Consulta: subjectFacets:"Southern Ocean"
Registros recuperados: 86
Data/hora: 07/06/2024 01:58:41

Emergence of Global Adaptive Governance for Stewardship of Regional Marine Resources
Provedor de dados: 7
Autores: Folke, Carl; Stockholm Resilience Centre, Stockholm University; Beijer Institute of Ecological Economics, Royal Swedish Academy of Sciences; carl.folke@beijer.kva.se.
Overfishing has historically caused widespread stock collapses in the Southern Ocean. Until recently, illegal, unreported, and unregulated (IUU) fishing threatened to result in the collapse of some of the few remaining valuable fish stocks in the region and vulnerable seabird populations. Currently, this unsustainable fishing has been reduced to less than 10% of former levels. We describe and analyze the emergence of the social-ecological governance system that made it possible to curb the fisheries crisis. For this purpose, we investigated the interplay between actors, social networks, organizations, and institutions in relation to environmental outcomes. We drew on a diversity of methods, including qualitative interviews, quantitative social network and...
Tipo: Peer-Reviewed Insight
Palavras-chave: CCAMLR; Governance; IUU fishing; Marine ecology; Southern Ocean; Toothfish.
Ano: 2013

Observing the Local Emergence of the Southern Ocean Residual-Mean Circulation
Provedor de dados: 5
Autores: Sévellec, Florian; Naveira Garabato, A; Vic, Clement; Ducousso, N.
The role of mesoscale turbulence in maintaining the mean buoyancy structure and overturning circulation of the Southern Ocean is investigated through a 2‐year‐long, single‐mooring record of measurements in Drake Passage. The buoyancy budget of the area is successively assessed within the Eulerian and the Temporal‐Residual‐Mean frameworks. We find that a regime change occurs on timescales of 1 day to 100 days, characteristic of mesoscale dynamics, whereby the eddy‐induced turbulent horizontal advection balances the vertical buoyancy advection by the mean flow. We use these diagnostics to reconstruct the region's overturning circulation, which is found to entail an equatorward downwelling of Antarctic Intermediate and Bottom Waters and a poleward upwelling...
Tipo: Text
Palavras-chave: Southern Ocean; Meridional overturning; Mesoscale turbulence; Residual-mean circulation; Eulerian circulation; Mooring measurements.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00485/59655/62687.pdf

Antarctic, Sub-Antarctic and cold temperate echinoid database
Provedor de dados: 5
Autores: Pierrat, Benjamin; Saucede, Thomas; Festeau, Main; David, Bruno.
This database includes spatial data of Antarctic, Sub-Antarctic and cold temperate echinoid distribution (Echinodermata: Echinoidea) collected during many oceanographic campaigns led in the Southern Hemisphere from 1872 to 2010. The dataset lists occurrence data of echinoid distribution south of 35 degrees S latitude, together with information on taxonomy (from species to genus level), sampling sources (cruise ID, sampling dates, ship names) and sampling sites (geographic coordinates and depth). Echinoid occurrence data were compiled from the Antarctic Echinoid Database (David et al. 2005a), which integrates records from oceanographic cruises led in the Southern Ocean until 2003. This database has been upgraded to take into account data from oceanographic...
Tipo: Text
Palavras-chave: Southern Ocean; Echinoids; Antarctic species; Sub-Antarctic species; Cold temperate species.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00296/40763/39773.pdf

Anthropogenic CO(2) in the Southern Ocean: Distribution and inventory at the Indian-Atlantic boundary (World Ocean Circulation Experiment line I6)
Provedor de dados: 5
Autores: Lo Monaco, C; Metzl, N; Poisson, A; Brunet, C; Schauer, B.
The Southern Ocean, where various water masses are formed ( mode, intermediate, deep, and bottom waters), has a high potential to absorb anthropogenic CO(2) ( C ant). However, most data-based and model estimates indicate low C(ant) inventories south of 50 degrees S. In order to investigate this paradox, the distribution of C(ant) is estimated between South Africa and Antarctica ( World Ocean Circulation Experiment ( WOCE) line I6) based on a back-calculation technique previously used in the North Atlantic ( Kortzinger et al., 1998) and adapted here for application in the Southern Ocean. At midlatitudes (30 degrees-50 degrees S), formation and spreading of mode and intermediate waters results in a deep penetration of C(ant) ( down to 2000 m). South of 50...
Tipo: Text
Palavras-chave: Anthropogenic CO2; Southern Ocean; WOCE.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00233/34409/32823.pdf

Metrics for the Evaluation of the Southern Ocean in Coupled Climate Models and Earth System Models
Provedor de dados: 5
Autores: Russell, Joellen L.; Kamenkovich, Igor; Bitz, Cecilia; Ferrari, Raffaele; Gille, Sarah T.; Goodman, Paul J.; Hallberg, Robert; Johnson, Kenneth; Khazmutdinova, Karina; Marinov, Irina; Mazloff, Matthew; Riser, Stephen; Sarmiento, Jorge L.; Speer, Kevin; Talley, Lynne D.; Wanninkhof, Rik.
The Southern Ocean is central to the global climate and the global carbon cycle, and to the climate's response to increasing levels of atmospheric greenhouse gases, as it ventilates a large fraction of the global ocean volume. Global coupled climate models and earth system models, however, vary widely in their simulations of the Southern Ocean and its role in, and response to, the ongoing anthropogenic trend. Due to the region's complex water-mass structure and dynamics, Southern Ocean carbon and heat uptake depend on a combination of winds, eddies, mixing, buoyancy fluxes, and topography. Observationally based metrics are critical for discerning processes and mechanisms, and for validating and comparing climate and earth system models. New observations...
Tipo: Text
Palavras-chave: Southern Ocean; Heat uptake; Carbon uptake; Observationally based metrics.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00673/78491/80788.pdf

The control of the Southern Hemisphere Westerlies on the position of the Subtropical Front
Provedor de dados: 5
Autores: De Boer, Agatha M.; Graham, Robert M.; Thomas, Matthew; Kohfeld, Karen E.
In recent years the latitudinal position of the Subtropical Front (STF) has emerged as a key parameter in the global climate. A poleward positioned front is thought to allow a greater salt flux from the Indian to the Atlantic Ocean and so drive a stronger Atlantic Meridional Overturning Circulation. Here the common view that the STF aligns with the zero wind stress curl (WSC) is challenged. Based on the STF climatologies of Orsi et al. (1995), Belkin and Gordon (1996), Graham and De Boer (2013), and on satellite scatterometry winds, we find that the zero WSC contour lies on average approximate to 10 degrees, approximate to 8 degrees, and approximate to 5 degrees poleward of the front for the three climatologies, respectively. The circulation in the region...
Tipo: Text
Palavras-chave: Subtropical Front; Wind stress curl; Southern Ocean; Satellite data; Fronts; Dynamical Subtropical Front.
Ano: 2013
URL: http://archimer.ifremer.fr/doc/00169/28046/26248.pdf

The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing
Provedor de dados: 5
Autores: Pellichero, Violaine; Sallee, Jean-baptiste; Schmidtko, Sunke; Roquet, Fabien; Charrassin, Jean-benoit.
The oceanic mixed layer is the gateway for the exchanges between the atmosphere and the ocean; in this layer, all hydrographic ocean properties are set for months to millennia. A vast area of the Southern Ocean is seasonally capped by sea-ice, which alters the characteristics of the ocean mixed layer. The interaction between the ocean mixed layer and sea-ice plays a key role for water mass transformation, the carbon cycle, sea-ice dynamics, and ultimately for the climate as a whole. However, the structure and characteristics of the under-ice mixed layer are poorly understood due to the sparseness of in situ observations and measurements. In this study, we combine distinct sources of observations to overcome this lack in our understanding of the polar...
Tipo: Text
Palavras-chave: Southern Ocean; Mixed layer; Sea-ice; Elephant seals; Salt budget; Heat budget.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00383/49400/49901.pdf

Factors regulating the Great Calcite Belt in the Southern Ocean and its biogeochemical significance
Provedor de dados: 5
Autores: Balch, William M.; Bates, Nicholas R.; Lam, Phoebe J.; Twining, Benjamin S.; Rosengard, Sarah Z.; Bowler, Bruce C.; Drapeau, Dave T.; Garley, Rebecca; Lubelczyk, Laura C.; Mitchell, Catherine; Rauschenberg, Sara.
The Great Calcite Belt (GCB) is a region of elevated surface reflectance in the Southern Ocean (SO) covering similar to 16% of the global ocean and is thought to result from elevated, seasonal concentrations of coccolithophores. Here we describe field observations and experiments from two cruises that crossed the GCB in the Atlantic and Indian sectors of the SO. We confirm the presence of coccolithophores, their coccoliths, and associated optical scattering, located primarily in the region of the subtropical, Agulhas, and Subantarctic frontal regions. Coccolithophore-rich regions were typically associated with high-velocity frontal regions with higher seawater partial pressures of CO2 (pCO(2)) than the atmosphere, sufficient to reverse the direction of gas...
Tipo: Text
Palavras-chave: Coccolithophores; Trace metals; Carbonate chemistry; Southern Ocean; Subantarctic Front; Subtropical Front.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00383/49412/49883.pdf

Polar Front around the Kerguelen Islands: An up-to-date determination and associated circulation of surface/subsurface waters
Provedor de dados: 5
Autores: Park, Young-hyang; Durand, Isabelle; Kestenare, Elodie; Rougier, Gilles; Zhou, Meng; D'Ovidio, Francesco; Cotte, Cedric; Lee, Jae-hak.
The circulation of iron-rich shelf waters around the Kerguelen Islands plays a crucial role for a climatically important, annually recurrent phytoplankton spring bloom over the sluggish shelf region and its downstream plume area along the Antarctic circumpolar flow. However, there is a long-standing confusion about the Polar Front (PF) in the Kerguelen region due to diverse suggestions in the literature for its geographical location with an extreme difference over 10° of latitude. Based on abundant historical hydrographic data, the in situ hydrographic and current measurements during the 2011 KEOPS2 cruise, satellite chlorophyll images, and altimetry-derived surface velocity fields, we determine and validate an up-to-date location of the PF around the...
Tipo: Text
Palavras-chave: Polar Front; Kerguelen; Southern Ocean.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00244/35485/33995.pdf

Epimeria of the Southern Ocean with notes on their relatives (Crustacea, Amphipoda, Eusiroidea)
Provedor de dados: 5
Autores: D'Udekem D'Acoz, Cedric; Verheye, Marie L.
The present monograph includes general systematic considerations on the family Epimeriidae, a revision of the genus Epimeria Costa in Hope, 1851 in the Southern Ocean, and a shorter account on putatively related eusiroid taxa occurring in Antarctic and sub-Antarctic seas. The former epimeriid genera Actinacanthus Stebbing, 1888 and Paramphithoe Bruzelius, 1859 are transferred to other families, respectively to the Acanthonotozomellidae Coleman &amp; J.L. Barnard, 1991 and the herein re-established Paramphithoidae G.O. Sars, 1883, so that only Epimeria and Uschakoviella Gurjanova, 1955 are retained within the Epimeriidae Boeck, 1871. The genera Apherusa Walker, 1891 and Halirages Boeck, 1891, which are phylogenetically close to Paramphithoe, are also...
Tipo: Text
Palavras-chave: Alexandrella; Amphipoda; Epimeria; Eusiroidea; Senticaudata; Southern Ocean.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00406/51743/52328.pdf

