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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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Cardinal, D; Alleman, Ly; Dehairs, F; Savoye, N; Trull, Tw; Andre, L. |
We analyzed delta(29) Si of dissolved silicate for eight water column profiles across the Southern Ocean ( south of Australia in spring 2001) from the Seasonal Ice Zone (SIZ) north to the Subantarctic Zone (SAZ), including the first isotopic compositions measured for Si-depleted seawaters. All profiles display mixed layer enrichments in heavy Si isotopes relative to deep water in accordance with preferential uptake of the light isotope by diatoms. As silicate levels decrease from the SIZ northward across the Polar Front Zone (PFZ) to the SAZ, surface and mesopelagic delta(29) Si signatures generally become progressively heavier, but the most Si-depleted SAZ waters do not exhibit delta(29) Si values heavier than in the PFZ. This intricacy appears to derive... |
Tipo: Text |
Palavras-chave: Δ29Si; Δ30Si; Diatoms; Spring Southern Ocean; Fractionation factor. |
Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00233/34424/32838.pdf |
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