Consulta: subjectFacets:"South Atlantic"
Registros recuperados: 38
Data/hora: 09/06/2024 06:24:12

Lagrangian circulation of Antarctic Intermediate Water in the subtropical South Atlantic
Provedor de dados: 5
Autores: Nunez Riboni, Ismael; Boebel, Olaf; Ollitrault, Michel; You, Yuzhu; Richardson, Philip; Davis, Russ.
This study combines float data from different projects collected between 1991 and 2003 in the South Atlantic to describe the flow of Antarctic Intermediate Water (AAIW). Velocity space-time averages are calculated for various grid resolutions and with cells deformed to match the bathymetry, f/H or f/h (with H being the water depth and It being the thickness of the AAIW layer). When judged by the degree of alignment between respective isolines and the resulting average velocity fields, the best grid is based on a nominal cell size of 3&amp;DEG; (latitude) by 4&amp;DEG; (longitude) with cell shapes deformed according to f/h. Using this grid, objectively estimated mean currents (and their associated errors), as well as meridional and zonal volume transports...
Tipo: Text
Palavras-chave: Objective analysis; Transports; Lagrangian circulation; South Atlantic; Neutral density surfaces; Floats; Antarctic Intermediate Water ( AAIW ).
Ano: 2005
URL: https://archimer.ifremer.fr/doc/2005/publication-781.pdf

Width variation around submarine channel bends: Implications for sedimentation and channel evolution
Provedor de dados: 5
Autores: Palm, Franziska A.; Peakall, Jeff; Hodgson, David M.; Marsset, Tania; Silva Jacinto, Ricardo; Dennielou, Bernard; Babonneau, Nathalie; Wright, Tim J.
Submarine-fan channels can build the largest sediment accumulations on Earth, but our understanding of flow and sedimentation processes related to channel evolution remains limited. Results from physical and numerical modelling predict dominantly downstream channel bend migration. However, observations and evolutionary models for aggradational submarine channels on passive margins suggest that bends are dominated by lateral expansion. This paradox may be due to limitations induced by the use of constant width channels in process studies. Constant width has been used for two reasons: partly because this is the simplest possible case, but primarily because the width variation around submarine channel bends is unknown. Channel width variations are examined...
Tipo: Text
Palavras-chave: Submarine channel; Congo; Channel morphology; Sedimentation; Bank pull; Quaternary; Monsoon; South Atlantic.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00693/80473/83602.pdf

Diurnal Variability of Persistent Organic Pollutants in the Atmosphere over the Remote Southern Atlantic Ocean
Provedor de dados: 5
Autores: Gioia, Rosalinda; Macleod, Matthew; Castro-jimenez, Javier; Nizzetto, Luca; Dachs, Jordi; Lohmann, Rainer; Jones, Kevin C.
A diel (24-h) cycle with daytime atmospheric concentrations higher than nighttime concentrations by a factor of 1.5-3 was observed for several low molecular weight polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in remote areas of the tropical South Atlantic during a cruise in October-November 2005. In contrast, high molecular weight PCBs and PAHs did not display diurnal variability. A model which has successfully explained diel variability of persistent organic pollutants (POPs) over land could not reproduce the observed diel cycle by considering variability in temperature, atmospheric OH radical concentrations, atmospheric boundary layer height and wind speed as causal factors. We used the model to conduct two bounding...
Tipo: Text
Palavras-chave: Persistent organic pollutants (POPs); Diurnal cycle; Polychlorinated biphenyls (PCBs); Polycyclic aromatic hydrocarbons (PAHs); South Atlantic.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00645/75721/76676.pdf

Upper-layer circulation in the eastern Equatorial and South Atlantic Ocean in January-March 1995
Provedor de dados: 5
Autores: Mercier, Herle; Arhan, Michel; Lutjeharms, Johann.
The upper-layer circulation in the eastern basin of the South Atlantic was studied from hydrographic and direct velocity measurements along WOCE lines A11, A13 and A14. A13 and A14 provide quasi-meridional samplings of the equatorial, subequatorial and subtropical circulation regimes. A13 was carried out along the African coast at about 600 km offshore from it, and A 14 along the nominal longitude 9degreesW. A11 intersects the Cape Basin between 46degreesS in the west and 30degreesS in the east. Transport estimates were derived from direct velocity measurements and a box inverse model. In the equatorial eastern Atlantic, the Equatorial Undercurrent (EUC) transport decreases from 25x10(6) m(3) s(-1) at 9degreesW to 13x10(6) m(3) s(-1) at 5degreesE....
Tipo: Text
Palavras-chave: Hydrography; Current; Circulation; South Atlantic; Equatorial Atlantic.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/2003/publication-460.pdf

