Search

This study reports the occurrence of the oceanic basslet (Howellidae) in Brazilian waters. Bathysphyraenops simplex Parr, 1933, a rare species with a worldwide distribution, is recorded for the first time in Brazilian waters, based on three specimens collected off Rocas Atoll and Rio Grande do Norte. Howella atlantica Post & Quéro, 1991, known from the western and eastern Atlantic Ocean (64°N to 21°S), including waters around the Trindade Island, is reported off Rio Grande do Norte, Pernambuco, Rocas Atoll, and the Fernando de Noronha Archipelago. In addition, specimens previously reported in the literature as Howella brodie Ogilby, 1899 are reidentified as H. atlantica, extending the known distribution of this species to northeastern and southeastern Brazil. Measurements and counts for all specimens examined are provided.

A variety of gravel- to cobble-sized rocks, recovered from the Mar del Plata (MdP) Canyon area (Western South Atlantic at 38°S) and interpreted as ice-rafted debris, represent the first evidence that large icebergs have floated in the Falkland (Malvinas) Current from the southern polar high latitudes far northward. Detailed petrographic analyses identified the Antarctic Peninsula, sub-Antarctic islands in the Scotia Sea, and Tierra del Fuego as plausible source areas. The drift process could have started as early as at the beginning of the last deglaciation, according to an age obtained from a cold-water coral fragment associated with one of the dropstones. At the end of the Last Glacial Maximum, large icebergs have been supplied to the Antarctic Circumpolar Current, captured by those ocean current branches that circumvent the Falkland (Malvinas) Islands and entered the Argentine Margin. When the iceberg fleets approached the Brazil-Falkland (Malvinas) Confluence Zone with its steep latitudinal temperature gradient, the icebergs got oceanographically trapped and melted off rapidly. The sediment load sinking down to the seafloor formed a dropstone blanket particularly where the MdP Canyon had incised into the continental slope. Here, mass-flow processes, induced by local slope instability, and along-slope sediment resorting, due to the erosional effects of strong and persistent contouritic bottom currents, favored local enrichment in dropstones in the form of a loose, coarse sediment drape inside morphological depressions. The bottom current velocity would be locally strong enough to rework this sediment, leaving coarse rafted debris as a lag deposit. Fil: Bozzano, Graziella. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Cerredo, Maria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Remesal, Marcela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Steinmann, L.. Universitat Bremen; Alemania Fil: Hanebuth, Till J.J.. Coastal Carolina University; Estados Unidos Fil: Schwenk, T.. Universitat Bremen; Alemania Fil: Baqués, Michele. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Ministerio de Defensa. Armada Argentina. Dirección Gral. de Investigación y Desarrollo de la Ara. Dirección de Investigación de la Armada; Argentina Fil: Hebbeln, Dierk. Universitat Bremen; Alemania Fil: Spoltore, Daniela Veronica. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Silvestri, Ornella. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Universidad de Buenos Aires; Argentina Fil: Acevedo, Rogelio Daniel. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Ambientales y Recursos Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina Fil: Spiess, V.. Universitat Bremen; Alemania Fil: Violante, Roberto Antonio. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina Fil: Kasten, Sabine. Universitat Bremen; Alemania. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research; Alemania

The Serra Spanish Mackerel, Scomberomorus brasiliensis is one of the principal fishery resources found in the tropical and subtropical waters of the western South Atlantic. Declining catches of S. brasiliensis off the coast of northeastern Brazil indicate that this species is being overfished. Despite the importance of this species to local fisheries, few data are available on its genetic diversity or population parameters. Given this scenario, the present study evaluated the genetic variability of S. brasiliensis off the coast of the western South Atlantic, based on mitochondrial genes. We compiled two databases, one with partial sequences of the MT-CYB gene (N = 105), and the other of the MT-ND4 gene of the Serra Spanish Mackerel, sampled from eight localities, ranging from Cumana in Venezuela to Paranaguá, in southern Brazil. The results of the analysis indicate low levels of genetic diversity in the study. Samples from Cumana, on the coast of Venezuela were the most differentiated, although the results of the AMOVA were not significant. The PhiST values, the genetic divergence, and the haplotype network all indicate the widespread sharing of haplotypes by the mackerel from all the different localities. Analyses of the historical demography, based on both markers, indicate the occurrence of past population expansion, coinciding with fluctuations in sea level that occurred 10,000 years ago. The demographic and phylogeographic analyses of the mitochondrial DNA revealed the existence of a single genetic stock of S. brasiliensis on the coast of the western South Atlantic according to. These findings are fundamental to the development of effective conservation strategies.

