Éditeur(s) : HAL CCSD
Résumé : Satellite and in situ chlorophyll concentration data collected as part of VALidation HYperspectral of a BIOgeochemical model (ValHyBio), a PNTS-sponsored project dedicated to satellite ocean-colour imaging of the Southwest Pacific, are analyzed to describe chlorophyll variability in the Coral Sea, a vast oligotrophic region characterized by a deep chlorophyll maximum and blue waters of high transparency. Average chlorophyll concentrations estimated from MODIS-Aqua are very low (<0.2 mg m-3) except in the vicinity of main islands and coral reefs, where enrichment may occur due to upwelling or internal waves that bring nutrients to the euphotic zone from the deep part of the water column. During the summer season, blooms of cyanobacteria (Trichodesmium) develop in the surface waters and may form large slicks. The nitrogen fixed by these slicks is a potential source of new nitrogen later assimilated by picoplankton and the marine food chain. Coastal areas exhibit higher chlorophyll concentrations because of nutrient input from the land, as observed in 2008 around New Caledonia. In lagoon areas, the sea colour is influenced by turbidity and bathymetry, and the MODIS OC3 algorithm is inadequate, with a systematic overestimation of chlorophyll concentration in the New Caledonia lagoon. Improved bio-optical algorithms are needed for those turbid and shallow waters, to allow not only a better description of chlorophyll variability, but also evaluation of chlorophyll simulations by recently developed biogeochemical models.
of the 12th International Coral Reef Symposium, 18E
CAIRNS, Australia

hal-00746470
https://hal.archives-ouvertes.fr/hal-00746470
https://hal.archives-ouvertes.fr/hal-00746470/document

Éditeur(s) : Blackwell science
Résumé : This paper provides an exploratory analysis aiming to seek whether the colour of environmental noise theory could help in understanding the intriguing reproductive strategy of Atlantic bluefin tuna (BFT). A frequency-based approach based on spectral exponents, f(beta) with beta < 0, is chosen and applied on 10 biogeographical provinces covering the North Atlantic. The major BFT spawning area, i.e. the Mediterranean Sea, was the only one to display a pink power spectrum, whereas open ocean regions displayed more reddened fluctuations, i.e. greater variance at low frequencies. Environmental noise in the Mediterranean could, thus, offer more favourable characteristics on the long-term than the open ocean. The implications of these findings are discussed in regards to medium and long (possibly evolutionary) time scales.
Fisheries Oceanography (1054-6006) (Blackwell science), 2007-03 , Vol. 16 , N. 2 , P. 202-206

Droits : 2007 Blackwell science
http://archimer.ifremer.fr/doc/2007/publication-2437.pdf
DOI:10.1111/j.1365-2419.2006.00424.x
http://archimer.ifremer.fr/doc/00000/2437/

Éditeur(s) : HAL CCSD Cambridge University Press
Résumé : International audience
Genetic variation was examined in two complex cases of Indo-Pacific pygmy angelfishes (genus Centropyge; Pomacanthidae). The lemonpeel pygmy angelfish C. flavissima (Cuvier and Valenciennes) has a geographically disjunct Indian vs. Pacific distribution and the individuals from these two regions differ by their colour patterns. Previous research on C. flavissima has shown mitochondrial introgression from two related species, C. eibli in the eastern Indian Ocean and C. vrolikii in the Pacific Ocean. Using the 16S rDNA and the CO1 gene as phylogeographic markers, we found no mitochondrial haplotypes in common between Indian Ocean C. flavissima and C. eibli, confirming partial genetic isolation, albeit recent. Also, we found substantial genetic differences between Indian and Pacific C. flavissima populations at the nuclear ETS-2 intron locus. The Indian Ocean form of C. flavissima, thus geographically isolated by >2000 km distance from its Pacific Ocean counterpart, is described as a new species, Centropyge cocosensis sp. nov. Centropyge cocosensis sp. nov. differs in appearance from C. flavissima in having a conspicuous blue iris and a fainter, bluish eye ring. We also found that the yellow pygmy angelfish C. heraldi Woods and Schultz consists of two genetically distinct entities, one distributed widely in the northern tropical Indo-West Pacific, the other distributed in the southern Pacific Ocean. The name originally given to the blackfin pygmy angelfish, C. woodheadi Kuiter, is here resurrected to designate the latter.
EISSN: 1755-2672

hal-01340521
https://hal-univ-perp.archives-ouvertes.fr/hal-01340521
DOI : 10.1007/s12526-016-0509-y