Basin-Wide Oceanographic Array Bridges the South Atlantic
Provedor de dados: 5
Autores: Ansorge, Isabelle J.; Baringer, Molly; Campos, Edmo J.d.; Dong, S.; Fine, R.a.; Garzoli, Silvia L.; Goni, Gustavo; Meinen, Christopher S.; Perez, R.c.; Piola, Alberto R.; Roberts, M.j.; Speich, Sabrina; Sprintall, J.; Terre Terrillon, Thierry; Van Den Berg, M.a.
The meridional overturning circulation (MOC) is a global system of surface, intermediate, and deep ocean currents. The MOC connects the surface layer of the ocean and the atmosphere with the huge reservoir of the deep sea and is the primary mechanism for transporting heat, freshwater, and carbon between ocean basins. Climate models show that past changes in the strength of the MOC were linked to historical climate variations. Further research suggests that the MOC will continue to modulate climate change scenarios on time scales ranging from decades to centuries [Latif et al., 2006].
Tipo: Text
Palavras-chave: South Atlantic; Meridional Overturning Circulation; CPIES.
Ano: 2014
URL: http://archimer.ifremer.fr/doc/00175/28609/27109.pdf

Circulation de bord ouest de l'Atlantique Sud: analyse d'observations lagrangiennes et hydrologiques
Provedor de dados: 5
Autores: Legeais, Jean-francois.
The "World Ocean Circulation experiment" (WOCE) program in the 1990s has produced the equivalent of 300 years of subsurface floats trajectories within the Antarctic Intermediate Water (AAIW) at 800dbar in the South Atlantic ocean, and several hydrological transects. In order to compute the western boundary circulation, the flow is vertically extrapolated by referencing geostrophic hydrological profiles to float speeds. Several transects normal to the continental slope and another one parallel to it off the coast give transports of the water masses with a good transversal and longitudinal resolutions. Floats at 800dbar sampled the Intermediate Western Boundary Current (IWBC) particularly well, and enable one to analyse it from 28°S at the bifurcation of the...
Tipo: Text
Palavras-chave: Mesoscale activity; Bathymetry; Hydrological transect; IWBC; AAIW; Western boundary; South Atlantic; Lagrangian floats; Activité de méso échelle; Bathymétrie; Radiale hydrologique; IWBC; AAIW; Bord ouest; Atlantique Sud; Flotteur lagrangien.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-6177.pdf

Evolution of South Atlantic density and chemical stratification across the last deglaciation
Provedor de dados: 5
Autores: Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C.; Peck, Victoria L.; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Riveiros, Natalia Vazquez; Hodell, David A.
Explanations of the glacial-interglacial variations in atmospheric pCO(2) invoke a significant role for the deep ocean in the storage of CO2. Deep-ocean density stratification has been proposed as a mechanism to promote the storage of CO2 in the deep ocean during glacial times. A wealth of proxy data supports the presence of a "chemical divide" between intermediate and deep water in the glacial Atlantic Ocean, which indirectly points to an increase in deep-ocean density stratification. However, direct observational evidence of changes in the primary controls of ocean density stratification, i.e., temperature and salinity, remain scarce. Here, we use Mg/Ca-derived seawater temperature and salinity estimates determined from temperature-corrected delta O-18...
Tipo: Text
Palavras-chave: South Atlantic; Density gradient; Ocean stratification; Last deglaciation; Atmospheric CO2.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00421/53276/54569.pdf

Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years
Provedor de dados: 5
Autores: Howe, Jacob N. W.; Piotrowski, Alexander M.; Oppo, Delia W.; Huang, Kuo-fang; Mulitza, Stefan; Chiessi, Cristiano M.; Blusztajn, Jurek.
Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd...
Tipo: Text
Palavras-chave: Antarctic Intermediate Water; Neodymium isotopes; Degalciation; South Atlantic.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00421/53216/54848.pdf

Carbon and silica megasink in deep-sea sediments of the Congo terminal lobes
Provedor de dados: 5
Autores: Rabouille, C.; Dennielou, Bernard; Baudin, F.; Raimonet, M.; Droz, Laurence; Khripounoff, Alexis; Martinez, P.; Mejanelle, L.; Michalopoulos, P.; Pastor, Lucie; Pruski, A.; Ragueneau, Olivier; Reyss, J.-l.; Ruffine, Livio; Schnyder, J.; Stetten, E.; Taillefert, M.; Tourolle, Julie; Olu, Karine.
Carbon and silicon cycles at the Earth surface are linked to long-term variations of atmospheric CO2 and oceanic primary production. In these cycles, the river-sea interface is considered a biogeochemical hotspot, and deltas presently receive and preserve a major fraction of riverine particles in shallow water sediments. In contrast, periods of glacial maximum lowstand were characterized by massive exports of sediments to the deep-sea via submarine canyons and accumulation in deep-sea fans. Here, we calculate present-day mass balances for organic carbon (OC) and amorphous silica (aSi) in the terminal lobe complex of the Congo River deep-sea fan as an analogue for glacial periods. We show that this lobe complex constitutes a megasink with the current...
Tipo: Text
Palavras-chave: Present; Paleoceanography; South Atlantic; Inorganic geochemistry; Organic geochemistry; Sedimentology-marine cores.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00511/62289/66720.pdf

