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| Wallmann, K.; Schneider, B.; Sarnthein, M.. |
| We have developed and employed an Earth system model to explore the forcings of atmospheric pCO(2) change and the chemical and isotopic evolution of seawater over the last glacial cycle. Concentrations of dissolved phosphorus (DP), reactive nitrogen, molecular oxygen, dissolved inorganic carbon (DIC), total alkalinity (TA), C-13-DIC, and C-14-DIC were calculated for 24 ocean boxes. The bi-directional water fluxes between these model boxes were derived from a 3-D circulation field of the modern ocean (Opa 8.2, NEMO) and tuned such that tracer distributions calculated by the box model were consistent with observational data from the modern ocean. To model the last 130 kyr, we employed records of past changes in sea-level, ocean circulation, and dust... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00496/60800/64806.pdf |
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| Sarnthein, M.; Schneider, B.; Grootes, P. M.. |
| Ice core records demonstrate a glacial-interglacial atmospheric CO2 increase of ~ 100 ppm. A transfer of ~ 530 Gt C is required to produce the deglacial rise of carbon in the atmosphere and terrestrial biosphere. This amount is usually ascribed to oceanic carbon release, although the actual mechanisms remained elusive, since an adequately old and carbon-enriched deep-ocean reservoir seemed unlikely. Here we present a new, though still fragmentary, ocean-wide 14C dataset showing that during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS-1) the 14C age difference between ocean deep waters and the atmosphere exceeded the modern values by up to 1500 14C yr, in the extreme reaching 5100 yr. Below 2000 m depth the 14C ventilation age of modern ocean... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00296/40676/39662.pdf |
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| Sarnthein, M.; Schneider, B.; Grootes, P. M.. |
| Ice core records demonstrate a glacial-interglacial atmospheric CO2 increase of similar to 100 ppm, while C-14 calibration efforts document a strong decrease in atmospheric C-14 concentration during this period. A calculated transfer of similar to 530 Gt of C-14-depleted carbon is required to produce the deglacial coeval rise of carbon in the atmosphere and terrestrial biosphere. This amount is usually ascribed to oceanic carbon release, although the actual mechanisms remained elusive, since an adequately old and carbon-enriched deep-ocean reservoir seemed unlikely. Here we present a new, though still fragmentary, ocean-wide Delta C-14 data set showing that during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS-1) the maximum C-14 age difference... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00181/29237/27639.pdf |
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| Kissel, C.; Sarnthein, M.; Laj, C.; Wang, P. X.; Wandres, C.; Egli, R.. |
| More than 650 million tons/year of fluvial sediment are delivered from continental regions into the South China Sea (SCS). Previous studies have shown that the composition of the magnetic fraction of riverine sediments drained into the SCS is significantly variable from north to south. On the basis of this evidence, we now examine a full set of magnetic properties for a number of core‐tops taken at water depth comprised mostly between 800 and 3500 m. Room‐temperature magnetic parameters and thermal spectra are used to obtain information about the concentration and mineralogical magnetic composition. Spatial changes are observed in the relative proportion of magnetite and hematite with an increase of the latter toward the south, similarly to the observation... |
| Tipo: Text |
Palavras-chave: South China Sea; Magnetic mineralogy; Marine sediments. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00443/55502/57048.pdf |
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