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

Abstract

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 highresolution paleoceanographic research in the Mediterranean Sea.

Offset timing of climate oscillations during the last two glacial‐interglacial transitions connected with large‐scale freshwater perturbation

“…This impacted the temperature and moisture gradients across the Mediterranean with consequences for the water exchange between the Mediterranean and the North Atlantic [ Cacho et al , ; Rogerson et al , ; Rodrigo‐Gámiz et al , ]. The combined influence of these changes impacted the Mediterranean marine system in its entirety including perturbations of the vertical stratification and trophic levels, ecosystems, and the thermohaline circulation at large [ Sierro et al , ; Incarbona et al , ; Sprovieri et al , ; Di Stefano et al , , ]. Comparison with pollen sequences [ Gasse and Van Campo , ; deMenocal and Baker , ; Combourieu‐Nebout et al , ; Sánchez‐Goñi et al , ; Combourieu‐Nebout et al , ; Incarbona et al , ] and speleothem profiles [ Allen and Huntley , ; McDermott , ; Genty et al , ; Drysdale et al , ; Zanchetta et al , ; Couchoud et al , ; Moreno et al , ] made a strong case of a tight coupling of Mediterranean marine paleoclimatology and terrestrial climate variability over the surrounding borderlands.…”