Éditeur(s) : Université Paul Sabatier, Toulouse III
Résumé : The marine phytoplankton in the ocean represents only less than 1% of global biomass. Phytoplankton performs half of all photosynthesis. This autotrophic biomass in ocean is then an essential element in the climate regulation through processes as carbon dioxide absorption during the photosynthesis. Therefore, we need to estimate precisely this biomass as well as the processes which affect it. Using remotely sensed data (altimetry and ocean colour) and a coupled physical/biogeochemical model (MERCATOR-OPA/NPZDDON), Rossby waves and their influence on phytoplankton biomass are specifically studied in the North Atlantic Ocean. Their features and their influences on surface chlorophyll concentrations were analysed. Through the different mechanisms identified, we estimated that these waves can induce local increases from 60% to 150% of the estimated primary production.
Même si l'océan ne représente que moins de 1% de la biomasse liée aux plantes sur la terre, il est responsable de près de la moitié de la photosynthèse nette de la biosphère. Cette biomasse est par conséquent un élément essentiel dans la régulation du climat à travers par exemple le cycle océanique du carbone. Il est donc nécessaire d'estimer correctement cette biomasse ainsi que les processus qui l'affectent. A l'aide de données satellites altimétriques et couleur de l'eau et d'un modèle couplé physique/biogéochimie (MERCATOR-OPA / NPZDDON), les ondes de Rossby et leur influence sur cette biomasse sont spécifiquement étudiées dans l'océan Atlantique Nord. Leurs propriétés et leur influence sur les concentrations en chlorophylle de surface sont analysées. Au travers des mécanismes mis en jeu identifiés, nous estimons que ces ondes peuvent entraîner une augmentation locale comprise entre 60% et 150% de la production primaire estimée.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2005/these-2454.pdf
http://archimer.ifremer.fr/doc/00000/2454/