Iron isotopes reveal distinct dissolved iron sources and pathways in the intermediate versus deep Southern Ocean
Provedor de dados: 5
Autores: Abadie, Cyril; Lacan, Francois; Radic, Amandine; Pradoux, Catherine; Poitrasson, Franck.
As an essential micronutrient, iron plays a key role in oceanic biogeochemistry. It is therefore linked to the global carbon cycle and climate. Here, we report a dissolved iron (DFe) isotope section in the South Atlantic and Southern Ocean. Throughout the section, a striking DFe isotope minimum (light iron) is observed at intermediate depths (200–1,300 m), contrasting with heavier isotopic composition in deep waters. This unambiguously demonstrates distinct DFe sources and processes dominating the iron cycle in the intermediate and deep layers, a feature impossible to see with only iron concentration data largely used thus far in chemical oceanography. At intermediate depths, the data suggest that the dominant DFe sources are linked to organic matter...
Tipo: Text
Palavras-chave: Iron isotopes; GEOTRACES; South Atlantic; Southern Ocean; Remineralization.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00367/47864/47859.pdf

Nutrient mineralization rates and ratios in the eastern South Atlantic - art. no. C05030
Provedor de dados: 5
Autores: Brea, Samenta; Alvarez Salgado, X; Alvarez, M; Perez, F; Memery, L; Mercier, Herle; Messias, M.j.
The physical and biogeochemical components of nutrients and inorganic carbon distributions along WOCE line A14 are objectively separated by means of a constrained least-squares regression analysis of the mixing of eastern South Atlantic water masses. Contrary to previous approaches, essentially devoted to the intricate South Atlantic circulation, this work is focused on the effects of circulation on nutrients and carbon biogeochemistry, with special emphasis on the stoichiometry and the rate of mineralization processes. Combination of nutrient and apparent CFC-age anomalies, derived from the mixing analysis, indicate faster mineralization rates in the equatorial (12 x 10(-2) mumol P kg(-1) yr(-1)) and subequatorial (5.3 x 10(-2) mumol P kg(-1) yr(-1)) than...
Tipo: Text
Palavras-chave: South Atlantic; Biogeochemical cycles; Water masses.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/2004/publication-836.pdf

High precision U-series dating of scleractinian cold-water corals using an automated chromatographic U and Th extraction
Provedor de dados: 5
Autores: Wefing, Anne-marie; Arps, Jennifer; Blaser, Patrick; Wienberg, Claudia; Hebbeln, Dierk; Frank, Norbert.
High-precision U-series dating of scleractinian cold-water corals is a key chronological tool for studies of past environmental and climate conditions. Here, we tested and optimized an automated chemical extraction system (ESI prepFAST-MC equipped with an Eichrom TRU-resin chromatographic column) for its ability to purify U and Th isotopes for mass spectrometric U-series dating at the sub-‰ precision level. Chemical yields are constantly high, on average around 90% for both U and Th. Analytical blanks are comparable to manual purification (&lt; 0.15 pg U, 0.15 pg Th for a typical sample of 50 mg) and memory effects due to the recycling of the column are mostly insignificant as the carry-over fraction is about 10− 5 for Th and 10− 3 for U isotopes. However,...
Tipo: Text
Palavras-chave: U-series dating; PrepFAST-MC; Cold-water corals; South Atlantic; Angola; Past climate.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00409/52058/52761.pdf

Meridional Overturning Circulation Transport Variability at 34.5 degrees S During 2009-2017: Baroclinic and Barotropic Flows and the Dueling Influence of the Boundaries
Provedor de dados: 5
Autores: Meinen, Christopher S.; Speich, Sabrina; Piola, Alberto R.; Ansorge, Isabelle; Campos, Edmo; Kersale, Marion; Terre Terrillon, Thierry; Chidichimo, Maria Paz; Lamont, Tarron; Sato, Olga T.; Perez, Renellys C.; Valla, Daniel; Van Den Berg, Marcel; Le Henaff, Matthieu; Dong, Shenfu; Garzoli, Silvia L.
Six years of simultaneous moored observations near the western and eastern boundaries of the South Atlantic are combined with satellite winds to produce a daily time series of the basin-wide meridional overturning circulation (MOC) volume transport at 34.5 degrees S. The results demonstrate that barotropic and baroclinic signals at both boundaries cause significant transport variations, and as such must be concurrently observed. The data, spanning similar to 20 months during 2009-2010 and similar to 4 years during 2013-2017, reveal a highly energetic MOC record with a temporal standard deviation of 8.3 Sv, and strong variations at time scales ranging from a few days to years (peak-to-peak range = 54.6 Sv). Seasonal transport variations are found to have...
Tipo: Text
Palavras-chave: Meridional overturning circulation; South Atlantic; Overturning; Volume transport; Observations.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00445/55612/57253.pdf