Biogeochemical sensor performance in the SOCCOM profiling float array
Provedor de dados: 5
Autores: Johnson, Kenneth S.; Plant, Joshua N.; Coletti, Luke J.; Jannasch, Hans W.; Sakamoto, Carole M.; Riser, Stephen C.; Swift, Dana D.; Williams, Nancy L.; Boss, Emmanuel; Haentjens, Nils; Talley, Lynne D.; Sarmiento, Jorge L.
The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program has begun deploying a large array of biogeochemical sensors on profiling floats in the Southern Ocean. As of February 2016, 86 floats have been deployed. Here the focus is on 56 floats with quality-controlled and adjusted data that have been in the water at least 6 months. The floats carry oxygen, nitrate, pH, chlorophyll fluorescence, and optical backscatter sensors. The raw data generated by these sensors can suffer from inaccurate initial calibrations and from sensor drift over time. Procedures to correct the data are defined. The initial accuracy of the adjusted concentrations is assessed by comparing the corrected data to laboratory measurements made on samples collected...
Tipo: Text
Palavras-chave: Profiling floats; Oxygen sensors; PH sensors; Nitrate sensors; Bio-optical sensors; Southern Ocean.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00662/77398/78993.pdf

Differentiating Lithogenic Supplies, Water Mass Transport, and Biological Processes On and Off the Kerguelen Plateau Using Rare Earth Element Concentrations and Neodymium Isotopic Compositions
Provedor de dados: 5
Autores: Grenier, Melanie; Garcia-solsona, Ester; Lemaitre, Nolwenn; Trull, Thomas W.; Bouvier, Vincent; Nonnotte, Philippe; Van Beek, Pieter; Souhaut, Marc; Lacan, Francois; Jeandel, Catherine.
Distributions of dissolved rare earth element (REE) concentrations and neodymium isotopic compositions (expressed as epsilon(Nd)) of seawater over and off the Kerguelen Plateau in the Southern Ocean are presented. The sampling took place during the austral spring bloom in October-November 2011 (KEOPS2 project, GEOTRACES process study) and aimed to further the investigations of the KEOPS1 austral summer study in terms of sources and transport of lithogenic material, and to investigate the impact of local biogeochemical cycles on the REE distributions. The REE signature of the coastal eastern Kerguelen Islands waters was characterized by negative europium anomalies (Eu/Eu*) and negative epsilon(Nd) in filtered samples. By contrast, the unfiltered sample...
Tipo: Text
Palavras-chave: Southern Ocean; Kerguelen Islands; Rare earth elements; Fractionation; Anomalies; Lithogenic; Biologic; GEOTRACES.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00616/72764/72274.pdf

Antarctic icebergs distributions 1992-2014
Provedor de dados: 5
Autores: Tournadre, Jean; Bouhier, Nicolas; Girard-ardhuin, Fanny; Remy, F.
Basal melting of floating ice shelves and iceberg calving constitute the two almost equal paths of freshwater flux between the Antarctic ice cap and the Southern Ocean. The largest icebergs (&gt;100 km2) transport most of the ice volume but their basal melting is small compared to their breaking into smaller icebergs that constitute thus the major vector of freshwater. The archives of nine altimeters have been processed to create a database of small icebergs (&lt;8 km2) within open water containing the positions, sizes, and volumes spanning the 1992–2014 period. The intercalibrated monthly ice volumes from the different altimeters have been merged in a homogeneous 23 year climatology. The iceberg size distribution, covering the 0.1–10,000 km2 range,...
Tipo: Text
Palavras-chave: Iceberg; Altimetry; Southern Ocean.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00307/41863/41114.pdf

Changes in ocean circulation and carbonate chemistry in the Australian sector of the Southern Ocean during the last 500,000 years
Provedor de dados: 5
Autores: Sturm, Arne.
Stable oxygen and carbon isotope records and carbonate dissolution proxy records were used to reconstruct glacial/interglacial changes in ocean circulation, deep-water ventilation and carbonate chemistry in the Australian sector of the Southern Ocean for the last 500 kyr. Carbonate preservation records indicated a longitudinal gradient in Southern Ocean deep-water alkalinity at 110°E that persisted through glacial/interglacial stages. In contrast to previous studies suggesting the “Atlantic-type” carbonate preservation pattern in the entire Southern Ocean with enhanced carbonate preservation during interglacials and increased carbonate dissolution during glacials, this study, however, revealed that the reversed “Pacific-type” pattern of...
Tipo: Text
Palavras-chave: Late Pleistocene; Southern Ocean; Deep-water circulation; Carbonate chemistry; Epibenthic delta13C; Carbonate dissolution; Surface-water circulation.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00499/61034/64441.pdf

Changing Biogeochemistry of the Southern Ocean and Its Ecosystem Implications
Provedor de dados: 5
Autores: Henley, Sian F.; Cavan, Emma L.; Fawcett, Sarah E.; Kerr, Rodrigo; Monteiro, Thiago; Sherrell, Robert M.; Bowie, Andrew R.; Boyd, Philip W.; Barnes, David K. A.; Schloss, Irene R.; Marshall, Tanya; Flynn, Raquel; Smith, Shantelle.
The Southern Ocean plays a critical role in regulating global climate as a major sink for atmospheric carbon dioxide (CO2), and in global ocean biogeochemistry by supplying nutrients to the global thermocline, thereby influencing global primary production and carbon export. Biogeochemical processes within the Southern Ocean regulate regional primary production and biological carbon uptake, primarily through iron supply, and support ecosystem functioning over a range of spatial and temporal scales. Here, we assimilate existing knowledge and present new data to examine the biogeochemical cycles of iron, carbon and major nutrients, their key drivers and their responses to, and roles in, contemporary climate and environmental change. Projected increases in...
Tipo: Text
Palavras-chave: Southern Ocean; Biogeochemistry; Primary production; Iron; Nutrients; Carbon; Ecosystem; Ocean acidification.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00676/78831/81113.pdf

Contamination par les organochlorés des dauphins de Commerson des îles Kerguelen
Provedor de dados: 5
Autores: Abarnou, Alain; Robineau, Daniel; Michel, Pierre.
Top predators like marine mammals have been intensively used for monitoring the contamination of the marine environment, particularly in industrialized coastal areas of the Northern Atlantic Ocean. Such data concerning contamination in the Southern hemisphere are very scarce. Samples were taken in the fatty protuberance of the forehead (melon) from eleven Commerson's dolphins (Cephalorhynchus commersonii, Lacépède, 1804) caught in the coastal waters of the Kerguelen Islands (Southern Indian Ocean). They were analyzed for DDT, PCB and HCB, using capillary gaz chromatography. The levels of contamination [DDT= 1 150 ± 650, PCB = 1 150 ± 770, HCB=500±300ng/g of extracted matter (lipids)] are between ten and a hundred times Jess than those found in similar...
Tipo: Text
Palavras-chave: Organochlorés; Mammifères marins; Océan austral; Iles Kerguelen; Organochlorines; Marine mammals; Southern Ocean; Kerguelen Islands.
Ano: 1986
URL: http://archimer.ifremer.fr/doc/00111/22273/19948.pdf

Effects of phytoplankton community composition and productivity on sea surface pCO(2) variations in the Southern Ocean
Provedor de dados: 5
Autores: Takao, Shintaro; Nakaoka, Shin-ichiro; Hashihama, Fuminori; Shimada, Keishi; Yoshikawa-inoue, Hisayuki; Hirawake, Toru; Kanda, Jota; Hashida, Gen; Suzuki, Koji.
The Southern Ocean is a vast net sink for atmospheric carbon dioxide (CO2), with marine phytoplankton playing a crucial role in CO2 fixation. We assessed how changes in the dominant phytoplankton community and net primary productivity (NPP) affected variations in the partial pressure of CO2 in surface water (pCO(2)(sw)) in the Indian sector of the Southern Ocean during austral summer. pCO2sw was negatively correlated with total phytoplankton and diatom abundances, as estimated from pigment signatures, in the zone south of the Antarctic Circumpolar Current; however, pCO(2)(sw) was not correlated with haptophyte abundance. Additionally, a stronger correlation was found between pCO(2)(sw) and total phytoplankton NPP than between chlorophyll a concentration...
Tipo: Text
Palavras-chave: Phytoplankton community composition; Diatoms; Southern Ocean; Net primary productivity; Carbon dioxide.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00676/78836/81084.pdf

Autonomous observing platform CO2 data shed new light on the Southern Ocean carbon cycle
Provedor de dados: 5
Autores: Olsen, Are.
While the number of surface ocean CO2 partial pressure (pCO(2)) measurements has soared the recent decades, the Southern Ocean remains undersampled. Williams et al. (2017) now present pCO(2) estimates based on data from pH-sensor equipped Bio-Argo floats, which have been measuring in the Southern Ocean since 2014. The authors demonstrate the utility of these data for understanding the carbon cycle in this region, which has a large influence on the distribution of CO2 between the ocean and atmosphere. Biogeochemical sensors deployed on autonomous platforms hold the potential to shape our view of the ocean carbon cycle in the coming decades.
Tipo: Text
Palavras-chave: Ocean carbon; Southern Ocean; Autonomous observations.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00661/77325/78792.pdf

Water Mass and Biogeochemical Variability in the Kerguelen Sector of the Southern Ocean: A Machine Learning Approach for a Mixing Hotspot
Provedor de dados: 5
Autores: Rosso, Isabella; Mazloff, Matthew R.; Talley, Lynne D.; Purkey, Sarah G.; Freeman, Natalie M.; Maze, Guillaume.
The Southern Ocean (SO) is one of the most energetic regions in the world, where strong air‐sea fluxes, oceanic instabilities, and flow‐topography interactions yield complex dynamics. The Kerguelen Plateau (KP) region in the Indian sector of the SO is a hotspot for these energetic dynamics, which result in large spatio‐temporal variability of physical and biogeochemical (BGC) properties throughout the water column. Data from Argo floats (including biogeochemical) are used to investigate the spatial variability of intermediate and deep water physical and BGC properties. An unsupervised machine learning classification approach is used to organize the float profiles into five SO frontal zones based on their temperature and salinity structure between 300 and...
Tipo: Text
Palavras-chave: Southern Ocean; Kerguelen Plateau; Argo; Unsupervised clustering; Machine learning.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00613/72471/71438.pdf

Reassessing Southern Ocean Air-Sea CO2 Flux Estimates With the Addition of Biogeochemical Float Observations
Provedor de dados: 5
Autores: Bushinsky, Seth M.; Landschuetzer, Peter; Roedenbeck, Christian; Gray, Alison R.; Baker, David; Mazloff, Matthew R.; Resplandy, Laure; Johnson, Kenneth S.; Sarmiento, Jorge L.
New estimates of pCO(2) from profiling floats deployed by the Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) project have demonstrated the importance of wintertime outgassing south of the Polar Front, challenging the accepted magnitude of Southern Ocean carbon uptake (Gray et al., 2018, ). Here, we put 3.5 years of SOCCOM observations into broader context with the global surface carbon dioxide database (Surface Ocean CO2 Atlas, SOCAT) by using the two interpolation methods currently used to assess the ocean models in the Global Carbon Budget (Le Quere et al., 2018, ) to create a ship-only, a float-weighted, and a combined estimate of Southern Ocean carbon fluxes (&lt;35 degrees S). In our ship-only estimate, we calculate a mean uptake...
Tipo: Text
Palavras-chave: Southern Ocean; Biogeochemical profiling floats; SOCCOM; Global carbon cycle.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00675/78719/81007.pdf

