Extreme Indian Monsoon Regimes Lead to Collapses in Oceanic Productivity
Speaker: Kaustubh Thirumalai, Assistant Professor, College of Geosciences, University of Arizona
Kaustubh Thirumalai’s presentation will be held in Room AB20 in Weeks Hall and will also be available to watch via Zoom. Register to watch via Zoom.
Indian summer monsoon (ISM) hydrology fuels biogeochemical cycling across South Asia and the Indian Ocean, exerting a first-order control on food security in Earth’s most densely-populated areas. Despite projected ISM intensification under greenhouse forcing, large uncertainty surrounds future Indian Ocean stratification and primary production — processes key to the health of already vulnerable fisheries in the region.
In his talk, Dr. Thirumalai will present centennially resolved records of ISM runoff and marine biogeochemical fluctuations in the Bay of Bengal (BoB) since the Last Glacial Maximum (LGM; about 21,000 years ago). Counterintuitively, records indicate that BoB productivity collapsed during both extreme states of peak monsoon intensity (EH) and failure (HS1). In contrast to the latest Earth-system model projections, Dr. Thirumalar et al.’s paleoceanographic results raise the possibility of future deterioration in BoB productivity under strengthening monsoon seasonality.