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| Pichat, S; Sims, Kww; Francois, R; Mcmanus, Jf; Leger, Sb; Albarede, F. |
| The (Pa-231/Th-230)(xs,0) records obtained from two cores from the western (MD97-2138; 1degrees25'S, 146degrees24'E, 1900 m) and eastern (Ocean Drilling Program Leg 138 Site 849, 0degrees11.59'N, 110degrees31.18'W, 3851 m) equatorial Pacific display similar variability over the last 85,000 years, i.e., from isotopic stages 1 to 5a, with systematically higher values during the Holocene, isotopic stage 3, and isotopic stage 5a, and lower values, approaching the production rate ratio of the two isotopes (0.093), during the colder periods corresponding to isotopic stages 2 and 4. We have also measured the Th-230-normalized biogenic preserved and terrigenous fluxes, as well as major and trace elements concentrations, in both cores. The (Pa-231/Th-230)(xs,0)... |
| Tipo: Text |
Palavras-chave: (Pa-231/Th-230)(xs; 0) export productivity Pacific. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00228/33933/32240.pdf |
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| Trull, Tw; Bray, Sg; Manganini, Sj; Honjo, S; Francois, R. |
| Sediment trap moorings were deployed from September 21, 1997 through February 21, 1998 at three locations south of Australia along 140degreesE: at similar to47degreesS in the central Subantarctic Zone (SAZ) with traps at 1060, 2050, and 3850 m depth, at similar to51degreesS in the Subantarctic Front with one trap at 3080 m, and at similar to54degreesS in the Polar Frontal Zone (PFZ) with traps at 830 and 1580 m. Particle fluxes were high at all the sites (18-32 g m(-2) yr(-1) total mass and 0.5-1.4 g organic carbon m(-2) yr(-1) at similar to1000 m, assuming minimal flux outside the sampled summer period). These values are similar to other Southern Ocean results and to the median estimated for the global ocean by Lampitt and Antia [1997], and emphasize that... |
| Tipo: Text |
Palavras-chave: Carbon cycling; Global Change: Biogeochemical processes; Oceanography: Biological and Chemical: Biogeochemical cycles; Oceanography: General. |
| Ano: 2001 |
URL: https://archimer.ifremer.fr/doc/00221/33211/31697.pdf |
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| Sigman, Dm; Altabet, Ma; Francois, R; Mccorkle, Dc; Gaillard, Jf. |
| Treatment of diatom microfossils from Southern Ocean sediments with hot perchloric acid leaves a "diatom-bound" N fraction which is 0-4 parts per thousand lower in delta(15)N than the bulk sediment, typically 3 parts per thousand lower in recent Antarctic diatom ooze. Results from Southern Ocean surface sediments indicate that early diagenetic changes in bulk sediment N content and delta(15)N are not reflected in diatom-bound N, suggesting that diatom-bound N is physically protected from early diagenesis by the microfossil matrix. A meridional transect of multicores from the Indian sector of the Southern Ocean shows a northward increase in the delta(15)N Of diatom-bound N, suggesting that diatom-bound delta(15)N, like bulk sedimentary delta(15)N, varies... |
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| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35065/34591.pdf |
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