Southern High Latitude Squat Lobsters: Galatheoidea and Chirostyloidea from Macquarie Ridge with Description of a New Species of Uroptychus
Provedor de dados: 5
Autores: Ahyong, Shane T.; Schnabel, Kareen E.; Baba, Keiji.
Macquarie Ridge is one of the southernmost seamount ridges, spanning 1600 kilometres from the southern tip of New Zealand to the Australia-Pacific-Antarctic triple junction halfway to Antarctica. Squat lobsters, superfamilies Chirostyloidea and Galatheoidea, are highly diverse at low and mid-latitudes, declining rapidly towards the poles; only 15 of the more than 1000 species have been recorded south of 50 degrees S. Prior to the present study, one species of squat lobster (Munidopsis pyrochela, Munidopsidae) was known from the Macquarie Ridge, but recent research voyages in 2003 and 2008 collected a further five species from both superfamilies and three families. Uroptychus tracey (Chirostylidae) is new to science. Uroptychus insignis (Henderson, 1885) is...
Tipo: Text
Palavras-chave: Anomura; Galatheoidea; Chirostyloidea; New Zealand; Macquarie Ridge; Southern Ocean; Seamount.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00351/46250/46100.pdf

Circumpolar structure and distribution of the Antarctic Circumpolar Current fronts: 1. Mean circumpolar paths
Provedor de dados: 5
Autores: Sokolov, Serguei; Rintoul, Stephen R.
High resolution hydrographic sections and maps of the gradient of sea surface height (SSH) reveal that the Antarctic Circumpolar Current (ACC) consists of multiple jets or frontal filaments. Here we use a 15 year time series of SSH observations to determine the circumpolar structure and distribution of the ACC fronts. The jets are consistently aligned with particular streamlines along the entire circumpolar path, confirming and extending the results of an earlier study restricted to the region south of Australia. The intensity of the fronts (as measured by the cross-front gradient of SSH) varies along the fronts and the individual branches merge and diverge, often in response to interactions with bathymetry. Maps of absolute velocity at 1000 m depth...
Tipo: Text
Palavras-chave: Southern Ocean; Antarctic Circumpolar Current.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00253/36387/34931.pdf

Nutrient cycling in the Indian sector of the Southern Ocean over the last 50,000 years
Provedor de dados: 5
Autores: Crosta, X; Shemesh, A; Etourneau, J; Yam, R; Billy, I; Pichon, Jj.
Most high-southern latitude records of carbon and nitrogen isotopic ratios and elemental ratios are from the Antarctic and Polar Front zones, thus hindering a comprehensive view of nutrient cycling in the Southern Ocean. We present, for the first time, two records from the Subantarctic Zone and the southern Subtropical Zone of the Indian Ocean. These records provide a latitudinal transect covering the main oceanographic systems of the Southern Ocean. Carbon and nitrogen content of the diatom-bound organic matter increases during the last glacial in the Antarctic and Subantarctic zones but does not show a clear climate-related signal in the Subtropical Zone. Comparison of these records with sea-surface temperatures reconstructed at the core locations and...
Tipo: Text
Palavras-chave: Diatoms; Nutrient cycling; Southern Ocean.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00230/34075/32543.pdf

Decreased calcification in the Southern Ocean over the satellite record
Provedor de dados: 5
Autores: Freeman, Natalie M.; Lovenduski, Nicole S.
Widespread ocean acidification is occurring as the ocean absorbs anthropogenic carbon dioxide from the atmosphere, threatening marine ecosystems, particularly the calcifying plankton that provide the base of the marine food chain and play a key role within the global carbon cycle. We use satellite estimates of particulate inorganic carbon (PIC), surface chlorophyll, and sea surface temperature to provide a first estimate of changing calcification rates throughout the Southern Ocean. From 1998 to 2014 we observe a 4% basin-wide reduction in summer calcification, with approximate to 9% reductions in large regions (approximate to 1 x 10(6) km(2)) of the Pacific and Indian sectors. Southern Ocean trends are spatially heterogeneous and primarily driven by...
Tipo: Text
Palavras-chave: Southern Ocean; Calcification; Particulate inorganic carbon; Carbonate ion; Antarctic polar front.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00292/40371/38941.pdf

Antarctic climate change and the environment
Provedor de dados: 5
Autores: Convey, P.; Bindschadler, R.; Di Prisco, G.; Fahrbach, E.; Gutt, J.; Hodgson, D. A.; Mayewski, P. A.; Summerhayes, C. P.; Turner, J.; ACCE CONSORTIUM.
The Antarctic climate system varies on timescales from orbital, through millennial to sub-annual, and is closely coupled to other parts of the global climate system. We review these variations from the perspective of the geological and glaciological records and the recent historical period from which we have instrumental data (similar to the last 50 years). We consider their consequences for the biosphere, and show how the latest numerical models project changes into the future, taking into account human actions in the form of the release of greenhouse gases and chlorofluorocarbons into the atmosphere. In doing so, we provide an essential Southern Hemisphere companion to the Arctic Climate Impact Assessment.
Tipo: Text
Palavras-chave: Antarctica; Biology; Environmental change; Geology; Glaciology; Southern Ocean.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00292/40357/82998.pdf

Matching zooplankton abundance and environment in the South Indian Ocean and Southern Ocean
Provedor de dados: 5
Autores: Godet, Claire; Robuchon, Marine; Leroy, Boris; Cotté, Cedric; Baudena, Alberto; Da Silva, Ophélie; Fabri-ruiz, Salomé; Lo Monaco, Claire; Sergi, Sara; Koubbi, Philippe.
Distinguishing regions based on the geographic distribution of both abiotic factors and living organisms is an old but still actual central issue for biogeographers. In the Southern Ocean, the few existing regionalization studies have been carried out either at very large scales or on the relatively small region around the Sub-Antarctic islands of Kerguelen and the Crozet archipelagos. However, regionalization studies at meso-scales (100–300 km) covering the Indian part of the Southern Ocean and adjacent South Indian Ocean are scarce. These waters, ranging from the Subtropical to the polar region, are home to large populations of well-studied top predators that depend on the biomass of less known mid-trophic level species such as zooplankton. To fill those...
Tipo: Text
Palavras-chave: Bioregionalization; Southern Ocean; Indian Ocean; Pelagic ecosystem; Zooplankton; Continuous plankton recorder.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00643/75474/76309.pdf

Subantarctic Mode Water variability influenced by mesoscale eddies south of Tasmania
Provedor de dados: 5
Autores: Herraiz-borreguero, Laura; Rintoul, Stephen R.
Subantarctic Mode Water (SAMW) is formed by deep mixing on the equatorward side of the Antarctic Circumpolar Current. The subduction and export of SAMW from the Southern Ocean play an important role in global heat, freshwater, carbon, and nutrient budgets. However, the formation process and variability of SAMW remain poorly understood, largely because of a lack of observations. To determine the temporal variability of SAMW in the Australian sector of the Southern Ocean, we used a 15 year time series of repeat expendable bathythermograph sections from 1993 to 2007, seven repeat conductivity-temperature-depth sections from 1991 to 2001, and sea surface height maps. The mean temperature of the SAMW lies between 8.5 degrees C and 9.5 degrees C (mean of 8.8...
Tipo: Text
Palavras-chave: Subantarctic Mode Water; Subantarctic Front; Mesoscale features; Water mass variability; Southern Ocean.
Ano: 2010
URL: https://archimer.ifremer.fr/doc/00253/36385/34926.pdf

A high-resolution record of Southern Ocean intermediate water radiocarbon over the past 30,000 years
Provedor de dados: 5
Autores: Hines, Sophia K. V.; Southon, John R.; Adkins, Jess F.
The circulation of intermediate waters plays an important role in global heat and carbon transport in the ocean and changes in their distribution are closely tied to glacial-interglacial climate change. Coupled radiocarbon and U/Th measurements on deep-sea Desmophyllum dianthus corals allow for the reconstruction of past intermediate water ventilation. We present a high-resolution time series of Antarctic Intermediate Water radiocarbon from 44 corals spanning 30 ka through the start of the Holocene, encompassing the transition into the Last Glacial Maximum (LGM) and the last deglaciation. Corals were collected south of Tasmania from water depths between 1430 and 1950 m with 80% of them between 1500 and 1700 m, giving us a continuous record from a narrow...
Tipo: Text
Palavras-chave: Southern Ocean; Radiocarbon; Glacial interglacial climate change; Meridional overturning circulation; Southern Ocean fronts; Intermediate water.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00497/60838/64466.pdf

Possible effects of global environmental changes on Antarctic benthos: a synthesis across five major taxa
Provedor de dados: 5
Autores: Ingels, Jeroen; Vanreusel, Ann; Brandt, Angelika; Catarino, Ana I.; David, Bruno; De Ridder, Chantal; Dubois, Philippe; Gooday, Andrew J.; Martin, Patrick; Pasotti, Francesca; Robert, Henri.
Because of the unique conditions that exist around the Antarctic continent, Southern Ocean (SO) ecosystems are very susceptible to the growing impact of global climate change and other anthropogenic influences. Consequently, there is an urgent need to understand how SO marine life will cope with expected future changes in the environment. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity to environmental shifts, making it difficult to predict overall community or ecosystem responses. This emphasizes the need for an improved understanding of the Antarctic benthic ecosystem response to global climate change using a multitaxon approach with consideration of different levels of biological...
Tipo: Text
Palavras-chave: Amphipoda; Echinoidea; Foraminifera; Global climate change; Isopoda; Nematoda; Southern Ocean; Zoobenthos.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00296/40762/39758.pdf

Sea ice diatom contributions to Holocene nutrient utilization in East Antarctica
Provedor de dados: 5
Autores: Panizzo, Virginia; Crespin, Julien; Crosta, Xavier; Shemesh, Aldo; Masse, Guillaume; Yam, Ruth; Mattielli, Nadine; Cardinal, Damien.
Combined high-resolution Holocene δ30Sidiat and δ13Cdiat paleorecords are presented from the Seasonal Ice Zone, East Antarctica. Both data sets reflect periods of increased nutrient utilization by diatoms during the Hypsithermal period (circa 7800 to 3500 calendar years (cal years) B.P.), coincident with a higher abundance of open water diatom species (Fragilariopsis kerguelensis), increased biogenic silica productivity (%BSi), and higher regional summer temperatures. The Neoglacial period (after circa 3500 cal years B.P.) is reflected by an increase in sea ice indicative species (Fragilariopsis curta and Fragilariopsis cylindrus, up to 50%) along with a decrease in %BSi and δ13Cdiat (&lt; −18‰ to −23‰). However, over this period, δ30Sidiat data show an...
Tipo: Text
Palavras-chave: Diatoms; Silicon isotopes; Diatom bound carbon isotopes; Seasonal ice zone; Holocene; Southern Ocean.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40157/39098.pdf

Interactions basses fréquences océan-atmosphère dans l’océan Austral
Provedor de dados: 5
Autores: Maze, Guillaume.
Patterns of interannual variability of the ocean- atmosphere coupled system in the Southern Hemisphere ex- tratropics are studied with a simple dynamical model, in or- der to determine the basic physical processes of interaction independently of tropical forcing. The model used is an at- mospheric quasi-geostrophic model coupled to a "slab" oceanic mixed layer, which includes mean geostrophic advection by the Antarctic Circumpolar Current (ACC). The ocean-atmosphere coupling occurs through surface heat fluxes and Ekman cur- rent heat advection. In a fully coupled simulation, the atmos- pheric part of the model, which includes high frequency tran- sient eddies at midlatitudes, exhibits a strong Southern Annu- lar Mode (SAM) as the first mode of variability...
Tipo: Text
Palavras-chave: Climat; Océan Austral; Mode annulaire; Basse fréquence; Interactions océan-atmosphère; Variabilité; Climat; Southern Ocean; Annular mode; Low frequency; Ocean-atmosphere interactions; Variability.
Ano: 2006
URL: http://archimer.ifremer.fr/doc/00186/29734/28147.pdf

