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| 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 |
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| Castaneda, Isla S.; Caley, Thibaut; Dupont, Lydie; Kim, Jung-hyun; Malaize, Bruno; Schouten, Stefan. |
| In this study we investigate Pleistocene vegetation and climate change in southern East Africa by examining plant leaf waxes in a marine sediment core that receives terrestrial runoff from the Limpopo River. The plant leaf wax records are compared to a multi-proxy sea surface temperature (SST) record and pollen assemblage data from the same site. We find that Indian Ocean SST variability, driven by high-latitude obliquity, exerted a strong control on the vegetation of southern East Africa during the past 800,000 yr. Interglacial periods were characterized by relatively wetter and warmer conditions, increased contributions of C3 vegetation, and higher SST, whereas glacial periods were marked by cooler and arid conditions, increased contributions of C4... |
| Tipo: Text |
Palavras-chave: Vegetation; Africa; N-alkane; Pollen; Subtropical Front; Mid-Brunhes. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00345/45601/45215.pdf |
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| 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 |
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