Percorrer por autor "Martinez, P."
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- Comparative gene expression and histological analysis of skin response to injury in two congeneric flatfish with striking skin morphological differences, the brill (Scophthalmus rhombus) and the turbot (Scophthalmus maximus)Publication . Estêvão, J.; Millan, A.; Pardo, B. G.; Fernandez, C.; Rubiolo, J.; Herrera, M.; Gomez-Tato, A.; Ronza, P.; Cabaleiro, S.; Quiroga, M., I.; Power, Deborah; Martinez, P.Analysis of the morphological and genetic differences in the skin response to injury between Turbot and Brill.
- Genetic diversity and historical demography of Atlantic bigeye tuna (Thunnus obesus)Publication . Martinez, P.; Gonzalez, Elena G.; Castilho, Rita; Zardoya, R.Bigeye (Thunnus obesus) is a large, pelagic, and migratory species of tuna that inhabits tropical and temperate marine waters worldwide. Previous studies based on mitochondrial RFLP data have shown that bigeye tunas from the Atlantic Ocean are the most interesting from a genetic point of view. Two highly divergent mitochondrial haplotype clades (I and II) coexist in the Atlantic Ocean. One is almost exclusive of the Atlantic Ocean whereas the other is also found in the Indo-PaciWc Ocean. Bigeye tuna from the Atlantic Ocean is currently managed as a single stock, although this assumption remains untested at the genetic level. Therefore, genetic diversity was determined at the mitochondrial control region to test the null hypothesis of no population structure in bigeye tuna from the Atlantic Ocean. A total of 331 specimens were sampled from four locations in the Atlantic Ocean (Canada, Azores, Canary Islands, and Gulf of Guinea), and one in the Indian and PaciWc Oceans, respectively. The reconstructed neighbor-joining phylogeny conWrmed the presence of Clades I and II throughout the Atlantic Ocean. No apparent latitudinal gradient of the proportions of both clades in the diVerent collection sites was observed. Hierarchical AMOVA tests and pairwise ST comparisons involving Atlantic Ocean Clades I and II were consistent with a single stock of bigeye tuna in the Atlantic Ocean. Population genetic analyses considering phylogroups independently supported gene Xow within Clade II throughout the Atlantic Ocean, and within Clade I between Atlantic and Indo-PaciWc Oceans. The latter result suggests present uni-directional gene Xow from the Indo-PaciWc into the Atlantic Ocean. Moreover, mismatch analyses dated divergence of Clades I and II during the Pleistocene, as previously proposed. In addition, migration rates were estimated using coalescent methods, and showed a net migration from Atlantic Ocean feeding grounds towards the Gulf of Guinea, the best-known spawning ground of Atlantic bigeye tuna.
- The Congolobe project, a multidisciplinary study of Congo deep-sea fan lobe complex: Overview of methods, strategies, observations and samplingPublication . Rabouille, C.; Olu, K.; Baudin, F.; Khripounoff, A.; Dennielou, B.; ARNAUD-HAOND, Sophie; Babonneau, N.; Bayle, C.; Beckler, J.; Bessette, S.; Bombled, B.; Bourgeois, S.; Brandily, C.; Caprais, J. C.; Cathalot, C.; Charlier, K.; Corvaisier, R.; Croguennec, C.; Cruaud, P.; Decker, C.; Droz, L.; Gayet, N.; Godfroy, A.; Hourdez, S.; Le Bruchec, J.; Saout, J.; Le Saout, M.; Lesongeur, F.; Martinez, P.; Mejanelle, L.; Michalopoulos, P.; Mouchel, O.; Noel, P.; Pastor, L.; Picot, M.; Pignet, P.; Pozzato, L.; Pruski, A. M.; Rabiller, M.; Raimonet, M.; Ragueneau, O.; Reyss, J. L.; Rodier, P.; Ruesch, B.; Ruffine, L.; Savignac, F.; Senyarich, C.; Schnyder, J.; Sen, A.; Stetten, E.; Sun, Ming Yi; Taillefert, M.; Teixeira, S.; Tisnerat-Laborde, N.; Toffin, L.; Tourolle, J.; Toussaint, F.; Vetion, G.; Jouanneau, J. M.; Bez, M.The presently active region of the Congo deep-sea fan (around 330,000 km(2)), called the terminal lobes or lobe complex, covers an area of 2500 km(2) at 4700-5100 m water depth and 750-800 km offshore. It is a unique sedimentary area in the world ocean fed by a submarine canyon and a channel-levee system which presently deliver large amounts of organic carbon originating from the Congo River by turbidity currents. This particularity is due to the deep incision of the shelf by the Congo canyon, up to 30 km into the estuary, which funnels the Congo River sediments into the deep-sea. The connection between the river and the canyon is unique for major world rivers. In 2011, two cruises (WACS leg 2 and Congolobe) were conducted to simultaneously investigate the geology, organic and inorganic geochemistry, and micro- and macro-biology of the terminal lobes of the Congo deep-sea fan. Using this multidisciplinary approach, the morpho-sedimentary features of the lobes were characterized along with the origin and reactivity of organic matter, the recycling and burial of biogenic compounds, the diversity and function of bacterial and archaeal communities within the sediment, and the biodiversity and functioning of the faunal assemblages on the seafloor. Six different sites were selected for this study: Four distributed along the active channel from the lobe complex entrance to the outer rim of the sediment deposition zone, and two positioned cross-axis and at increasing distance from the active channel, thus providing a gradient in turbidite particle delivery and sediment age. This paper aims to provide the general context of this multidisciplinary study. It describes the general features of the site and the overall sampling strategy and provides the initial habitat observations to guide the other in-depth investigations presented in this special issue. Detailed bathymetry of each sampling site using 0.1-1 m resolution multibeam obtained with a remotely operated vehicle (ROV) shows progressive widening and smoothing of the channel-levees with increasing depth and reveals a complex morphology with channel bifurcations, erosional features and massive deposits. Dense ecosystems surveyed in the study area gather high density clusters of two large-sized species of symbiotic Vesicomyidae bivalves and microbial mats. These assemblages, which are rarely observed in sedimentary zones, resemble those based on chemosynthesis at cold-seep sites, such as the active pockmarks encountered along the Congo margin, and share with these sites the dominant vesicomyid species Christineconcha regab. Sedimentation rates estimated in the lobe complex range between 0.5 and 10 cm yr(-1), which is 2-3 orders of magnitude higher than values generally encountered at abyssal depths. The bathymetry, faunal assemblages and sedimentation rates make the Congo lobe complex a highly peculiar deep-sea habitat driven by high inputs of terrigenous material delivered by the Congo channel-levee system. (c) 2016 Elsevier Ltd. All rights reserved.