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| Registros recuperados: 86 | |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 (>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 (<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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| 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 |
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| Registros recuperados: 86 | |
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