International audience; Cobalt (Co) and iron (Fe) are essential for phytoplankton nutrition, and as such constitute a vital link in the marine biological carbon pump. Atmospheric deposition is an important, and in some places the dominant, source of trace elements (TEs) to the global ocean. Dissolved cobalt (dCo) and iron (dFe) were determined along an Atlantic Meridional Transect (AMT-19; Oct/Nov 2009) between 50°N and 40°S in the upper 150 m in order to investigate the behaviour and distribution of these two essential, bioactive TEs. During AMT-19, large differences in the distributions of dCo and dFe were observed. In the North Atlantic gyre provinces, extremely low mixed layer dCo concentrations (23 ± 9 pM) were observed, which contrasts with the relatively high mixed layer dFe concentrations (up to 1.0 nM) coincident with the band of highest atmospheric deposition (∼5–30°N). In the South Atlantic gyre, the opposite trend was observed, with relatively high dCo (55 ± 18 pM) observed throughout the water column, but low dFe concentrations (0.29 ± 0.08 nM). Given that annual dust supply is an order of magnitude greater in the North than the South Atlantic, the dCo distribution was somewhat unexpected. However, the distribution of dCo shows similarities with the distribution of phosphate (PO43−) in the euphotic zone of the Atlantic Ocean, where the North Atlantic gyre is characterised by chronically low PO4, and higher concentrations are observed in the South Atlantic gyre (Mather et al., 2008), suggesting the potential for a similar biological control of dCo distributions. Inverse correlations between dCo and Prochlorococcus abundance in the North Atlantic gyre provinces, combined with extremely low dCo where nitrogen fixation rates were highest (∼20–28°N), suggests the dominance of biological controls on dCo distributions. The contrasting dCo and dFe distributions in the North and South Atlantic gyres provides insights into the differences between the dominant controls on the distribution of these two bioactive trace metals in the central Atlantic Ocean.

We provide a new multivariate calibration-function based on South Atlantic modern assemblages of planktonic foraminifera and atlas water column parameters from the Antarctic Circumpolar Current to the Subtropical Gyre and tropical warm waters (i.e., 60°S to 0°S). Therefore, we used a dataset with the abundance pattern of 35 taxonomic groups of planktonic foraminifera in 141 surface sediment samples. Five factors were taken into consideration for the analysis, which account for 93% of the total variance of the original data representing the regional main oceanographic fronts. The new calibration-function F141-35-5 enables the reconstruction of Late Quaternary summer and winter sea-surface temperatures with a statistical error of ~ 0.5°C. Our function was verified by its application to a sediment core extracted from the western South Atlantic. The downcore reconstruction shows negative anomalies in sea-surface temperatures during the early–mid Holocene and temperatures within the range of modern values during the late Holocene. This pattern is consistent with available reconstructions. Fil: García Chapori, Natalia Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos; Argentina Fil: Mazur Chiessi, Cristiano. Universidade de Sao Paulo; Brasil Fil: Bickert, Torsten. Universitat Bremen; Alemania Fil: Laprida, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos; Argentina

A variação no padrão das placas de dentes vômero-palatinas de Genidens barbus e Genidens machadoi é revista e as espécies redescritas com base na análise de 46 caracteres morfológicos. Genidens machadoi pode ser diferenciada de Genidens barbus pela: margem lateral do esfenótico recortada (vs. margem lateral do esfenótico retilínea); escudo cefálico mais estreito na região dos esfenóticos (vs. escudo cefálico mais estreito na região dos frontais); distância entre a margem lateral do escudo cefálico, na porção mais estreita, e a margem posterior da órbita cabendo 0,681,0 na menor largura do escudo cefálico (vs. 1,21,7); menor largura do processo occipital, na porção posterior, cabendo 2,03,4 no comprimento do processo occipital (vs. 3,34,7); um ou dois pares de placas de dentes na região do palato, par anterior arredondado e pequeno, par posterior ovalado às vezes confluente ou fusionado com o par anterior (vs. placas de dentes na região do palato formando um conjunto com aspecto de uma ferradura, as placas totalmente fusionadas ou confluentes e distintas, mas sempre com uma projeção posterior); maior comprimento das placas de dentes cabendo 3,24,9 na altura da cabeça (vs. 1,93,4); granulação no escudo cefálico espessa e irregularmente distribuída (vs. fina e distribuída em série regulares).Variation in the pattern of the vomero-palatine tooth patches of Genidens barbus and Genidens machadoi is reviewed and the species redescribed based on the analysis of 46 morphological characters. Genidens machadoi can be distinguished from Genidens barbus by: the notched lateral margin of the sphenotic (vs. lateral margin of the sphenotic straight); the cephalic shield narrowest in the sphenotic (vs. cephalic shield narrowest in the frontal); distance between the lateral margin of the cephalic shield, at narrowest portion, and the posterior margin of the orbit 0.681.0 of the smallest width of the cephalic shield (vs. 1.21.7); width of the posterior extremity of the supra-occipital process 2.03.4 of the length of the supra-occipital process (vs. 3.34.7); one or two groups of tooth patches on roof of mouth, anterior patch small and round, posterior patch oval, sometimes confluent or fused with the front group (vs. patches a with horseshoe shape, patches totally fused or divided in confluent groups, always with a posterior projection); longest length of the tooth patches 3.24.9 of the height of the head (vs. 1.93.4); granulation on cephalic shield coarse and irregularly distributed (vs. smooth and distributed in regular series).