Reconstitution of Biogenic Particle Flux in the Indian Sector of the Southern Ocean During the Last 140 Kyrs Deduced from 230Th Profiles in Sediment Cores

Ice core records show that the atmospheric concentration of carbon dioxide decreased during past glacial periods (Barnola et al., 1987). Southern Ocean seems to be a key area to explain these Isotopic stage I 2 observations. Series of papers attributed the glacial lowering of atmospheric C O 2 either to enhanced MD94102 T.z 'biological pump' or to a change in oceanic i,o 0.8 circulation (Broeker et al., 1986). However, estimates of past changes in Southern Ocean produc~ 0.6 tivity are still discussed, In order to answer this ~ 0.4 problem, we have chosen to study spatial and o.2 temporal variations of the biogenic particle flux in 0.0 the Indian sector of the Southern Ocean deduced MD88769 from 23~ profiles in sediment cores. ~.2