The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet—undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular, the Strait of Gibraltar and the adjacent Alboran Sea), western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well

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Vegetable oil tansesterification in supercritical conditions using Co-solvent carbon dioxide over solid catalysts: A screening study

The transesterification reaction employing supercritical methanol and carbon dioxide used as a co-solvent in the presence of several heterogeneous solid acid catalysts was investigated. The solid acid catalysts were prepared by impregnation methods, with appropriate precursors over magnesium aluminum silicate (cordierite). The catalysts tested were CeO2, WO3, ZnO, ZrO2, ZrO2-SO42-, mixed oxides (50-5096, w/w) WO3- ZrO2, CeO2-ZrO2, ZnO-La2O3, and Al2O3. Reaction tests were conducted at 200 degrees C and 20 MPa under the condition of 25:1 methanol/oil ratio at a space velocity of 4 mm with a fixed-bed continuous flow reactor containing ca. 5 g of catalyst. The best catalytic performance was obtained over ZrO2-SO42- with a yield toward fatty acid methyl esters (FAMEs) of 98%. This value is better to that obtained over the commercial catalyst Nafion SAC-13 (94%). The direct correlation between the conversion and catalyst total acidity was non-existent, but a positive effect of strong acid sites is evidenced.Postprint (published version

Vegetable oil tansesterification in supercritical conditions using Co-solvent carbon dioxide over solid catalysts: A screening study

The transesterification reaction employing supercritical methanol and carbon dioxide used as a co-solvent in the presence of several heterogeneous solid acid catalysts was investigated. The solid acid catalysts were prepared by impregnation methods, with appropriate precursors over magnesium aluminum silicate (cordierite). The catalysts tested were CeO2, WO3, ZnO, ZrO2, ZrO2-SO42-, mixed oxides (50-5096, w/w) WO3- ZrO2, CeO2-ZrO2, ZnO-La2O3, and Al2O3. Reaction tests were conducted at 200 degrees C and 20 MPa under the condition of 25:1 methanol/oil ratio at a space velocity of 4 mm with a fixed-bed continuous flow reactor containing ca. 5 g of catalyst. The best catalytic performance was obtained over ZrO2-SO42- with a yield toward fatty acid methyl esters (FAMEs) of 98%. This value is better to that obtained over the commercial catalyst Nafion SAC-13 (94%). The direct correlation between the conversion and catalyst total acidity was non-existent, but a positive effect of strong acid sites is evidenced

Biological patterns and ecological indicators for Mediterranean fish and crustaceans below 1,000 m: a review

19 páginas, 3 figuras, 6 tablasThe Mediterranean Sea is a relatively deep, closed sea with high rates of fisheries exploitation. In recent years fishing activity has tended to shift towards deeper depths. At the same time, the Mediterranean displays some rather special hydrographic and biogeographic conditions. The present paper reviews the present state of knowledge of the fisheries, biology, and ecology of the deep-sea fish and crustacean species in the Mediterranean dwelling below 1,000 m with potential economic interest, placing special emphasis on the western basin, for which more data are available, as a basis for future studies of the ecology, biodiversity, and effects of climate change and exploitation in this zone. This review reveals that mediterranean deep-sea fishes and crustaceans employ highly conservative ecological strategies, and hence the low fecundity and low metabolic rates in a stable environment like the deep-sea make these populations highly vulnerable. Moreover, ripe females of the main species mentioned here concentrate in the deepest portions of their distribution ranges. Deep-sea fish and crustaceans have high trophic levels and low to medium omnivory index values. The ecological indices discussed here, in combination with the limited knowledge of deep-sea ecosystems, clearly call for an approach based on the Precautionary PrincipleThe authors would like to thank the Captains and crews of R/V ‘‘García del Cid’’ (CSIC) for their technical support, and Mr. J. Rucabado and Dr. D. Lloris as the pioneers in using the otter bottom trawl as a sampling scientific method in the Mediterranean deep-sea. M. Coll has been founded by a postdoctoral fellowship from the Ministerio de Ciencias e Innovación from SpainPeer reviewe