Response of the protozooplankton assemblage during the European Iron Fertilization Experiment (EIFEX) in the Antarctic circumpolar current
Provedor de dados: 5
Autores: Assmy, Philipp; Cisewski, Boris; Henjes, Joachim; Klaas, Christine; Montresor, Marina; Smetacek, Victor.
Ocean iron fertilization experiments enable the quantitative study of processes shaping the structure and functioning of pelagic ecosystems following perturbation under in situ conditions. EIFEX was conducted within a stationary eddy adjacent to the Antarctic Polar Front over 38 days in February/March 2004 and induced a massive diatom bloom. Here, we present the responses in abundance and biomass of all identifiable protozooplankton taxa (heterotrophic protists ranging from 2 to 500 mm) during the bloom. Acantharia, dinoflagellates and ciliates together contributed &gt;90% of protozooplankton biomass in the upper 100 m throughout the experiment with heterotrophic nanoflagellates, nassellaria, spumellaria, phaeodaria, foraminifera and the taxopodidean...
Tipo: Text
Palavras-chave: Protozoa; Rhizaria; Sarcodines; Southern Ocean; Top-down control.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40091/39174.pdf

Planktic foraminifer and coccolith contribution to carbonate export fluxes over the central Kerguelen Plateau
Provedor de dados: 5
Autores: Rembauville, M.; Meilland, J.; Ziveri, P.; Schiebel, R.; Blain, S.; Salter, I.
We report the contribution of planktic foraminifers and coccoliths to the particulate inorganic carbon (PIC) export fluxes collected over an annual cycle (October 2011/September 2012) on the central Kerguelen Plateau in the Antarctic Zone (AAZ) south of the Polar Front (PF). The seasonality of PIC flux was decoupled from surface chlorophyll a concentration and particulate organic carbon (POC) fluxes and was characterized by a late summer (February) maximum. This peak was concomitant with the highest satellite-derived sea surface PIC and corresponded to a Emiliania huxleyi coccoliths export event that accounted for 85% of the annual PIC export. The foraminifer contribution to the annual PIC flux was much lower (15%) and dominated by Turborotalita...
Tipo: Text
Palavras-chave: Foraminifer; Coccoliths; Export; Carbonate counter-pump; Kerguelen Plateau; Southern Ocean.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00421/53249/54722.pdf

Coherent seasonal acceleration of the Weddell Sea boundary current system driven by upstream winds
Provedor de dados: 5
Autores: Le Paih, Nicolas; Hattermann, Tore; Boebel, Olaf; Kanzow, Torsten; Lüpkes, Christof; Rohardt, Gerd; Strass, Volker; Herbette, Steven.
The Weddell Sea is of global importance in the formation of dense bottom waters associated with sea‐ice formation and ocean‐ice sheet interaction occurring on the shelf areas. In this context, the Weddell Sea boundary current system (BCS) presents a major conduit for transporting relatively warm water to the Weddell Sea ice shelves and for exporting {some modified form of Wedell Sea deep and bottom waters into the open ocean. This study investigates the downstream evolution of the structure and the seasonality of the BCS along the Weddell Sea continental slope, combining ocean data collected for the past two decades at three study locations. The interannual‐mean geostrophic flow, which follows planetary potential vorticity contours, shifts from being...
Tipo: Text
Palavras-chave: Southern Ocean; Weddell Sea; Antarctic slope current; Surface stress; Flow strength; Teleconnection.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00652/76398/77436.pdf

Evolution of neodymium isotopic signature of seawater during the Late Cretaceous: Implications for intermediate and deep circulation
Provedor de dados: 5
Autores: Moiroud, Mathieu; Puceat, Emmanuelle; Donnadieu, Yannick; Bayon, Germain; Guiraud, Michel; Voigt, Silke; Deconinck, Jean-francois; Monna, Fabrice.
Neodymium isotopic compositions (εNd) have been largely used for the last fifty years as a tracer of past ocean circulation, and more intensively during the last decade to investigate ocean circulation during the Cretaceous period. Despite a growing set of data, circulation patterns still remain unclear during this period. In particular, the identification of the deep-water masses and their spatial extension within the different oceanic basins are poorly constrained. In this study we present new deep-water εNd data inferred from the Nd isotope composition of fish remains and Fe-Mn oxyhydroxide coatings on foraminifera tests, along with new εNd data of residual (partly detrital) fraction recovered from DSDP sites 152 (Nicaraguan Rise), 258 (Naturaliste...
Tipo: Text
Palavras-chave: Cretaceous; Neodymium isotopes; Ocean circulation; Southern Ocean.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00278/38962/37502.pdf

The isotope composition of inorganic Germanium in seawater and deep sea sponges
Provedor de dados: 5
Autores: Guillermic, Maxence; Lalonde, Stefan; Hendry, Katharine R.; Rouxel, Olivier.
Although dissolved concentrations of germanium (Ge) and silicon (Si) in modern seawater are tightly correlated, uncertainties still exist in the modern marine Ge cycle. Germanium stable isotope systematics in marine systems should provide additional constraints on marine Ge sources and sinks, however the low concentration of Ge in seawater presents an analytical challenge for isotopic measurement. Here, we present a new method of pre-concentration of inorganic Ge from seawater which was applied to measure three Ge isotope profiles in the Southern Ocean and deep seawater from the Atlantic and Pacific Oceans. Germanium isotopic measurements were performed on Ge amounts as low as 2.6 ng using a double-spike approach and a hydride generation system coupled to...
Tipo: Text
Palavras-chave: Stable isotopes; Germanium; Silicon; Sponges; Southern Ocean; Chemical oceanography.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00388/49956/50529.pdf

Rapid changes in meridional advection of Southern Ocean intermediate waters to the tropical Pacific during the last 30 kyr
Provedor de dados: 5
Autores: Pena, L. D.; Goldstein, S. L.; Hemming, S. R.; Jones, K. M.; Calvo, E.; Pelejero, C.; Cacho, I.
The Southern Ocean is increasingly recognized as a key player in the general ocean thermohaline circulation and the global climate system during glacial interglacial transitions. In particular, the advection of Southern Ocean intermediate waters (SOIW), like Antarctic Intermediate Water and Sub-Antarctic Mode Water, to the Eastern Equatorial Pacific (EEP), through a so-called "oceanic tunnelling" mechanism, is an important means for rapid transfer of climatic signals (such as heat, fresh water, salt, and chemical species) from high-to-low latitudes. However, information on how intermediate water advection rates changed in the past, and particularly during deglaciations, is fragmentary. We present new results for Nd isotopes (epsilon(Nd)) in cleaned...
Tipo: Text
Palavras-chave: Neodymium isotopes; Planktonic foraminifera; Intermediate water masses; Eastern Equatorial Pacific; Equatorial Undercurrent; Southern Ocean.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00264/37543/36928.pdf

A data assimilating model for estimating Southern Ocean biogeochemistry
Provedor de dados: 5
Autores: Verdy, A.; Mazloff, M. R.
A Biogeochemical Southern Ocean State Estimate (B-SOSE) is introduced that includes carbon and oxygen fields as well as nutrient cycles. The state estimate is constrained with observations while maintaining closed budgets and obeying dynamical and thermodynamic balances. Observations from profiling floats, shipboard data, underway measurements, and satellites are used for assimilation. The years 2008-2012 are chosen due to the relative abundance of oxygen observations from Argo floats during this time. The skill of the state estimate at fitting the data is assessed. The agreement is best for fields that are constrained with the most observations, such as surface pCO(2) in Drake Passage (44% of the variance captured) and oxygen profiles (over 60% of the...
Tipo: Text
Palavras-chave: Southern Ocean; State estimation; Biogeochemistry.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00662/77394/78995.pdf

Estimates of the Southern Ocean general circulation improved by animal-borne instruments
Provedor de dados: 5
Autores: Roquet, Fabien; Wunsch, Carl; Forget, Gael; Heimbach, Patrick; Guinet, Christophe; Reverdin, Gilles; Charrassin, Jean-benoit; Bailleul, Frederic; Costa, Daniel P.; Huckstadt, Luis A.; Goetz, Kimberly T.; Kovacs, Kit M.; Lydersen, Christian; Biuw, Martin; Nost, Ole A.; Bornemann, Horst; Ploetz, Joachim; Bester, Marthan N.; Mcintyre, Trevor; Muelbert, Monica C.; Hindell, Mark A.; Mcmahon, Clive R.; Williams, Guy; Harcourt, Robert; Field, Iain C.; Chafik, Leon; Nicholls, Keith W.; Boehme, Lars; Fedak, Mike A.
Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixed-layer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea...
Tipo: Text
Palavras-chave: Animal-borne sampling; Southern Ocean; State estimation; Hydrography.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00241/35252/33765.pdf

Heat budget of the surface mixed layer south of Africa
Provedor de dados: 5
Autores: Faure, Vincent; Arhan, Michel; Speich, Sabrina; Gladyshev, Sergey.
ARGO hydrographic profiles, two hydrographic transects and satellite measurements of air-sea exchange parameters were used to characterize the properties and seasonal heat budget variations of the Surface Mixed Layer (SML) south of Africa. The analysis distinguishes the Subtropical domain (STZ) and the Subantarctic Zone (SAZ), Polar Frontal Zone (PFZ) and Antarctic Zone (AZ) of the Antarctic Circumpolar Current. While no Subantarctic Mode Water forms in that region, occurrences of deep SML (up to similar to 450 m) are observed in the SAZ in anticyclones detached from the Agulhas Current retroflection or Agulhas Return Current. These are present latitudinally throughout the SAZ, but preferentially at longitudes 10-20A degrees E where, according to previous...
Tipo: Text
Palavras-chave: Ocean surface mixed layer; Heat budget; Southern Ocean; Agulhas Current retroflection.
Ano: 2011
URL: http://archimer.ifremer.fr/doc/00048/15953/15833.pdf

Radiocarbon Evidence for the Contribution of the Southern Indian Ocean to the Evolution of Atmospheric CO     2     over the last 32,000 years
Provedor de dados: 5
Autores: Ronge, Thomas A.; Prange, M.; Mollenhauer, Gesine; Ellinghausen, Maret; Kuhn, G.; Tiedemann, R.
It is widely assumed that the ventilation of the Southern Ocean played a crucial role in driving glacial‐interglacial atmospheric CO2‐levels. So far however, ventilation records from the Indian sector of the Southern Ocean, are widely missing. Here we present reconstructions of water residence times (depicted as ΔΔ14C and Δδ13C) for the last 32,000 years on sediment records from the Kerguelen Plateau and the Conrad Rise (~570‐2500 m water depth), along with simulated changes in ocean stratification from a transient climate model experiment. Our data indicate that Circumpolar Deep Waters in the Indian Ocean were part of the glacial carbon pool. At our sites, close to or bathed by upwelling deep‐waters, we find two pulses of decreasing ΔΔ14C and δ13C values...
Tipo: Text
Palavras-chave: Radiocarbon; Ventilation; Southern Ocean; Younger Dryas; Carbon cycle; Indian Ocean.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00611/72351/71258.pdf

Distribution and inventory of anthropogenic CO(2) in the Southern Ocean: Comparison of three data-based methods
Provedor de dados: 5
Autores: Lo Monaco, C; Goyet, C; Metzl, N; Poisson, A; Touratier, F.
The Southern Ocean is thought to play an important role in the context of global warming and anthropogenic emissions of CO(2) due to its high sensitivity to both climate change and changes in the carbon cycle. Assessing the penetration of anthropogenic CO(2) (C(ant)) into the Southern Ocean is therefore highly relevant to reduce the uncertainties attached to both the present knowledge of anthropogenic carbon inventories and predictions made by current ocean carbon models. This study compares different data-based approaches for estimating the distribution of C(ant) in the ocean: a recently developed method based on the composite Tracer Combining Oxygen, Inorganic Carbon, and Total Alkalinity (TrOCA) and the "historical'' back-calculation methods (the...
Tipo: Text
Palavras-chave: Anthropogenic carbon; Southern Ocean; WOCE.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00233/34405/32827.pdf