Éditeur(s) : Société Française d'Ichtyologie
Résumé : In the present paper a new genus, Diretmoides, and a new species, Diretmoides parini, of the berycomorph family Diretmidae is described. The hitherto single genus of the family, Diretmus Johnson, 1863, therefore becomes monotypic while the new genus includes two species pauciradiatus (Woods, 1973) and parini sp. nov. The genus Diretmus is mainly charactcrized by three features (1) by its anus placed immediately anterior to the anal fin, (2) by a prepelvic ridge of ventral scutes and (3) by the high number of bony lamellae on the upper third of the operculum. The species of Diretmoides on the other hand have (1) their anus midway between the pelvics and the anal fin, (2) the ventral midline anterior to their pelvics is flat and is covered by normal body-scales and (3) there are only a few lamellae on the upper third of the operculum. Juveniles of the two Diretmoides-species differ from each other in their colour pattern,the adolescents and adults in meristic characters. All described species live meso-to bathypelagically. D. argenteus is widely distributed in tropical and temperate waters of all oceans. The two Diretmoides -species also live in the Atlantic as well as in the Pacific. However there is only one record of Diretmoides parini and none of D. pauciradiatus from the Indian Ocean. In addition to the described species, indication is given of the presumable existence of a third Diretmoides-species from off Japan. Artificial keys to adults and juveniJes are given at the end of this paper. NOT CONTROLLED OCR
Les auteurs décrivent un nouveau genre, Diretmoides, et une nouvelle espèce, Diretmoides parini. Le genre Diretmus ne comprend plus qu'une seule espèce D. argenteus Johnson, 1863; Diretmoides en comporte deux;D. pauciradiatus (Woods, 1973) d D. parini n.sp. Le genre Diretmus est caractérisé principalement par la position de l'anus juste en avant de l'anale par la présence en avant des pelviennes d'une carène épineuse ventrale et par la densité des lamelles osseuses sur le tiers supérieur de l'opercule. Chez Diretmoides l'anus est à mi-distance entre l'anale et les pelviennes; il n'y a pas de carène épineuse ventrale en avant des pelviennes et, sur le tiers supérieur de l'opercule, les lamelles osseuses sont peu nombreuses et éparses. Les jeunes Diretmoides se distinguent les uns des autres par leur coloration, les adolescents et les adultes par leurs caractères méristiques. Tous les Diretmidés actuellement connus sont des espèces méso à bathypélagiques. D. argenteus est largement distribué dans les eaux tropicales et tempérées de tous les océans. Les deux espèces de Diretmoides ont été signalées dans l'Atlantique et te Pacifique mais on ne connaît qu'une seule capture de D. parini dans l'océan indien et aucune de D. pauciradiatus. En outre. l'étude d'exemplaires provenant du Japon a amené les auteurs à souligner l'existence probable d'une troisième espèce de Diretmoides. Deux clés de détermination, l'une pour les adultes, l'autre pour les jeunes des trois espèces décrites, sont données à la fin de cette note. OCR NON CONTRÔLE
Cybium (Société Française d'Ichtyologie), 1981 , Vol. 5 , N. 1 , P. 33-60

Droits : 1981 Société Française d'Ichtyologie
http://archimer.ifremer.fr/doc/1981/publication-3746.pdf
http://archimer.ifremer.fr/doc/00000/3746/

Éditeur(s) : Wiley-blackwell Publishing, Inc
Résumé : Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting for temperature and ecological factors such as ecosystem size and type, species richness, animal body size, and the degree and nature of fisheries exploitation. Indeed we show that global fisheries catches since 1950 have been increasingly constrained by the amount of primary production. The primary production appropriated by current global fisheries is 17-112% higher than that appropriated by sustainable fisheries. Global primary production appears to be declining, in some part due to climate variability and change, with consequences for the near future fisheries catches.
Ecology Letters (1461-023X) (Wiley-blackwell Publishing, Inc), 2010-04 , Vol. 13 , N. 4 , P. 495-505

Droits : 2010 Blackwell Publishing Ltd/CNRS
http://archimer.ifremer.fr/doc/00002/11294/7836.pdf
DOI:10.1111/j.1461-0248.2010.01443.x
http://archimer.ifremer.fr/doc/00002/11294/

Éditeur(s) : Gauthier-Villars
Résumé : In the sedimentary areas surrounding the Florida Keys, Soritidae and Peneroplidae are very well represented. These benthic foraminifera are generally attached to seagrasses or algae and more rarely to carbonate deposits. The colouring of their protoplasm results from the nature of endosymbiotic algae. The principal species represented are: Androsina lucasi (never recorded before in Florida) which lives only in the margino-littoral biotopes where the salinity is highly variable; Archaias angulatus and Amphisorus hemprichii which live in the biotopes of the littoral platform but also in those of the interior margin of the bay where the variations of salinity are weak; Cyclorbiculina compressa and Peneroplis proteus which live for the main part in the littoral biotopes of the oceanic platform where the salinity is normal and quite constant; five other species of secondary importance take the number of taxa observed alive in the Keys area up to ten. Moreover, if the comparison of the biocenoses and thanatocenoses emphasizes their comparative similitude, knowledge of the biocenoses permits a better understanding of their adaptation to present-day environments.
Oceanologica Acta (0399-1784) (Gauthier-Villars), 1991 , Vol. 14 , N. 5 , P. 515-524

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00103/21379/18979.pdf
http://archimer.ifremer.fr/doc/00103/21379/