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Moya F.,Spanish Oceanographic Institute | Saucede T.,University of Burgundy | Manjon-Cabeza M.E.,University of Malaga
Polar Biology

The Bellingshausen Sea is one of the most remote and least surveyed seas of the Southern Ocean, so that little was known about benthic communities and those factors that determine community structuring until recently. The present work aims at characterizing the structure and spatial distribution of echinoid assemblages in the Bellingshausen Sea, as well as identifying the environmental factors that determine assemblage structuring. Echinoids were collected at 32 stations using an Agassiz trawl, at depths of 86-3,304 m, during BENTART oceanographic expeditions led in 2003 and 2006. Sediment and bottom water properties were analysed using an USNEL-type box corer and a Neil Brown Instrument System Mark III CTD, respectively. Echinoids were found at all stations, except Peter I Island. Seventeen species were identified, representing 22 % of the echinoid species present in the Southern Ocean and increasing twofold the number of species recorded in the Bellingshausen Sea so far. The echinoid fauna is dominated by the very abundant species Sterechinus antarcticus. Depth is the key factor that determines the nature of echinoid assemblages, which are mainly divided into the continental shelf, the slope and the deep-sea basin. In addition, sediment properties, namely redox values, organic matter and mud content, best match species dispersion on the shelf. Sediment properties affect echinoid distribution depending on species food range and feeding strategy. As it might be expected, sediment properties more strongly influence specialist feeders (Schizasteridae and Cidaridae) than generalists (Echinidae). © 2012 Springer-Verlag. Source

Galindo-Villegas J.,University of Murcia | Mulero I.,University of Murcia | Garcia-Alcazar A.,Spanish Oceanographic Institute | Munoz I.,University of Murcia | And 5 more authors.
Fish and Shellfish Immunology

Vibrio anguillarum is the main causative agent of vibriosis in cultured sea bass. Unfortunately, available vaccines against this disease do not achieve the desired protection. In this study, to accomplish uptake, processing, and presentation of luminal antigens, a commercial sea bass oral vaccine against V.anguillarum was improved with the addition of recombinant fish-self tumor necrosis factor α (rTNFα), as adjuvant. To explore mechanisms, systemic and local responses were analyzed through serum specific IgM titers, gene expression, lymphocytes spatial distribution in the gut, and invitro functional assays. We found along the trial, over expressed transcripts of genes encoding cytokines and antimicrobial molecules at the gut of rTNFα supplied group. Orally immunized fish with vaccine alone confer protection against V.anguillarum challenge throughout a short time period. In contrast, adjuvant-treated group significantly extended the response. In both cases, achieved protection was independent of serum IgM. Yet, IgT transcripts were found to increase in the gut of rTNFα-treated fish. More importantly, fish treated with rTNFα showed a dramatic change of their T lymphocytes distribution and localization in gut mucosal tissue, suggesting specific antigen recognition and further intraepithelial T lymphocytes (IEL) activation. To determine the mechanism behind IEL infiltration, we characterized the constitutive and activated pattern of chemokines in sea bass hematopoietic tissues, identifying for the first time in fish gut, an intimate relation between the chemokine ligand/receptor CCL25/CCR9. Ex-vivo, chemotaxis analyses confirmed these findings. Together, our results demonstrate that improved oral vaccines targeting key cytokines may provide a means to selectively modulate fish immune defence. © 2013 Elsevier Ltd. Source

von Appen W.-J.,Alfred Wegener Institute for Polar and Marine Research | Schauer U.,Alfred Wegener Institute for Polar and Marine Research | Somavilla R.,Alfred Wegener Institute for Polar and Marine Research | Somavilla R.,Spanish Oceanographic Institute | And 2 more authors.
Deep-Sea Research Part I: Oceanographic Research Papers