Increased input of circumpolar deep water-borne detritus to the glacial SE Atlantic Ocean
Provedor de dados: 5
Autores: Bayon, Germain; German, Cr; Nesbitt, Rw; Bertrand, P; Schneider, Rr.
[1] Analysis of radiogenic isotopes in marine sediments can provide useful information on the provenance and transport of detrital material, directly relevant to paleoceanographic investigations. Here we show that the detrital Nd isotopic composition of recent SE Atlantic marine sediments matches the complex modern-day hydrography. In these same cores, glacial-interglacial isotopic variations are consistent with previous investigations (using different paleoceanographic proxies), which have shown that the relative influence of North Atlantic Deep Water (NADW) into the South Atlantic was reduced during glacial periods. In a novel departure, however, we also calculate the mass accumulation rates of terrigenous material delivered by each of Circumpolar Deep...
Tipo: Text
Palavras-chave: Neodymium isotopes; Detrital fractions; South Atlantic; Deep water circulation; IMAGES; Marine geology and geophysics : marine sediments processes and transport; Oceanography : general : paleoceanography.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00000/10190/9912.pdf

Ocean circulation and climate variability in the western South Atlantic and eastern South America during the last deglaciation
Provedor de dados: 5
Autores: Chiessi, Cristiano Mazur.
The growing impact of human activities on the climate system adds a new dimension of complexity and urgency to climate change research. Human activities may have the potential to push key components of the climate system past critical states into qualitatively different modes of operation, i.e. to exceed a tipping point. This possibility requires additional efforts from the many branches of climate change research in order to improve the accuracy of climate change projections. The examination of past climate records has proven to be a very useful area of climate change research. This thesis tackles two elements of the climate system whose tipping points are currently considered very critical: the Atlantic meridional overturning circulation and South...
Tipo: Text
Palavras-chave: South Atlantic; South America; Last deglaciation; Stable isotopes; Trace elements; Atlantic meridional overturning circulation; South American summer monsoon.
Ano: 2008
URL: https://archimer.ifremer.fr/doc/00495/60660/64157.pdf

A glacial warm water anomaly in the subantarctic Atlantic Ocean, near the Agulhas Retroflection
Provedor de dados: 5
Autores: Cortese, G; Abelmann, A; Gersonde, R.
ODP Site 1089 is optimally located in order to monitor the occurrence of maxima in Agulhas heat and salt spillage from the Indian to the Atlantic Ocean. Radiolarian-based paleotemperature transfer functions allowed to reconstruct the climatic history for the last 450 kyr at this location. A warm sea surface temperature anomaly during Marine Isotope Stage (MIS) 10 was recognized and traced to other oceanic records along the surface branch of the global thermolialine (THC) circulation system, and is particularly marked at locations where a strong interaction between oceanic and atmospheric overturning cells and fronts occurs. This anomaly is absent in the Vostok ice core deuterium, and in oceanic records from the Antarctic Zone. However, it is present in the...
Tipo: Text
Palavras-chave: Agulhas; Paleotemperature; Radiolarians; South Atlantic.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00229/34028/32422.pdf

Temporal variability of the meridional overturning circulation at 34.5°S: Results from two pilot boundary arrays in the South Atlantic
Provedor de dados: 5
Autores: Meinen, Christopher S.; Speich, Sabrina; Perez, Renellys C.; Dong, Shenfu; Piola, Alberto R.; Garzoli, Silvia L.; Gladyshev, Sergey; Baringer, Molly; Campos, Edmo J. D.
Data from two boundary arrays deployed along 34.5°S are combined to produce the first continuous in situ time series observations of the basin-wide meridional overturning circulation (MOC) in the South Atlantic. Daily estimates of the MOC between March 2009 and December 2010 range between 3 Sv and 39 Sv (1 Sv = 106 m3 s−1) after a 10 day low-pass filter is applied. Much of the variability in this ∼20 month record occurs at periods shorter than 100 days. Approximately two-thirds of the MOC variability is due to changes in the geostrophic (baroclinic plus barotropic) volume transport, with the remainder associated with the direct wind-forced Ekman transport. When low-pass filtered to match previously published analyses in the North Atlantic, the observed...
Tipo: Text
Palavras-chave: Meridional overturning circulation; Transport; South Atlantic; Inverted echo sounder; Bottom pressure.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00167/27789/25982.pdf

Contribution of seasonal sub-Antarctic surface water variability to millennial-scale changes in atmospheric CO2 over the last deglaciation and Marine Isotope Stage 3
Provedor de dados: 5
Autores: Gottschalk, Julia; Skinner, Luke C.; Waelbroeck, Claire.
The Southern Ocean is thought to have played a key role in past atmospheric carbon dioxide (CO2,(atm)) changes. Three main factors are understood to control the Southern Ocean's influence on CO2,(atm), via their impact on surface ocean pCO(2) and therefore regional ocean-atmosphere CO2 fluxes: 1) the efficiency of air-sea gas exchange, which may be attenuated by seasonal- or annual sea-ice coverage or the development of a shallow pycnocline; 2) the supply of CO2-rich water masses from the subsurface and the deep ocean, which is associated with turbulent mixing and surface buoyancy- and/or wind forcing; and 3) biological carbon fixation, which depends on nutrient availability and is therefore influenced by dust deposition and/or upwelling. In order to...
Tipo: Text
Palavras-chave: South Atlantic; Planktonic foraminifera; Stable oxygen and carbon isotopes; Atmospheric CO2; Last glacial period.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00297/40868/39920.pdf