Microzooplankton community associated with phytoplankton blooms in the naturally iron-fertilized Kerguelen area (Southern Ocean)
Provedor de dados: 5
Autores: Christaki, Urania; Georges, Clement; Genitsaris, Savvas; Monchy, Sebastien.
The spatial and temporal community composition of microzooplankton (dinoflagellates and ciliates) was assessed in the Kerguelen area (Southern Ocean) during the KEOPS2 cruise in early spring (October-November) 2011. This naturally iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of phytoplankton blooms. Collectively, 97 morphospecies of dinoflagellates and ciliates belonging to 41 genera were identified by microscopy, and 202 Alveolata-related OTUs (operational taxonomical units) were retrieved with tag-pyrosequencing. Microscopy and pyrosequencing data were in accordance, in that diatom-consuming dinoflagellates were the most enhanced taxa in the blooms. Dinoflagellates also showed significant...
Tipo: Text
Palavras-chave: Dinoflagellates; Ciliates; Natural iron fertilization; Southern Ocean.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00351/46255/46080.pdf

Calcification morphotypes of the coccolithophorid Emiliania huxleyi in the Southern Ocean: changes in 2001 to 2006 compared to historical data
Provedor de dados: 5
Autores: Cubillos, J. C.; Wright, S. W.; Nash, G.; De Salas, M. F.; Griffiths, B.; Tilbrook, B.; Poisson, A.; Hallegraeff, G. M.
We conducted a scanning electron microscopic survey of morphological variations in the calcareous nanoplankton species Emiliania huxleyi in Southern Ocean surface water samples collected along a transect from 43 to 64 degrees S and 141 to 145 degrees E during November 2001, October to February 2002/2003, 2003/2004, 2004/2005 and 2005/2006. The results were compared with historical data from a similar transect occupied in December to January 1983/1984 and January to February 1994 and 1995. While E. huxleyi was absent or extremely sparse (0.1 to 1 cells ml(-1)) south of 60 degrees S in 1983/1984 and 1994/1995, this species was consistently present at about 100 cells ml(-1) between 60 and 65 degrees S during 2002 to 2006. The extended geographic range and/or...
Tipo: Text
Palavras-chave: Southern Ocean; Emiliania huxleyi; Calcite saturation state; Ocean acidification.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00236/34735/33191.pdf

Study of the phytoplankton plume dynamics off the Crozet Islands (Southern Ocean): A geochemical-physical coupled approach
Provedor de dados: 5
Autores: Sanial, Virginie; Van Beek, Pieter; Lansard, Bruno; D'Ovidio, Francesco; Kestenare, Elodie; Souhaut, Marc; Zhou, Meng; Blain, Stephane.
Study of the natural iron fertilization in the Southern Ocean Combined geochemical-physical approach to investigate the exchange rates of waters
Tipo: Text
Palavras-chave: Southern Ocean; Crozet Islands; Iron fertilization; Radium; Altimetry; GEOTRACES.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00226/33749/32162.pdf

Subsurface structure of interannual temperature anomalies in the Australian sector of the Southern Ocean
Provedor de dados: 5
Autores: Sokolov, S; Rintoul, Sr.
A 7 year time series of austral summer expendable bathythermograph (XBT) sections between Tasmania and Antarctica is used to describe the subsurface structure of Southern Ocean interannual temperature anomalies. Comparison of the discontinuous XBT record with a continuous (weekly average) satellite-based SST data set confirms that the XBT sampling is adequate to resolve interannual variability. Significant correlations are found between changes in surface and subsurface temperature along much of the section. In the Subantarctic zone, surface and subsurface changes are coherent because deep convection in winter homogenizes the upper 600 m, and the summer mixed layer temperature reflects the preconditioning of the previous winter. At other latitudes the...
Tipo: Text
Palavras-chave: Antarctic circumpolar wave; Southern Ocean; Antarctic circumpolar current; Interannual variability; Decadal variability; Sea surface temperature anomaly.
Ano: 2003
URL: https://archimer.ifremer.fr/doc/00224/33550/32034.pdf

Ba distribution in surface Southern Ocean sediments and export production estimates
Provedor de dados: 5
Autores: Fagel, N; Dehairs, F; Andre, L; Bareille, G; Monnin, C.
We present excess Ba (Baxs) data (i.e., total Ba corrected for lithogenic Ba) for surface sediments from a north-south transect between the Polar Front Zone and the northern Weddell Gyre in the Atlantic sector and between the Polar Front Zone and the Antarctic continent in the Indian sector. Focus is on two different processes that affect excess Ba accumulation in the sediments: sediment redistribution and excess Ba dissolution. The effect of these processes needs to be corrected for in order to convert accumulation rate into vertical rain rate, the flux component that can be linked to export production. In the Southern Ocean a major process affecting Ba accumulation rate is sediment focusing, which is corrected for using excess (230)Th. This correction,...
Tipo: Text
Palavras-chave: Excess Ba; Sediment; Southern Ocean; Export production.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/00223/33392/31868.pdf

New directional wave satellite observations : Towards improved wave forecasts and climate description in Southern Ocean
Provedor de dados: 5
Autores: Aouf, L; Hauser, D; Chapron, Bertrand; Toffoli, A; Tourrain, C; Peureux, Charles.
In spite of continuous improvements of ocean wave models in the last decades, large errors still remain in particular under strongly forced conditions, often encountered in the Southern Ocean, where strong westerly winds generate some of the fiercest waves on Earth in almost unlimited fetch conditions. The newly launched China‐France Oceanography SATellite (CFOSAT) provides directional spectra of ocean waves for both wind seas and swells. Compared to Synthetic Aperture Radar (SAR), it can resolve shorter wavelengths in all directions, which dominate in non‐fully developed wind waves. Here, the assimilation of these CFOSAT wave number components is proved to bring more accurate predictions of wave growth compared to the assimilation of significant wave...
Tipo: Text
Palavras-chave: Assimilation; Directional; Southern Ocean; SWH; Wave age; Wave number.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00668/77996/83370.pdf

Variabilité et origine des apports détritiques dans le secteur indien de l'océan Austral au cours des derniers 30 000 ans
Provedor de dados: 5
Autores: Manthe, Sandrine; Bareille, Gilles; Salvignac, Marie-eve; Labracherie, Monique; Lemoine, Flavien; Labeyrie, Laurent.
The surface water circulation variability in the southeastern Indian Sector has been investigated using micropalaeontological and isotopic analysis in a deep-sea core located near the Subantarctic Front. The frequency and intensity of iceberg and meltwater discharges have been studied by counting detrital grains &gt;45 mu m, by determining their mineralogical composition, and by measuring delta(18)O in the planktonic foraminifera Neogloboquadrina pachyderma sinistral. The variability of hydrologic fronts was determined by estimating the sea surface temperatures (SST) using the Imbrie and Kipp foraminifera transfer function. Four iceberg discharge events were determined between 24 and 12 ka C-14 BP during the last glacial stage. Distinct but low magnitude...
Tipo: Text
Palavras-chave: Océan Austral; Particules détritiques; Minéralogie; Icebergs; Southern Ocean; Ice-rafted-detritus; Mineralogy; Icebergs.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/00220/33162/31670.pdf

The Last Termination in the South Indian Ocean: A unique terrestrial record from Kerguelen Islands (49 ° S) situated within the Southern Hemisphere westerly belt
Provedor de dados: 5
Autores: Van Der Putten, Nathalie; Verbruggen, Cyriel; Bjorck, Svante; Michel, Elisabeth; Disnar, Jean-robert; Chapron, Emmanuel; Moine, Bertrand N.; De Beaulieu, Jacques-louis.
The awareness of the significance of the Southern Ocean in the Earth's climate system has become increasingly obvious. The deglacial atmospheric CO2 rise during warming periods in Antarctica has been attributed to CO2 ventilation from the deep ocean caused by enhanced upwelling around the Antarctic Divergence. It has been hypothesized that, more intense Southern Hemisphere westerly winds aligned with the Antarctic Circumpolar Current due to a southward shift of the wind belt from its Last Glacial Maximum equator-ward position, are the main drivers. Reconstructions of past changes in atmospheric circulation in the Southern Hemisphere are still scarce and the overall picture is patchy with sometimes contradictory results. For obvious reasons, most...
Tipo: Text
Palavras-chave: Palaeoclimatology; Last Termination; Peat record; Kerguelen Islands; Southern Ocean; Indian Ocean; Oceanic Cold Reversal; Southern Hemisphere westerly belt.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00497/60843/64283.pdf

Reconciling down core anticorrelation of diatom carbon and nitrogen isotopic ratios from the Southern Ocean
Provedor de dados: 5
Autores: Crosta, X; Shemesh, A.
[1] Oceanic nutrient cycling in the Southern Ocean is supposed to have an important impact on glacial-interglacial atmospheric CO(2) changes and global climate. In order to characterize such nutrient cycling over the last two climatic cycles we investigated carbon and nitrogen isotopic ratios of diatom-bound organic matter (delta(13)C(diat) and delta(15)N(diat)- respectively) in two cores retrieved form the Atlantic and Indian sectors of the Antarctic Ocean. The two cores show the same isotopic patterns. The delta(13)C(diat) values are depleted during glacial periods and enriched during interglacial periods, indicating lower productivity during cold times. The delta(15)N(diat) values are enriched during glacial periods and depleted during interglacial...
Tipo: Text
Palavras-chave: Southern Ocean; Paleoceanography; Geochemistry; Diatoms.
Ano: 2002
URL: https://archimer.ifremer.fr/doc/00223/33402/31859.pdf

The Biological Pump and Seasonal Variability of pCO(2) in the Southern Ocean: Exploring the Role of Diatom Adaptation to Low Iron
Provedor de dados: 5
Autores: Person, Roland; Aumont, Olivier; Levy, M.
Iron is known to limit primary production in the Southern Ocean (SO). To cope with the lack of this micronutrient, diatoms, a dominant phytoplankton group in this oceanic region, have been shown in cultures to have developed an original adaptation strategy to maintain efficient growth rates despite very low cellular iron quotas, even in low light conditions. Using a global ocean biogeochemical model, we explored the consequences of this physiological adaptation for the biological pump and the seasonal variability of both surface chlorophyll concentrations and surface partial pressure of carbon dioxide (pCO(2)) in this key region for global climate. In the model, we implemented a low intracellular Fe:C requirement in the SO for diatoms uniquely. This...
Tipo: Text
Palavras-chave: Southern Ocean; Diatoms; Physiological adaptation; Biological pump; PCO(2); Seasonal variability.
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00673/78490/80817.pdf

An observing system simulation for Southern Ocean carbon dioxide uptake
Provedor de dados: 5
Autores: Majkut, Joseph D.; Carter, Brendan R.; Froelicher, Thomas L.; Dufour, Carolina O.; Rodgers, Keith B.; Sarmiento, Jorge L.
The Southern Ocean is critically important to the oceanic uptake of anthropogenic CO2. Up to half of the excess CO2 currently in the ocean entered through the Southern Ocean. That uptake helps to maintain the global carbon balance and buffers transient climate change from fossil fuel emissions. However, the future evolution of the uptake is uncertain, because our understanding of the dynamics that govern the Southern Ocean CO2 uptake is incomplete. Sparse observations and incomplete model formulations limit our ability to constrain the monthly and annual uptake, interannual variability and long-term trends. Float-based sampling of ocean biogeochemistry provides an opportunity for transforming our understanding of the Southern Ocean CO2 flux. In this work,...
Tipo: Text
Palavras-chave: Carbon; Southern Ocean; Observational system simulation experiment.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40115/38747.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