Current meters measured temperature and velocity on 12 moorings from 1997 to 2014 in the deep Fram Strait between Svalbard and Greenland at the only deep passage from the Nordic Seas to the Arctic Ocean. The sill depth in Fram Strait is 2545. m. The observed temperatures vary between the colder Greenland Sea Deep Water and the warmer Eurasian Basin Deep Water. Both end members show a linear warming trend of 0.11±0.02. °C/decade (GSDW) and 0.05±0.01. °C/decade (EBDW) in agreement with the deep water warming observed in the basins to the north and south. At the current warming rates, GSDW and EBDW will reach the same temperature of -0.71. °C in 2020. The deep water on the approximately 40. km wide plateau near the sill in Fram Strait is a mixture of the two end members with both contributing similar amounts. This water mass is continuously formed by mixing in Fram Strait and subsequently exported out of Fram Strait. Individual measurements are approximately normally distributed around the average of the two end members. Meridionally, the mixing is confined to the plateau region. Measurements less than 20. km to the north and south have properties much closer to the properties in the respective basins (Eurasian Basin and Greenland Sea) than to the mixed water on the plateau. The temperature distribution around Fram Strait indicates that the mean flow cannot be responsible for the deep water exchange across the sill. Rather, a coherence analysis shows that energetic mesoscale flows with periods of approximately 1-2 weeks advect the deep water masses across Fram Strait. These flows appear to be barotropically forced by upper ocean mesoscale variability. We conclude that these mesoscale flows make Fram Strait a hot spot of deep water mixing in the Arctic Mediterranean. The fate of the mixed water is not clear, but after the 1990s, it does not reflect the properties of Norwegian Sea Deep Water. We propose that it currently mostly fills the deep Greenland Sea. © 2015 The Authors. Source

Acosta J.,Spanish Oceanographic Institute | Fontan A.,Spanish Oceanographic Institute | Munoz A.,Tragsa SGP | Munoz-Martin A.,Complutense University of Madrid | And 2 more authors.
Marine and Petroleum Geology

Multi-beam bathymetry and high-resolution low-penetration seismic reflection profiles of the offshore extensions of the Bétic Internal Zone off Sierra de Cartagena-La Unión margin along its south side and the Mar Menor margin along its east side, the Mazarrón Escarpment forming its southern boundary and the adjacent oceanic Algero-Balearic basin have provided images of the neo-tectonic structures of the region equal to those provided by subaerial photography. For the first time we mapped with unprecedented detail the Mazarrón Escarpment and the Southeast margin of Iberia.The first-order structures of the region are due to the consequence of the collision of the African and Eurasian plates during the Alpine orogeny in late Oligocene-Middle Miocene, the westward migration of the Alborán plate in the Middle Miocene and the desiccation of the Mediterranean in the Messinian (Late Miocene) that led to the deposition of evaporites in the Algero-Balearic basin and erosion of the Mazarrón Escarpment, the Sierra de Cartagena-La Unión shelf, the Mar Menor margin and the adjacent coast. Our data images second order tectonic features (neo-tectonic features) superimposed on the larger structures. These include the deformation of the strata in the Algero-Balearic basin by the gliding of the Plio-Quaternary sediments on Messinian halite on the margins of the basin and sediment loading in its center, the Late Miocene-Quaternary deformation of the area north of the Mazarrón Escarpment resulting from the continuous oblique convergence of the African and Eurasian plates in a NNW-SSE direction, the Miocene to Pleistocene volcanic edifices and pinnacles (dikes), the pockmarks formed by the extrusion of gas/water via faults and the massive gravitational failure of the Mazarrón Escarpment triggered by this plate convergence. The data also show in detail features formed on the Mazarrón Escarpment during the Messinian, Pliocene and Pleistocene regressions and those on the shelf formed during the Pleistocene glacially induced regressions/transgression and sediment drifts generated by modern currents. © 2013 Elsevier Ltd. Source

Coelho R.,University of Algarve | Coelho R.,University of Florida | Rey J.,Spanish Oceanographic Institute | Gil de Sola L.,Spanish Oceanographic Institute | And 3 more authors.
Marine Biology Research

Etmopterus spinax is a small-sized deep-water lantern shark that occurs in the Eastern Atlantic and the Mediterranean. Differences in depth distribution, densities, size at maturity and fecundity were compared between a population that has suffered high levels of fishing mortality during the last decades (Southern Portugal in the northeast Atlantic) and a population where low fishing pressure below 500 m occurs at present or has occurred in the last decades (Northern Alboran Sea in the western Mediterranean). The density of this species, as derived by experimental bottom trawl survey, off the coast of Southern Portugal, is substantially lower than in the Northern Alboran Sea throughout the entire depth range. The Atlantic population is maturing at smaller sizes than the Mediterranean population and has a lower mean fecundity. Specifically, sizes at maturity for Southern Portugal and the Northern Alboran Sea were, respectively, 25.39 and 28.31 cm TL for males and 30.86 and 34.18 cm TL for females, while mean fecundities for Southern Portugal and the Northern Alboran Sea were, respectively, 9.94 and 11.06 oocytes per mature female. This work demonstrated the possible presence of density-dependent mechanisms in the Southern Portuguese population of E. spinax that has lowered the size at maturity as a possible result of excessive fishing mortality. However, given that this is an aplacentary viviparous shark, where fecundity is dependent on female size, this compensatory mechanism seems to have a limited efficiency. © 2010 Taylor & Francis. Source

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