Marine zooplanktonic diversity: a view from the South Atlantic
Provedor de dados: 5
Autores: Boltovskoy, D; Correa, N; Boltovskoy, A.
Approximately 7000 marine zooplanktonic species have been described so far for the World Ocean; in the South Atlantic the presence of 40% of these has been confirmed, and an additional 20-30% are expected to be recorded in the future. The overall number of described species is very low when compared with other communities, and yet it may not be too far from the final, complete inventory. Very ample geographic distributional ranges, compositional similarity between the major oceanic basins, and declining species description rates suggest that the undescribed fraction of marine zooplankton is nowhere as large as those suggested for the biosphere as a whole. It is anticipated that the highest proportions of new species will be among the groups associated....
Tipo: Text
Palavras-chave: Zooplancton; Diversité; Atlantique Sud; Zooplancton; Diversity; South Atlantic.
Ano: 2002
URL: http://archimer.ifremer.fr/doc/00322/43310/42964.pdf

Planktonic foraminiferal sea surface temperature variations in the southeast Atlantic Ocean: A high-resolution record MD962085 of the past 400,000 years from the IMAGES II-NAUSICAA cruise
Provedor de dados: 5
Autores: Chang, Yp; Chang, Cc; Wang, Lw; Chen, Mt; Wang, Ch; Yu, Ef.
A high-resolution (similar to 4 - 5cm/kyr) giant piston core record (MD962085) retrieved during an IMAGES II - NAUSICAA cruise from the continental slope of the southeast Atlantic Ocean reveal striking variations in planktonic foraminifer faunal abundances and sea-surface temperatures (SST) during the past 400,000 years. The location and high-quality sedimentary record of the core provide a good opportunity to assess changes in the intensity and position of the Benguela Current System and the Subtropical Convergence, two key features of the ocean-climate system in the south Atlantic. This record can be also used to evaluate the possible influence of Agulhas Current from the throughflow of the Indian Ocean into the South Atlantic. The planktonic foraminifer...
Tipo: Text
Palavras-chave: Paleoceanography; Late Quaternary; Micropaleontology; South Atlantic.
Ano: 1999
URL: https://archimer.ifremer.fr/doc/00239/35070/34563.pdf

The structure of rocky reef fish assemblages across a nearshore to coastal islands' gradient in Southeastern Brazil
Provedor de dados: 83
Autores: Gibran,Fernando Zaniolo; Moura,Rodrigo Leão de.
Local assemblages of fishes associated with reefs are influenced by interactions among the availability of larvae and survival of recruits with subsequent biotic and abiotic forcing, as well as by periodic and episodic disturbances of varying natures and magnitudes. Therefore, besides being structurally heterogeneous and patchily distributed, reef systems are strongly context-dependent due to the influence of a broad array of ecological processes. In order to assess interactions of local factors that influence the distribution and abundance of reef fishes within a coastal mosaic of rocky reefs, we tested the null hypothesis of no significant variation in fish assemblage structure, by comparing 33 sites along the northern coast of the São Paulo State,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Coastal management; São Paulo coast; São Sebastião Channel; South Atlantic; Species richness.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252012000200012

Courtship behavior and spawning of the hairy blenny Labrisomus nuchipinnis (Labrisomidae) in southeastern Brazil
Provedor de dados: 83
Autores: Gibran,Fernando Zaniolo; Santos,Flávia Borges; Santos,Hertz Figueiredo dos; Sabino,José.
Labrisomus nuchipinnis is a diurnal bottom-dwelling sit-and-wait carnivorous fish that inhabits holes and rifts of rocky areas in tropical shallow waters. Here we report on the courtship behavior and spawning of this hairy blenny in southeastern Brazil, with a detailed description and comparison with other Blennioidei. Labrisomus nuchipinnis is a territorial species that was observed courting with more than one female, and presenting a well defined pattern cycle related to reproductive behavior and paternal egg care. Adhesive demersal eggs are laid on small algae-covered rocks at sites with increased current velocity within the male's territory, which may enable higher egg survivorship and shorter developmental time.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mating behavior; Oviposition; Parental care; Blennies; South Atlantic.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300009

Morphological variation in the atlantic genus Siderastrea (Anthozoa, Scleractinia)
Provedor de dados: 84
Autores: Menezes,Natalia; Neves,Elizabeth; Kikuchi,Ruy K.P.; Johnsson,Rodrigo.
Siderastrea is a small genus of scleractinian corals, composed by zooxanthellate massive colonial forms. Besides contributing to the consolidation of the reef structure, represent a group with significant resistance to environmental stress. Until the 70's, its taxonomy was a complicated task, limited by the difficulty in identifying morphotypes. More recently, interspecific boundaries were redefined for 'Atlantic Siderastrea Complex'. However, despite new perspectives, including the occurrence of S. radians and S. siderea for Brazil, morphological patterns are still poorly studied and inconspicuous for several coastal areas. In order to characterize levels of intraspecific and interspecific morphological variation in S. stellata and S. radians,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Systematics; Modular organism; Morphotypes; Zooxanthellate coral; South Atlantic.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492014001600001