Antarctic icebergs melt over the Southern Ocean : climatology and impact on sea ice
Provedor de dados: 5
Autores: Merino, Nacho; Le Sommer, Julien; Durand, Gael; Jourdain, Nicolas C.; Madec, Gurvan; Mathiot, Pierre; Tournadre, Jean.
Recent increase in Antarctic freshwater release to the Southern Ocean is suggested to contribute to change in water masses and sea ice. However, climate models differ in their representation of the freshwater sources. Recent improvements in altimetry-based detection of small icebergs and in estimates of the mass loss of Antarctica may help better constrain the values of Antarctic freshwater releases. We propose a model-based seasonal climatology of iceberg melt over the Southern Ocean using state-of-the-art observed glaciological estimates of the Antarctic mass loss. An improved version of a Lagrangian iceberg model is coupled with a global, eddy-permitting ocean/sea ice model and compared to small icebergs observations. Iceberg melt increases sea ice...
Tipo: Text
Palavras-chave: Icebergs; Southern Ocean; Sea ice; Freshwater fluxes.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00335/44579/44294.pdf

Observation-Based Trends of the Southern Ocean Carbon Sink
Provedor de dados: 5
Autores: Ritter, R.; Landschuetzer, P.; Gruber, N.; Fay, A. R.; Iida, Y.; Jones, S.; Nakaoka, S.; Park, G. -h.; Peylin, P.; Roedenbeck, C.; Rodgers, K. B.; Shutler, J. D.; Zeng, J.
The Southern Ocean (SO) carbon sink has strengthened substantially since the year 2000, following a decade of a weakening trend. However, the surface ocean pCO(2) data underlying this trend reversal are sparse, requiring a substantial amount of extrapolation to map the data. Here we use nine different pCO(2) mapping products to investigate the SO trends and their sensitivity to the mapping procedure. We find a robust temporal coherence for the entire SO, with eight of the nine products agreeing on the sign of the decadal trends, that is, a weakening CO2 sink trend in the 1990s (on average 0.22 0.24pgCyr(-1)decade(-1)), and a strengthening sink trend during the 2000s (-0.35 0.23pgCyr(-1)decade(-1)). Spatially, the multiproduct mean reveals rather uniform...
Tipo: Text
Palavras-chave: Southern Ocean; CO2; Observations; SOCOM; Trends; Carbon sink.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00662/77387/79013.pdf

High-latitude forcing of diatom productivity in the southern Agulhas Plateau during the past 350 kyr
Provedor de dados: 5
Autores: Romero, O. E.; Kim, J. -h.; Barcena, M. A.; Hall, I. R.; Zahn, R.; Schneider, R.
The hydrography of the Indian-Atlantic Ocean gateway has been connected to high-latitude climate dynamics by oceanic and atmospheric teleconnections on orbital and suborbital timescales. A wealth of sedimentary records aiming at reconstructing the late Pleistocene paleoceanography around the southern African continent has been devoted to understanding these linkages. Most of the records are, however, clustered close to the southern South African tip, with comparatively less attention devoted to areas under the direct influence of frontal zones of the Southern Ocean/South Atlantic. Here we present data of the composition and concentration of the diatom assemblage together with bulk biogenic content and the alkenone-based sea surface temperature (SST)...
Tipo: Text
Palavras-chave: Agulhas; SST; Diatoms; Fronts; Silica; Southern Ocean.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00294/40555/39440.pdf

Space and time variability of the Southern Ocean carbon budget
Provedor de dados: 5
Autores: Rosso, Isabella; Mazloff, Matthew R.; Verdy, Ariane; Talley, Lynne D.
The upper ocean dissolved inorganic carbon (DIC) concentration is regulated by advective and diffusive transport divergence, biological processes, freshwater, and air-sea CO2 fluxes. The relative importance of these mechanisms in the Southern Ocean is uncertain, as year-round observations in this area have been limited. We use a novel physical-biogeochemical state estimate of the Southern Ocean to construct a closed DIC budget of the top 650 m and investigate the spatial and temporal variability of the different components of the carbon system. The dominant mechanisms of variability in upper ocean DIC depend on location and time and space scales considered. Advective transport is the most influential mechanism and governs the local DIC budget across the 10...
Tipo: Text
Palavras-chave: Carbon budget; Southern Ocean; State estimate.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00662/77395/78996.pdf

Composition of diatom communities and their contribution to plankton biomass in the naturally iron fertilized region of Kerguelen in the Southern Ocean
Provedor de dados: 5
Autores: Lasbleiz, Marine; Leblanc, Karine; Armand, Leanne K.; Christaki, Urania; Georges, Clement; Obernosterer, Ingrid; Queguiner, Bernard.
In the naturally iron-fertilized surface waters of the northern Kerguelen Plateau region, the early spring diatom community composition and contribution to plankton carbon biomass were investigated and compared with the High Nutrient Low Chlorophyll (HNLC) surrounding waters. The large iron-induced blooms were dominated by small diatom species belonging to the genera Chaetoceros (Hyalochaete) and Thalassiosira, which rapidly responded to the onset of favorable light-conditions in the meander of the Polar Front. In comparison, the iron-limited HNLC area was typically characterized by autotrophic nanoeukaryote-dominated communities and by larger and more heavily silicified diatom species (e.g. Fragilariopsis spp.). Our results support the hypothesis that...
Tipo: Text
Palavras-chave: Diatoms; Carbon biomass; Plankton community structure; Natural iron fertilization; Southern Ocean.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00347/45850/45512.pdf

The role of zooplankton communities in carbon recycling in the Ocean: the case of the Southern Ocean
Provedor de dados: 5
Autores: Mayzaud, Patrick; Pakhomov, Evgeny A.
Basin-scale carbon recycling estimates were obtained by combining high-resolution data on zooplankton taxonomic and functional composition with species-specific respiration rates. Datasets were collected in the Atlantic and Indian sectors of the Southern Ocean during four cruises covering spring, mid-summer, autumn and late winter between 1993 and 1998. Carbon recycling by Antarctic meso-and macrozooplankton represented a significant (44-62%) fraction of the primary production, which is at the higher end of previous estimates. Assessment based on detailed community structure appeared to be more realistic than previous estimates and showed that carbon dioxide recycling at the global scale is not a mere function of temperature and abundance of zooplankton....
Tipo: Text
Palavras-chave: Zooplankton community; Carbon recycling; Southern Ocean.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00289/40060/38758.pdf

Contribution of resuspended sedimentary particles to dissolved iron and manganese in the ocean: An experimental study
Provedor de dados: 5
Autores: Cheize, Marie; Planquette, H.f.; Fitzsimmons, J.n.; Pelleter, Ewan; Sherrell, R.m.; Lambert, Christophe; Bucciarelli, E.; Sarthou, G.; Le Goff, Marion; Liorzou, Celine; Chéron, Sandrine; Viollier, E.; Gayet, Nicolas.
A number of trace metals play essential roles in marine ecosystem structure and biological productivity. Until recently, it has been argued that phytoplankton access primarily dissolved iron, while particulate iron was considered a refractory material with little use biologically and limited interaction with the dissolved pool. In order to assess the transfer mechanisms between sediment-sourced particulate trace metals and the dissolved pool, we conducted a 14-month incubation that reacted resuspended sediments with natural seawater, both originating from the Kerguelen area (KEOPS cruises; Southern Ocean), in the dark, and at concentrations replicating natural conditions. Three types of sediments were investigated (named BioSi, BioSi + Ca, and Basalt),...
Tipo: Text
Palavras-chave: Suspended particle dissolution; Sediment; Iron; Manganese; Biogenic silica; Southern Ocean; Kerguelen.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00460/57197/59166.pdf

Integrated assessment of the spatial distribution and structural dynamics of deep benthic marine communities
Provedor de dados: 5
Autores: Jansen, Jan; Dunstan, Piers K.; Hill, Nicole A.; Koubbi, Philippe; Melbourne‐thomas, Jessica; Causse, Romain; Johnson, Craig R.
Characterising the spatial distribution and variation of species communities and validating these characteristics with data from the field are key elements for an ecosystem‐based approach to management. However, models of species distributions that yield community structure are usually not linked to models of community dynamics, constraining understanding and management of the ecosystem, particularly in data‐poor regions. Here we use a qualitative network model to predict changes in Antarctic benthic community structure between major marine habitats characterised largely by seafloor depth and slope, and use multivariate mixture models of species distributions to validate the community dynamics. Further, we then assess how future increases in primary...
Tipo: Text
Palavras-chave: Deep‐sea; Ecosystem structure; Ecosystem dynamic; Southern Ocean; Antarctica; Continental shelf; Upper slope; Species archetype model; Qualitative network model; Spatial model.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00599/71143/69460.pdf

Interannual variability of the carbon dioxide system in the southern Indian Ocean (20 degrees S-60 degrees S): The impact of a warm anomaly in austral summer 1998
Provedor de dados: 5
Autores: Jabaud-jan, A; Metzl, N; Brunet, C; Poisson, A; Schauer, B.
The interannual variations of the carbon dioxide system and air-sea CO(2) fluxes are analyzed in the southwestern Indian Ocean from both in situ (Ocean Indien Service d'Observations cruises in 1998 and 2000) and simulated oceanic CO(2) fugacity f(CO2) dissolved inorganic carbon, total alkalinity, and nutrients. During austral summer of 1998, the ocean was warmer from 20degreesS to 60degreesS. In the Subtropical Zone (20degreesS-37degreesS), the warming, associated with the subtropical dipole pattern, creates an oceanic CO(2) source around 2 mmol m(-2) d(-1) in January 1998 where all previous observations, included in 2000, indicated that this region was a small sink in summer. In the Sub-Antarctic and Polar Front Zones (37degreesS-50degreesS), the f(CO2)...
Tipo: Text
Palavras-chave: Air-sea CO(2) fluxes; Southern Ocean; Seasonal and interannual variabilities; Warm anomaly.
Ano: 2004
URL: https://archimer.ifremer.fr/doc/00228/33919/32208.pdf

Écologie trophique des étoiles de mer de l’Océan Austral : Influence des facteurs environnementaux sur la diversité trophique
Provedor de dados: 5
Autores: Le Bourg, Baptiste.
Like in the rest of the world, climate change impacts the Southern Ocean, but not in the same way in all regions of this ocean. Changes in sea ice cover around the Antarctic continent are one of the most visible manifestations. For example, sea ice cover has decreased significantly in the Western Antarctic Peninsula while it tends to increase slightly on the rest of the coastline of the continent. These changes in environmental conditions influence the functioning of the ecosystems of this ocean. In particular, the disappearance or persistence of sea ice in a region where it was seasonally present may prevent the appearance of summer phytoplankton blooms, thus impacting the dynamics of krill populations and their predators in the pelagic environment. The...
Tipo: Text
Palavras-chave: Sea stars; Southern Ocean; Trophic ecology; Stable isotopes.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00633/74468/74296.pdf

