Late PLiocene dIAtom productivity in the western Bay of Bengal: Response to Indian MOnsoon evolution and teleconnections

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The Indian Monsoon (iMonsoon, a subsystem of the Asian Monsoon) is one of the most powerful meteorological phenomena on Earth, affecting the lives of over a billion people. However, its behavior in the near future under the influence of anthropogenic climate change is uncertain, particularly in terms of the intensity and distribution of seasonal precipitation. The Pliocene is the most recent period in Earth history with similar elevated global temperatures and CO2 levels to those predicted for the coming century, and may serve as a useful analogue for future climate and monsoon behavior. This project will utilize sediments from Site U1445 (western Bay of Bengal) recovered during 353X. As this region has never been scientifically drilled before 353X, high-resolution core U1445 represents an unparalleled opportunity to better constrained the past behavior of the iMonsoon during the last Pliocene and its effect on surface water productivity through the application of sophisticated multi-proxy techniques. Here diatoms, biogenic silica, total organic carbon and diatom-based d30Si data will be generated to reconstruct siliceous paleoproductivity and Si content changes of surface waters at high resolution (ca. 3-3.4 kyr) allowing us to track the changing response of the siliceous productivity to summer iMonsoon before during and after the Northern Hemisphere Glaciation (ca. 3.5-2.5 Ma). Additionally, the occurrence of land-derived plant remains (freshwater diatoms and phytoliths) will help to elucidate the issue of riverine input of nutrients due to summer iMonsoon-induced precipitation discharge vs water masses-transported nutrients. These records will be compared to proxies for paleohydrology and vegetation cover (pollen, charcoal, XRF-gained elements), and foraminifer assemblage data from the same samples, which will allow a holistic picture of orbitally-paced climatic change to be constructed. New material from this critical region will allow us to assess the relative sensitivity of the monsoon to external insolation forcing and internal climate boundary conditions, including the extent of global ice volume, the export of nutrients from the Southern Hemisphere, and greenhouse gas concentrations. The proposed research is a collaborative effort involving several 353X ship-based researchers from Germany, United Kingdom and USA.