A new species of Exogone Ørsted, 1845 (Annelida: Syllidae: Exogoninae) from Brazilian waters
Provedor de dados: 84
Autores: Fukuda,Marcelo Veronesi; Menezes-Moura,Andrezza Ribeiro; Guimarães,Carmen Regina Parisotto; Ruta,Christine.
Abstract We describe herein a new species of the abundant polychaete family Syllidae, Exogone brasiliensis sp. nov. The new species is characterized by a peculiar morphology of anterior body falcigers, with shafts and blades modified specially in chaetigers 1 and 2; falcigers until chaetiger 5 different from those of the rest of the body; and dorsal simple chaetae from midbody onwards unique in the genus, nearly straight, subdistally swollen in one side only, distally rounded. Exogone brasiliensis sp. nov. is described based on detailed morphological analyses under optical and scanning electron microscopes, and compared to its most similar congeners.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: “Polychaeta”; South Atlantic; New species; Brazil.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492019000100247

New records of Pegantha spp. (Hydrozoa: Narcomedusae) off Northern Brazil
Provedor de dados: 84
Autores: Tosetto,Everton Giachini; Neumann-Leitão,Sigrid; Nogueira Júnior,Miodeli.
Abstract Specimens of Pegantha laevis H.B. Bigelow, 1909 and Pegantha triloba Haeckel, 1879 were found in oceanic waters off the northern Brazilian coast. The former species is clearly distinct due to the thickness and shape of peripheral channels, while the latter is recognized mainly due to the exumbrellar furrows and long otoporpae. This study represents the first actual record of P. laevis inside the Brazilian Economic Exclusive zone, since previous reports were far away from the coast, and clarifies the presence of P. triloba off Brazil.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Jellyfish; Cnidaria; Hydrozoa; Taxonomy; Biodiversity; South Atlantic.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0031-10492018000100247

Distribution and relative abundance of large whales in a former whaling ground off eastern South America
Provedor de dados: 103
Autores: Andriolo,Artur; Rocha,Jesuina M. da; Zerbini,Alexandre N.; Simões-Lopes,Paulo C.; Moreno,Ignacio B.; Lucena,Alineide; Danilewicz,Daniel; Bassoi,Manuela.
Ship-based sighting surveys for cetaceans were conducted in the former whaling ground off the northeastern coast of Brazil. The cruises took place in winter and spring of 1998-2001 with the objectives of investigating current distribution and abundance of cetaceans, particularly large whale species taken during whaling. In 1998 the survey were conducted between the parallels 5°30'W and 9°S and the 200 m isobath and the meridian 033°W. A total of about 3,100 nm were surveyed between 1998 and 2001 Surveys were conducted using line transect methods from about 5-10°S, and from the coast to 33°W. A total of 151 sightings (203 individuals) of large whales were recorded on effort. The Antarctic minke whale - Balaenoptera bonaerensis (Burmeister, 1867) was the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bryde's whale; Minke whale; Sei whale; Sperm whale; South Atlantic.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702010000500011

Polychaetes from a southwestern shallow shelf Atlantic area (Argentina, 38 S) affected by sewage discharge
Provedor de dados: 97
Autores: ELÍAS,RODOLFO; BREMEC,CLAUDIA S; VALLARINO,EDUARDO A.
A benthos-sampling program was carried out in the coastal area of Mar del Plata city in order to know the composition and distribution of infaunal polychaetes living on a subtidal soft-bottom substrate affected by the sewage discharge. Sandy bottoms showed heterogeneous sediment composition and very low organic matter content. Thirty three polychaete species were identified in a range depth between 6.5 to 12.5 m. A comparison with data from 30 years ago from adjacent areas deeper than 12 m is herein presented. Polychaete distribution was related both to the type of sediment and to the content of organic matter. Owenia fusiformis Delle Chiaje was dominant and peaked at stations near the sewage effluent. Small-sized polychaetes were abundant in the sampling...
Tipo: Journal article
Palavras-chave: Polychaetes; Domestic outfall; Sandy subtidal bottoms; South Atlantic.
Ano: 2001
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000300003

Relação dos peixes coletados nos limites da plataforma continental e nas montanhas submarinas Vitória, Trindade e Martin Vaz, durante a campanha oceanográfica MD-55 Brasil
Provedor de dados: 104
Autores: Andreata,José V.; Séret,Bernard.
The result of an agreement between Universidade Santa Ursula, Rio de Janeiro and the Museum of Natural History of Paris, was the oceanographic campaign MD-55 Brasil which took place between May 6th and June 2nd of 1987, aboard the R/V "Marion Dufresne" of the Terres Australes et Antartique Françaises (TAAF). Samples were collected between latitudes 23º36'40"S and 18º49'S. Ichthyofauna sampled was relatively low, and comprised of just one family of Chondrichthyes (three species) and 50 families of Osteichthyes (104 species). Zenion hololepsis (Goode &amp;amp; Bean, 1895) (Zeniodontidae) is recorded for the first time from the western South Atlantic, as well as is extended the geographic limits for Myrophis frio Jordan &amp;amp; Davis. 1892 (Ophichthidae)...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fish species list; South Atlantic; Continental shelf.
Ano: 1995
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751995000300014

Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of flounders of Rio Grande do Sul State, Brazil
Provedor de dados: 104
Autores: Thatcher,Vernon E.; Pereira Júnior,Joaber.
Brasilochondria riograndensis gen. nov., sp. nov. (Copepoda, Chondracanthidae) a parasite of the flounder, Paralichthys orbignyanus (Valenciennes, 1839), is described. The new genus has a spherical head a post-mandibular "neck" and two pairs of modified biramous legs. In these respects, it resembles Argentinochondria patagonensis Etchegoin, Timi &amp;amp; Sardella, 2003. In the Argentine genus, however, the bulbous head has a medial constriction and the posterior of the female lacks the lateral extensions that are present in the new genus. Pseudolernentoma brasiliensis Luque &amp;amp; Alves, 2003, also resembles the new genus but it lacks the lateral extensions of the trunk and the latter is cylindrical rather than flat. The second leg of the new genus is...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Copepod parasite; Chondracanthid; Southern Brasil; South Atlantic.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752004000300014

Kroyeria brasiliense sp. nov. (Copepoda, Kroyeriidae)a gill parasite of the shark, Galeorhinus vitaminicus de Buen, in Rio Grande do Sul State, Brazil
Provedor de dados: 104
Autores: Thatcher,Vernon E.; Pereira Júnior,Joaber.
Kroyeria brasiliense sp. nov. from the shark, Galeorhinus vitaminicus de Buen, 1950, from Rio Grande do Sul, State, Brazil, is described on the basis of 14 adult females. The new species is superficially similar to Kroyeria deetsi Dippenaar, Benz &amp;amp; Olivier, 2000, but differs from it in the following characters. The maxillipeds of the new species are large and project well beyond the lateral margins of the cephalothorax. Those of K. deetsi are much smaller. The third endopodal segments of K. deetsi are twice as long as the second endopodal segments and are provided with prominent marginal denticles. The second and third endopodal segments of the new species are rounded, of similar length and lack teeth.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Copepod parasite; Kroyeriid; Southern Brazil; South Atlantic.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752006000400027

Modern sedimentation in the Cabo Frio upwelling system, Southeastern Brazilian shelf
Provedor de dados: 42
Autores: Mahiques,Michel M. de; Bícego,Marcia C.; Silveira,Ilson C.A.; Sousa,Silvia H.M.; Lourenço,Rafael A.; Fukumoto,Marina M.
The analyses of Uk'37 paleotemperatures and sedimentological parameters in box cores from the Cabo Frio upwelling zone, southeastern Brazil, were used to understand the modern sedimentation as well as to evaluate the role played by the upwelling process in the sedimentary patterns. Three box-cores located closer to the upwelling area show a general trend of cooling waters taking place in the last 700 years. Since the present upwelling is dependent on local and remote wind regime, a phase of dominating NE winds favors a more effective upward transport of the cold thermocline level South Atlantic CentralWater towards the coast. The intensification in the upwelling regime for the last ca. 700 years can be associated with the strengthening of the NE winds off...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sedimentation; Alkenones; Bulk organic matter; Upwelling; Brazil; South Atlantic.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652005000300013

Euphausiacea diversity in a trans-oceanic transect through the South Atlantic Ocean: the first Atlantic record of Thysanopoda astylata Brinton, 1975
Provedor de dados: 42
Autores: MUXAGATA,ERIK; BARBOSA,CARLA N.; AGOSTINI,VANESSA O.
Abstract: ﻿Information about euphausiids in central South Atlantic Ocean is scarce; hence, we investigated species composition and distribution of euphausiids along a longitudinal transect in this region, with an emphasis on Thysanopoda. Zooplankton samples were collected from 44 stations during the first Transatlantic Commission (Brazil–Africa). Euphausiids comprised 21,390 individuals across larval stages (nauplius, calyptopis, and furcilia) and adults. Furcilia and adults were classified to species level when possible, with a total of 19 identified species. O﻿verall, Euphausia species frequency of occurrence and abundance were highest in samples collected near the African coast, while Thysanopada species dominated near the Brazilian coast. Of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Euphausiids; South Atlantic; Thysanopoda astylata; Zooplankton.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652019000100621

Checklist of the Cnidaria Medusozoa of Brazil
Provedor de dados: 49
Autores: Migotto,Alvaro E.; Marques,Antonio C.; Morandini,André C.; Silveira,Fábio L. da.
Literature records were reviewed to compile a list of species of the marine taxa of Cnidaria Medusozoa recorded for the Brazilian coast. The total number of species of medusozoans so far recorded for Brazil is 373: 347 Hydrozoa, 3 Cubozoa: 23 Scyphozoa.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrozoa; Scyphozoa; Cubozoa; Fauna; South Atlantic; Brazil; Polyp; Medusa.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032002000100010

