran Sea, at the extreme south west of the species' distribution range, in the western basin of the Mediterranean. This paper provides data on sex ratio by size and sex change of the species from specimens in the northernmost extreme of its distribution, between the north east of Sardinia (Italy) and the Gulf of Genoa (Liguria, Italy), where much more restricted and small populations are found. In the study area, the population parameters were found to be quite similar to those known from the Alboran Sea: The ratio between males and females tends to decrease with size and the prevalence of females versus males (i.e. >50% females) from the 60-65 mm size class upwards. Notwithstanding the small sample size (n = 13), several sex changes were observed in 38.5% of specimens. Noteworthy is that this change not only occurred in the male to female direction (considered 'normal' for limpet species) but was also recorded in the female to male direction, confirming the complexity of the reproductive mode of P. ferruginea. The evidence of regular gonadal maturation of specimens and the occurrence of sex changes in the area investigated supports the potential viability of the species at its northernmost limit of distribution, where the species has only recently been reported. Such evidence provides important information for the implementation of management and conservation actions, such as restocking initiatives
7. Albertelli G., Cattaneo-Vietti R., Chiantore M., Pusceddu A., Fabiano M. Food availability to an Adamussium bed during the austral summer 1993/1994 (Terra Nova Bay, Ross Sea)
No full textAnthropogenic radionuclides bioaccumulation in Antarctic marine fauna and its ecological relevance
No full textRobustness of Adamussium colbecki shell to ocean acidification in a short-term exposure
No full textAtmospheric pCO2 has increased since the industrial revolution leading to a lowering of the ocean surface water pH, a phenomenon called ocean acidification (OA). OA is claimed to be a major threat for marine organisms and ecosystems and, particularly, for Polar regions. We explored the impact of OA on the shell mechanical properties of the Antarctic scallop Adamussium colbecki exposed for one month to acidified (pH 7.6) and natural conditions (unmanipulated littoral water), by performing Scanning Electron Microscopy, nanoindentation and Vickers indentation on the scallop shell. No effect of pH could be detected either in crystal deposition or in the mechanical properties. A. colbecki shell was found to be resistant to OA, which suggests this species to be able to face a climate change scenario that may threat the persistence of the endemic Antarctic species. Further investigation should be carried out in order to elucidate the destiny of this key species in light of global change
Loss of fucoid algae along a gradient of urbanisation and relationships with the structure of benthic assemblages
No full textCanopy-forming macroalgae of the genus Cystoseira are being lost in several areas of
the Mediterranean Sea. Cystoseira amentacea var. stricta and C. compressa are common species in
the Ligurian Sea; they are distributed in patches, but their abundance and distribution is locally variable.
We investigated changes in relative cover, biomass and morphology of Cystoseira amentacea
var. stricta and C. compressa with increasing urbanisation, and effects of the presence or absence of
Cystoseira species on the composition and structure of understorey assemblages. C. amentacea var.
stricta habitats were lost close to urban areas, while C. compressa slightly increased. The morphological
characteristics of these 2 species were very variable in space and time, and did not vary with
urbanisation. Assemblages lacking canopy differed markedly from Cystoseira-dominated assemblages,
particularly assemblages dominated by Corallina elongata, the species most responsive to
changes in habitat structure and urbanisation, which forms dense turfs in urban habitats lacking
canopies. Marked species-specific differences between the assemblages dominated by the 2 Cystoseira
species were detected. C. amentacea var. stricta is a key species maintaining habitat complexity
and species diversity in Mediterranean rocky shores and we recommend additional conservation
actions, such as habitat restoration by transplantation of this endangered species
Seasonal variations of susceptibility to oxidative stress in Adamussium colbecki, a key bioindicator species for the Antarctic marine environment.
No full textA new record of the invasive seaweed Caulerpa cylindracea Sonder in the South Adriatic Sea
No full textThe green alga Caulerpa cylindracea Sonder is one of the most infamous and threatening invasive species in the Mediterranean Sea. Since 1985, it started rapidly spreading to all Mediterranean regions causing many ecological changes on natural communities. In the present study, we present an example of this proliferation with the first record in the Marine Protected Area of Tremiti Island (MPATI) in the South Adriatic Sea. Fifteen sites along the coast and 5 different depths have been investigated. Our results provide eveidence of a wide invasion of this pest in three islands, San Domino, San Nicola and Capraia. This study fills a particular data gap in the ongoing biomonitoring of invasive seaweeds in the Mediterranean Sea representing a base line of this invasive species for the MPATI
Antarctic scallop (Adamussium colbecki) annual growth rate at Terra Nova Bay
No full textAdamussium colbecki is one of the most well-studied Antarctic molluscs. However, information on its growth rate is currently based on estimates from mark and recapture experiments and from growth-ring analyses. This paper provides the first estimates of the growth pattern of this scallop throughout a year, for individuals maintained under both natural field and laboratory conditions. Results show size-related differences in growth rate, both in the field and in aquaria, with scallops in Terra Nova Bay growing faster than those kept in aquaria. Growth performances were lower than those reported in the literature
Unusual trophic strategies of Hydractinia angusta (Cnidaria, Hydrozoa) from Terra Nova Bay, Antarctica
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