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| Registros recuperados: 38 | |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 (< 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| Registros recuperados: 38 | |
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