Ice wastage on the Kerguelen Islands (49 degrees S, 69 degrees E) between 1963 and 2006
Provedor de dados: 5
Autores: Berthier, Etienne; Le Bris, Raymond; Mabileau, Laure; Testut, Laurent; Remy, Frederique.
We observed the wastage of ice masses on the Kerguelen Islands ( Indian Ocean, 49 degrees S, 69 degrees E) using historical information and recent satellite data. Overall, the total ice-covered area on the islands declined from 703 to 552 km(2) between 1963 and 2001, a reduction of 21%. The area of Cook ice cap ( the main ice body) decreased asymmetrically from 501 to 403 km(2). West flowing glaciers lost 11% of their area, while east flowing glaciers lost 28%. After 1991, the retreat rate accelerated from 1.9 km(2)/a ( 1963-1991) to 3.8 km(2)/a ( 1991-2003). Between 1963 and 2000, the ice volume loss was 25-30 km(3), equivalent to an area-average ice-thinning rate of 1.4-1.7 m/a. The glacial retreat took place in the climatic context of a relatively low...
Tipo: Text
Palavras-chave: Ice caps; Climate change; Remote sensing; Kerguelen Islands; Southern Ocean; Mass balance.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00219/33069/31557.pdf

On the distribution of silicic acid as a frontal zone tracer in the Indian sector of the Southern Ocean
Provedor de dados: 5
Autores: Prego, R; Park, Yh; Barciela, Mc; Morvan, J; Poncin, J; Treguer, P.
The subantarctic frontal zone surveyed during the April-May 1991 SUZIL cruise in the Crozet-Kerguelen Amsterdam area shows a strong horizontal (north to south) gradient of dissolved silicate, increasing with depth, from 5 to 10 mu molSi kg(-1) at 100 m, and 10 to 70 mu molSi kg(-1) at 600 m. The northern limit of this frontal zone, which is formed by the confluence of the Subtropical and Subantarctic Fronts, is delimited at the surface by the 2 mu molSi kg(-1) silicate isoline. Silicate-salinity diagrams also allow different water regimes to be positioned relative to the frontal zone. This sloping interface is between two water bodies, one to the north with more saline subtropical waters of less concentrated silicate than the southern one, corresponding to...
Tipo: Text
Palavras-chave: Silicate; Tracer; Frontal zone; Silicate-salinity diagram; Crozet Basin; Southern Ocean.
Ano: 1999
URL: https://archimer.ifremer.fr/doc/00239/35063/34593.pdf

Seasonally different carbon flux changes in the Southern Ocean in response to the southern annular mode
Provedor de dados: 5
Autores: Hauck, J.; Voelker, C.; Wang, T.; Hoppema, M.; Losch, M.; Wolf-gladrow, D. A.
Stratospheric ozone depletion and emission of greenhouse gases lead to a trend of the southern annular mode (SAM) toward its high-index polarity. The positive phase of the SAM is characterized by stronger than usual westerly winds that induce changes in the physical carbon transport. Changes in the natural carbon budget of the upper 100 m of the Southern Ocean in response to a positive SAM phase are explored with a coupled ecosystem-general circulation model and regression analysis. Previously overlooked processes that are important for the upper ocean carbon budget during a positive SAM period are identified, namely, export production and downward transport of carbon north of the polar front (PF) as large as the upwelling in the south. The limiting...
Tipo: Text
Palavras-chave: Southern Ocean; Southern annular mode; Carbon cycle; Carbon sink.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00292/40352/38988.pdf

Response of sea surface fugacity of CO2 to the SAM shift south of Tasmania: Regional differences
Provedor de dados: 5
Autores: Xue, Liang; Gao, Libao; Cai, Wei-jun; Yu, Weidong; Wei, Meng.
Using observational data collected south of Tasmania during 14 austral summer cruises during 1993-2011, we examined the response of sea surface fugacity of carbon dioxide (fCO(2)) to the Southern Annular Mode (SAM) shift, which occurred around 2000. In the southern part of the Southern Ocean (SO) or the Polar Zone (PZ) and the Polar Frontal Zone (PFZ), fCO(2) increased faster at the sea surface than in the atmosphere before the SAM shift, but not after the shift. In the northern part of the SO or the Subantarctic Zone (SAZ), however, surface fCO(2) increased faster than atmospheric fCO(2) both before and after the shift. The SAM shift had an important influence on the surface fCO(2) trend in the PZ and PFZ but not in the SAZ, which we attribute to...
Tipo: Text
Palavras-chave: Southern Ocean; Southern Annular Mode shift; Carbon cycling; Upwelling; South of Tasmania.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00292/40369/38947.pdf

Particle flux characterisation and sedimentation patterns of protistan plankton during the iron fertilisation experiment LOHAFEX in the Southern Ocean
Provedor de dados: 5
Autores: Ebersbach, Friederike; Assmy, Philipp; Martin, Patrick; Schulz, Isabelle; Wolzenburg, Sina; Noethig, Eva-maria.
The taxonomic composition and types of particles comprising the downward particle flux were examined during the mesoscale artificial iron fertilisation experiment LOHAFEX. The experiment was conducted in low-silicate waters of the Atlantic Sector of the Southern Ocean during austral summer (January-March 2009), and induced a bloom dominated by small flagellates. Downward particle flux was low throughout the experiment, and not enhanced by addition of iron; neutrally buoyant sediment traps contained mostly faecal pellets and faecal material apparently reprocessed by mesozooplankton. TEP fluxes were low, &lt;= 5 mg GX eq. m(-2) d(-1), and a few phytodetrital aggregates were found in the sediment traps. Only a few per cent of the POC flux was found in the...
Tipo: Text
Palavras-chave: Nano- and picoplankton; Export flux; Iron fertilisation; Protists; Sediment trap; Southern Ocean.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00290/40121/39348.pdf

Stable isotopes reveal the trophic position and mesopelagic fish diet of female southern elephant seals breeding on the Kerguelen Islands
Provedor de dados: 5
Autores: Cherel, Y; Ducatez, S; Fontaine, C; Richard, Patrice; Guinet, C.
Trophic interactions between organisms are the main drivers of ecosystem dynamics, but scant dietary information is available for wide-ranging predators during migration. We investigated feeding habits of a key consumer of the Southern Ocean, the southern elephant seal Miroungia leonina, by comparing its blood delta(13) C and delta N-15 values with those of various marine organisms, including crustaceans, squid, fishes, seabirds and fur seals. At the end of winter, delta C-13 values (-23.1 to -20.1 parts per thousand)indicate that female elephant seals forage mainly in the vicinity of the Polar Front and in the Polar Frontal Zone. Trophic levels derived from delta N-15 values (trophic level = 4.6) show that the southern elephant seal is a top consumer in...
Tipo: Text
Palavras-chave: Squid; Southern Ocean; Pelagic ecosystem; Myctophid; Mesopelagic fish; Cephalopod.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/publication-5021.pdf

Deep temperature variability in Drake Passage
Provedor de dados: 5
Autores: Firing, Yvonne L.; Mcdonagh, Elaine L.; King, Brian A.; Desbruyeres, Damien.
Observations made on 21 occupations between 1993 and 2016 of GO-SHIP line SR1b in eastern Drake Passage show an average temperature of 0.53 degrees C deeper than 2000 dbar, with no significant trend, but substantial year-to-year variability (standard deviation 0.08 degrees C). Using a neutral density framework to decompose the temperature variability into isopycnal displacement (heave) and isopycnal property change components shows that approximately 95% of the year-to-year variance in deep temperature is due to heave. Changes on isopycnals make a small contribution to year-to-year variability but contribute a significant trend of -1.40.6 m degrees C per year, largest for density ((n))&gt;28.1, south of the Polar Front (PF). The heave component is...
Tipo: Text
Palavras-chave: Temperature; Trends; Southern Ocean.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00387/49812/50390.pdf

Ultraviolet radiation induces reversal of the bioavailability of DOM to marine bacterioplankton
Provedor de dados: 5
Autores: Obernosterer, I; Sempere, R; Herndl, Gj.
2-fold higher in the &lt;20 kDa fraction than in the bulk DOM. These results clearly indicate that initially bioreactive DOM can be rendered biologically more recalcitrant by exposure to solar radiation, while DOM of initially low bioavailability can be, at least partly, photochemically transformed to compounds of higher biological reactivity.
Tipo: Text
Palavras-chave: Dissolved organic matter; Ultraviolet radiation; DOM-photoreactivity; Bacterioplankton; Southern Ocean.
Ano: 2001
URL: https://archimer.ifremer.fr/doc/00220/33170/31686.pdf

Etude de l'impact des icebergs Antarctiques sur l'Océan Austral
Provedor de dados: 5
Autores: Bouhier, Nicolas.
The Antarctic polar ice cap constrains a freshwater flaux into the Austral Ocean through two equally important pathways : a localized and immediate injection through the melting of ice-shelves bases, and a delayed offshore injection through the calving and subsequent melt of icebergs. Some studies reckon that melting icebergs have the capacity to alter the hydrological and biogeo-chemical characteristics of the water column. The numerical models trying to evaluate this impact have shown contrasting results. Yet, they might suffer from a poor representation of the icebergs, namely due to our limited knowledge on both the spatial and size distributions of the icebergs, or even the processes involved in their mass loss. A new method using satellite altimetry...
Tipo: Text
Palavras-chave: Ntarctique; Calotte polaire; Plate-forme glaciaire; Océan austral; Flux d’eau douce; Télédétection; Banquise; Fonte; Fracturation; Distribution de taille; Antarctica; Ice cap; Ice shelf; Southern Ocean; Iceberg; Freshwater flux; Remote sensing; Sea ice; Melting; Fragmentation; Fracturing; Size distribution.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00497/60905/64253.pdf

Circumpolar dataset of sequenced specimens of Promachocrinus kerguelensis (Echinodermata, Crinoidea)
Provedor de dados: 5
Autores: Hemery, Lenaig G.; Ameziane, Nadia; Eleaume, Marc.
This circumpolar dataset of the comatulid (Echinodermata: Crinoidea) Promachocrinus kerguelensis (Carpenter, 1888) from the Southern Ocean, documents biodiversity associated with the specimens sequenced in Hemery et al. (2012). The aim of Hemery et al. (2012) paper was to use phylogeographic and phylogenetic tools to assess the genetic diversity, demographic history and evolutionary relationships of this very common and abundant comatulid, in the context of the glacial history of the Antarctic and Sub-Antarctic shelves (Thatje et al. 2005, 2008). Over one thousand three hundred specimens (1307) used in this study were collected during seventeen cruises from 1996 to 2010, in eight regions of the Southern Ocean: Kerguelen Plateau, Davis Sea, Dumont d'Urville...
Tipo: Text
Palavras-chave: Antarctica; Crinoidea; Cytochrome Oxydase subunit I; Echinodermata; Phylogeography; Promachocrinus; Southern Ocean; Sub-Antarctic.
Ano: 2013
URL: https://archimer.ifremer.fr/doc/00296/40758/39749.pdf

Large-scale distribution analysis of Antarctic echinoids using ecological niche modelling
Provedor de dados: 5
Autores: Pierrat, Benjamin; Saucede, Thomas; Laffont, Remi; De Ridder, Chantal; Festeau, Alain; David, Bruno.
Understanding the factors that determine the distribution of taxa at various spatial scales is a crucial challenge in the context of global climate change. This holds particularly true for polar marine biota that are composed of both highly adapted and vulnerable faunas. We analysed the distribution of 2 Antarctic echinoid species, Sterechinus antarcticus and S. neumayeri, at the scale of the entire Southern Ocean using 2 niche modelling procedures. The performance of distribution models was tested with regard to the known ecology of the species. The respective contributions of environmental parameters are discussed along with the putative roles played by biotic interactions and biogeographic processes. Depth was the parameter that contributed most to both...
Tipo: Text
Palavras-chave: Habitat suitability map; Sterechinus; Echinoidea; GARP; Maxent; Southern Ocean.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00296/40764/39774.pdf

