Ten Years of Paleoceanographic Studies at ODP Site 963 (Central Mediterranean Sea)

Abstract

The geographical location, the shape and the circulation pattern makes the Mediterranean Sea an ideal laboratory to study the interplay between different climatic systems, abrupt climate changes and the response of marine ecosystems. The Ocean Drilling Program Site 963 was drilled in the Northwestern part of the Sicily Channel, the sill that divides the western from the eastern Mediterranean Sea. Numerous papers have been published on Site 963 sediments in the last decade, investigating Mediterranean paleoceanographic themes. Here we offer a synthetic framework of these investigations carried out by sub-centennial resolution. We present the whole sequence of suborbital climatic oscillations over the last 130 kyr, that is since the last interglacial period, and we claim that teleconnection with Greenland and North Atlantic regions is the most likely phenomenon to explain our results. Furthermore we show the high sensitivity of marine planktonic (planktonic foraminifera and coccolithophores) ecosystems to Stadial/Interstadial fluctuations. We conclude that a three-steps scenario may describe productivity variations during each high-frequency oscillation, from Interstadial 24 to the last deglaciation (from 110 to 15 kiloyears ago): surface oligotrophy and a deep nutricline in the lower part of Interstadials; increased productivity, through a deep chlorophyll maximum and winter/spring coccolithophore blooms, during the upper part of Interstadials; a shallow nutricline during Stadials and possibly reduced productivity levels with respect to the upper Interstadial phase. Results from Site 963 investigations provide key information for very high-resolution paleoceanographic research in the Mediterranean Sea.