Synopsis of knowledge on Cnidaria Medusozoa from Brazil
Provedor de dados: 49
Autores: Marques,Antonio C.; Morandini,André C.; Migotto,Alvaro E.
A synopsis of knowledge concerning Medusozoa (Cnidaria) along the Brazilian coast is presented. We generated a data list with all records of medusozoans from Brazil, including information on the distribution of the species and the phase (polyp or medusa) recorded. Currently the number of species of Medusozoa recorded from Brazil is 377 (205 genera and 82 families), with 348 species of hydrozoans, 22 scyphozoans, 3 cubozoans and 1 staurozoan. Geographical and historical analyses were carried out based on the data list. The geographical analysis reveals that knowledge on biodiversity of the group is most inadequate for the North and part of the Northeastern coast. Although the Southeastern coast is the best known region in number of species and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrozoa; Scyphozoa; Cubozoa; Staurozoa; Fauna; South Atlantic; Polyp; Medusa; Brazil.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032003000200007

Intracolonial variation in Siderastrea de Blainville, 1830 (Anthozoa, Scleractinia): taxonomy under challenging morphological constraints
Provedor de dados: 49
Autores: Menezes,Natália Matos de; Neves,Elizabeth Gerardo; Barros,Francisco; Kikuchi,Ruy Kenji Papa de; Johnsson,Rodrigo.
The morphology of sessile invertebrates, such as scleractinian corals, can be controlled by environmental and genetic mechanisms and, consequently, it is highly variable. Morphological variation has puzzled taxonomists by posing challenges to species classification within cryptic species complexes. The 'Atlantic Siderastrea Complex' is a suitable example. Because of overlapping diagnostic traits, the morphological interspecific limits of this group remain controversial and often resulted in doubtful synonyms. In addition, the recent identification of the Caribbean S. radians in the Southwestern Atlantic has revealed that intraspecific variation has been equivocally assessed. Traditionally, hierarchical categories of variation have been the criteria used to...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Systematics; Siderastrea radians; Morphological variation; Biogeographic expansion; South Atlantic.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032013000100012

The composition and new records of micro- and mesophytoplankton near the Vitória-Trindade Seamount Chain
Provedor de dados: 49
Autores: Lubiana,Karoline Magalhães Ferreira; Dias Júnior,Camilo.
Abstract In spite of the length of the Brazilian coastline, studies of marine phytoplankton species in offshore areas have been largely neglected. Regarding phytoplankton species composition, the aim was to assess biodiversity status, species frequency, and the similarities at different sites along the Vitoria-Trindade Seamount Chain. Phytoplankton net samples were analyzed. One hundred and seventy five infrageneric taxa were identified. They represented four phyla, viz., Cyanobacteria, Bacillariophyta, Dinophyta, and Ochrophyta. Dinophyta was the most diverse, and its genus Tripos the largest contributor. This genus also represented more than half of the most common taxa in the sampled area. Thirty-five new infrageneric taxa were recorded, 12 of which are...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: South Atlantic; Tripos; Oceanic islands; Phytoplankton; Biodiversity.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032016000300206

The effects of fish feeding by visitors on reef fish in a Marine Protected Area open to tourism
Provedor de dados: 49
Autores: Paula,Yuri Cruz de; Schiavetti,Alexandre; Sampaio,Cláudio L. S.; Calderon,Emiliano.
Abstract: Coral reef-based tourism has risen sharply across the globe, coupled with an increase in fish feeding by visitors. Studies indicate that fish feeding is one of the leading causes of changes in distribution patterns, abundance, the structure of marine fish communities, and fish behavior. The aim of this study was to determine the effect of human presence and fish feeding on the behavior of reef fish by conducting in situ experiments in tide pools in a Marine Protected Area located at the northern limit of the Abrolhos Bank in the South Atlantic Ocean. Eight feeding sessions were conducted and filmed, resulting in a total of 160 minutes of video footage. Each filming session recorded four different experimental conditions alternating between human...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Abudefduf saxatilis; Behavior; Fish feeding; In situ experiment; South Atlantic; Tide pools.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1676-06032018000300309

Food resource utilization of the skates Rioraja agassizii (Müller &amp;amp; Henle, 1841) and Psammobatis extenta (Garman, 1913) on the continental shelf off Ubatuba, South-eastern Brazil
Provedor de dados: 57
Autores: MUTO,E. Y.; SOARES,L. S. H.; GOITEIN,R.
The feeding habits of Rioraja agassizii (syn. Raja agassizii) and Psammobatis extenta (syn. Psammobatis glansdissimilis) of the South-eastern Brazilian coast were studied by means of stomach content analysis. The samples were obtained on eight seasonal oceanographic cruises, carried out between October 1985 and July 1987. The importance of each food item was evaluated on the basis of the Index of Relative Importance and the feeding similarity by Percentage of Similarity. The results indicated that both species are benthic feeders, preying mainly on Crustacea, especially Amphipoda, Caridea and Brachyura. Teleostei were also important for R. agassizii. Seasonal variation of the diet seems to be associated with the availability of the prey, whose distribution...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Rajidae; Stomach content; Feeding habits; South Atlantic; Brazil.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-71082001000200005