Productivity modes in the mediterranean sea during dansgaard-oeschger (20,000-70,000yr ago) oscillations

Abstract

The study of planktonic organisms during abrupt climatic variations of the last glacial period (Dansgaard-Oeschger oscillations, D-O) may reveal important insights on climatic, oceanographic and biological interactions. Here we present planktic foraminifera and coccolithophore data collected at the Ocean Drilling Program Site 963 (Sicily Channel), with a mean sampling resolution of respectively 43.5 and 98.9. yr, over the interval between 70,000 and 20,000. yr ago. The paleoenvironmental reconstruction suggests that three different scenarios can be seen across each D-O cycle: 1. oligotrophic surface water and a deep thermocline for the early Interstadials; 2. a Deep Chlorophyll Maximum and coccolithophore winter/spring blooming in the late Interstadials; 3. reduced productivity together with the shallowing of the nutricline depth during Stadials and Heinrich events. The unique mode of productivity dynamics is corroborated by comparing our paleoecological results with those published fr...