Late Pleistocene variations of the diatom productivity in the high-latitude Atlantic: convergence shifts, nutrient availability, and rapid climate variability

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This project will address the variability of the siliceous paleoproductivity in the Subarctic Atlantic (Site U1304) and its relation to climatic, biogeochemical and hydrographic events occurred during the last 450 kyr. Site U1304 (ca. 53ºN, 33ºW) represents a high-sedimentation record of late Pliocene and Pleistocene environmental conditions in the high-latitude Atlantic. By exploring the long-term and the rapid variations (<103 yr) in the diatom community occurred during the late Pleistocene, we will address the variations of diatom production related with North Atlantic climate history and the shift between production of siliceous and calcareous organisms. Opal, and major and trace elements will help to characterize variations of productivity and latitudinal migration of the Subarctic Convergence. The study of long sequences of diatom-rich laminated sediments at Site U1304 will deliver ultra-high resolution information on climate and hydrography variability of the subpolar Atlantic. The proposed multi-parameter approach will contribute to the comprehension of the relative phasing of atmospheric and oceanic changes in the high-latitude North Atlantic that are central to our understanding of the mechanisms of global climate change on orbital to millennial timescales.