Mid-Pleistocene benthic foraminifera of Southwestern South Atlantic: driven by primary productivity or water masses properties?

GARCÍA CHAPORI, N., LAPRIDA, C., VIOLANTE, R., WATANABE, S. AND TOTAH, V.

MICROPALEONTOLOGY

MICROPALEONTOLOGY PRESS

Lugar: New York; Año: 2012

0026-2803

The Southwestern South Atlantic represents a region of crucial water exchange between the Southern Ocean and the subtropical basins where several water masses have been identified. On the sea surface, the area presents a highly dynamic frontal zone and exhibits large spatial and temporal variability in primary productivity that influences the export of organic carbon from the euphotic zone. In some areas of the Southern Ocean, benthic foraminiferal faunal changes have been interpreted as changes in deep water-masses distribution or changes in surface productivity. In order to define the main factor controlling the species composition during a glacial Mid-Pleistocene event (MIS 6 or 8), productivity and water masses markers from core SP1251 (3400 m; ~38°S - 54°W) were studied. Their distribution was analyzed and interpreted considering previous hydrographical reconstructions. Our results indicate that in the glacial Mid-Pleistocene Southwestern South Atlantic surface primary productivity was the main factor determining the benthic foraminiferal assemblage composition. Primary productivity regime was not uniform as a result of climatically related changes in Antarctic upwelling.