Echinoids of the Kerguelen Plateau – occurrence data and environmental setting for past, present, and future species distribution modelling
Provedor de dados: 5
Autores: Guillaumot, Charlene; Martin, Alexis; Fabri-ruiz, Salome; Eleaume, Marc; Saucede, Thomas.
The present dataset provides a case study for species distribution modelling (SDM) and for model testing in a poorly documented marine region.  The dataset includes spatially-explicit data for echinoid (Echinodermata: Echinoidea) distribution. Echinoids were collected during oceanographic campaigns led around the Kerguelen Plateau (+63°/+81°E; -46°/-56°S) since 1872. In addition to the identification of collection specimens from historical cruises, original data from the recent campaigns POKER II (2010) and PROTEKER 2 to 4 (2013-2015) are also provided. In total, five families, ten genera, and 12 echinoid species are recorded in the region of the Kerguelen Plateau.  The dataset is complemented with environmental descriptors available and relevant for...
Tipo: Text
Palavras-chave: Echinoidea; Environmental descriptors; Future projections; Historical overview; Kerguelen Plateau; Southern Ocean.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00357/46829/46700.pdf

Mesoscale modulation of air-sea CO2 flux in Drake Passage
Provedor de dados: 5
Autores: Song, Hajoon; Marshall, John; Munro, David R.; Dutkiewicz, Stephanie; Sweeney, Colm; Mcgillicuddy, D. J., Jr.; Hausmann, Ute.
We investigate the role of mesoscale eddies in modulating air-sea CO2 flux and associated biogeochemical fields in Drake Passage using in situ observations and an eddy-resolving numerical model. Both observations and model show a negative correlation between temperature and partial pressure of CO2 (pCO(2)) anomalies at the sea surface in austral summer, indicating that warm/cold anticyclonic/cyclonic eddies take up more/less CO2. In austral winter, in contrast, relationships are reversed: warm/cold anticyclonic/cyclonic eddies are characterized by a positive/negative pCO(2) anomaly and more/less CO2 outgassing. It is argued that DIC-driven effects on pCO(2) are greater than temperature effects in austral summer, leading to a negative correlation. In...
Tipo: Text
Palavras-chave: CO2 flux; Mesoscale eddy; Southern Ocean; Vertical mixing; Nutrient fluxes.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00383/49407/49894.pdf

The last five glacial-interglacial transitions: A high-resolution 450,000-year record from the subantarctic Atlantic
Provedor de dados: 5
Autores: Cortese, G.; Abelmann, A.; Gersonde, R.
A submillennial resolution, radiolarian-based record of summer sea surface temperature (SST) documents the last five glacial to interglacial transitions at the subtropical front, southern Atlantic Ocean. Rapid fluctuations occur both during glacial and interglacial intervals, and sudden cooling episodes at glacial terminations are recurrent. Surface hydrography and global ice volume proxies from the same core suggest that summer SST increases prior to terminations lead global ice- volume decreases by 4.7 +/- 3.7 ka (in the eccentricity band), 6.9 +/- 2.5 ka (obliquity), and 2.7 +/- 0.9 ka (precession). A comparison between SST and benthic delta C-13 suggests a decoupling in the response of northern subantarctic surface, intermediate, and deep water masses...
Tipo: Text
Palavras-chave: Paleotemperature; Radiolaria; Southern Ocean.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00236/34725/33297.pdf

Sphaeromatidae (Crustacea, Isopoda) of the Beagle Channel and description of Cymodopsis beageli n. sp
Provedor de dados: 16
Autores: Brandt, Angelina.
During an expedition with RV Victor Hensen (1994) and the RV Polarstern (1996) Isopoda Sphaeromatidae were collected in and off the eastern entrance of the Beagle Channel. The species found, Caecocassidias patagonica Kussakin, 1967, Cassidinopsis emarginata (Guérin-Méneville, 1843) and Moruloidea darwinii (Cunningham, 1871), were previously all poorly or insufficiently described; therefore a redescription is presented herein. Exosphaeroma gigas (Leach, 1818) was also collected frequently, but it was already redescribed earlier and thus only the localities are presented. Moreover, a new species, Cymodopsis beageli, n.sp., which is most closely allied to Cymodopsis sphyracephalata Hurley &amp; Janssen, 1977, is described from the Beagle Channel.
Tipo: Article / Letter to the editor
Palavras-chave: Crustacea; Isopoda; Taxonomy; Beagle Channel; South America; Southern Ocean; Subantarctic.
Ano: 1998
URL: http://www.repository.naturalis.nl/record/504937

Short notes and reviews A Storthyngura (Crustacea, Isopoda) from the Bellingshausen Sea, Antarctica
Provedor de dados: 16
Autores: Brandt, Angelika.
During the expedition ANT XI/3 with RV Polarstern 17 multiple corers were taken in the Bellingshausen Sea. From this material only a single, immature isopod was sorted. This specimen is a manca II of a presumably new species of the genus Storthyngura. However, as it is immature and only a single specimen was sampled, more material of this species will have to be collected prior to the description of a new species.
Tipo: Article / Letter to the editor
Palavras-chave: Southern Ocean; Bellingshausen Sea; Isopoda; Storthyngura.
Ano: 2000
URL: http://www.repository.naturalis.nl/record/534345

Monstrilloida (Crustacea: Copepoda) from the Beagle Channel, South America
Provedor de dados: 16
Autores: Suárez-Morales, E.; Ramírez, F.C.; Derisio, C.
Monstrilloid copepods were collected during zooplankton surveys in the Beagle Channel at the southernmost end of South America. These specimens represent two species of Monstrillopsis, one of them undescribed, and one new species of Monstrilla. Monstrillopsis igniterra n. sp. is related to forms of the M. dubia species group, and particularly to M. ferrarii and M. chilensis. It differs from these species in the relative length of the antennules, the shape and relative size of the genital double and anal somites, details of the antennular armature, and the possession of a short inner caudal seta. The other species of Monstrillopsis, M. chilensis, was previously known only from the Southeast Pacific off Chile, and was originally described from female...
Tipo: Article / Letter to the editor
Palavras-chave: Associated copepoda; Marine zooplankton; Southern Ocean; Taxonomy; 42.74.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/291893

Two new species of Protomyctophum (Pisces, Teleostei, Myctophidae) from the Southern Ocean
Provedor de dados: 16
Autores: Prokofiev, Artém M.
Two new species of the genus Protomyctophum from the Southern Ocean are described. P. mcginnisi n. sp. (from off the Southern Shetland Islands) is most closely related to P. bolini (Fraser-Brunner, 1949), from which it differs in photophore arrangement, in metallic shine of the photophores, and in higher number of gill-rakers on the first gill arch. P. kolaevi n. sp. (from off the Balleny Islands) is most closely related to P. tenisoni (Norman, 1930) and especially to P. choriodon Hulley, 1981, but differs from both these species by its much wider interorbital space, and in photophore arrangement. A key to the species of Protomyctophum known south of the subtropic convergence is included.
Tipo: Article / Letter to the editor
Palavras-chave: Lanternfishes; Protomyctophum; New species; Key of species; Southern Ocean.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/505219

On suspended barite and the oxygen minimum in the Southern Ocean
Provedor de dados: 27
Autores: Dehairs, F.A.; Goeyens, L.; Stroobants, N.; Bernard, P.; Goyet, C.; Poisson, A.; Chesselet, R.
Particulate Ba profiles were measured in the Indian sector of the southern ocean. The largest fraction (&gt;80%) of this barium is present as barite microcrystals. The profiles of total barium are characterized by a subsurface maximum between 200 and 500 m depth in the vicinity of the oxygen minimum. Highest barium values are found just south of the Polar Front, while lowest values occur close to the Antarctic Divergence. Between the divergence and the Polar front a tight inverse relationship is observed between oxygen in the oxygen minimum and barium in the barium maximum. This relationship disappears north of the Polar Front. Since suspended barite is known to be of biological origin, the correlation of barite with oxygen suggests that the observed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Barite Oxygen PS; Southern Ocean.
Ano: 1990
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3076

Contribution to the marine biodiversity inventory: a checklist of the Amphipoda (Crustacea) of the Southern Ocean
Provedor de dados: 27
Autores: De Broyer, C.; Jazdzewski, K.
A checklist, with synonymical bibliography, of all benthic, supralittoral and pelagic Amphipoda (Gammaridea, Caprellidea and Hyperiidea) occurring in the Southern Ocean is drawn up, mostly from taxonomical literature checked until 31 December 1992. 883 taxa have been recorded: 711 spp. and subspp. of Gammaridea, 28 spp. of Caprellidea, 69 spp. and subspp. of Hyperiidea as well as 75 unidentified spp. (73 Gammaridea, 2 Caprellidea). Distribution in the East or West Antarctic sub-regions, in the Subantarctic Islands sub-region, in the Magellanic sub-region and in the Tristan da Cunha district is mentioned. Bathyal and abyssal benthic occurrence is indicated as well as the general bathymetrical distribution of the pelagic species occurring south of 45°S. The...
Tipo: Info:eu-repo/semantics/book
Palavras-chave: Amphipoda [amphipods] PS; Southern Ocean.
Ano: 1993
URL: http://www.vliz.be/imisdocs/publications/251879.pdf

Effects of UV on photosynthesis of Antarctic phytoplankton: models and their application to coastal and pelagic assemblages
Provedor de dados: 97
Autores: NEALE,PATRICK J.; FRITZ,JENNIFER J.; DAVIS,RICHARD F.
We have characterized the photosynthetic response to ultraviolet radiation (UV) of natural phytoplankton assemblages in Antarctic (Southern Ocean) waters. Biological weighting functions (BWFs) and exposure response curves for inhibition of photosynthesis by UV were measured during spring-time ozone depletion (October-November). Two different models were developed to relate photosynthesis to UV exposure. A model that is a function of the duration of exposure (BWF H) applied to assemblages in the well-mixed open waters of the Weddell-Scotia Confluence (WSC, 60° S, 50° W), since responses were a function of cumulative exposure and recovery rates were slow. These assemblages had a variable but generally high sensitivity to UV. A steady-state model (BWF E)...
Tipo: Journal article
Palavras-chave: Southern Ocean; Primary productivity; Ozone depletion; Photosynthesis-irradiance curves; Biological weighting functions.
Ano: 2001
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000200006

Restricted geographic distribution and low genetic diversity of the brooding sea urchin Abatus agassizii (Spatangoidea: Schizasteridae) in the South Shetland Islands: A bridgehead population before the spread to the northern Antarctic Peninsula?
Provedor de dados: 97
Autores: DÍAZ,ANGIE; GONZÁLEZ-WEVAR,CLAUDIO ALEJANDRO; MATURANA,CLAUDIA S; PALMA,ALVARO T; POULIN,ELIE; GERARD,KARIN.
The glacial cycles of the Pleistocene have promoted the principal climatic changes of the Southern Ocean, and motivated scientific interest regarding the strategies developed by marine benthic invertebrates to tolerate and overcome the extension and contraction of the ice sheet on the Antarctic continental platform. A recent study of the bathymetric zonation and distribution of macro-invertebrates in a shallow subtidal area of Fildes Bay (King George Island, South Shetlands Islands, Antarctica) highlighted the presence of a large aggregation of the brooding sea urchin Abatus agassizii, whose geographic distribution is known only for localities south of the Antarctic convergence (Antarctic Peninsula and South Shetland and South Georgia Islands in the Scotia...
Tipo: Journal article
Palavras-chave: Antarctic benthic fauna; COI phylogenetic relationships; King George Island; Southern Ocean; Survivor population.
Ano: 2012
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2012000400008