Atmospheric Input and Ocean biogeochemistry
Oceans have shaped us to become what we are today and have an impact on our future, hosting 90 percent of the life of the Planet, natural resources, biodiversity, weather and climate interaction and, most importantly, becoming the base of life. Ocean primary productivity, with the major contribution of phytoplankton, is the elementary stage of the oceanic food chain. The chlorophyll pigment in the phytoplankton can be identified by the sensors onboard satellites so that the amount of phytoplankton can be determined.
Our team in association with India Meteorological Department (IMD) and National Institute of Ocean Technology (NIOT) studies the spatial and temporal changes in the phytoplankton and its response to climate change. Also, we look into the winter blooms in the Arabian Sea, the monsoon blooms around Sri Lanka and the importance of eddies in transporting heat, trace chemicals and nutrients. The ocean's productivity depends on the prevailing oceanic conditions and, moreover, on the atmospheric supply. Atmospheric inputs, especially aerosols, have different effects on oceanic productivity. It is found that the trace metals in mineral dust have a positive effect on production, while in certain oceanic areas, iron in dust acts as a limiting factor.
We investigate the various natural and anthropogenic sources of these minerals and aerosols, and we evaluate how they can alter natural carbon, nitrogen and other cycles in the ocean and their interconnections. For this, we rely on satellite observations, measurements of buoys and cruises, as well as numerical models. In collaboration with Indian National Centre for Ocean Information Services (INCOIS) and Indian Institute of Tropical Meteorology (IITM), the modeling of Indian Ocean biogeochemistry paired with atmospheric chemistry is crucial in understanding the internal mechanisms and processes that regulate various effects of atmospheric aerosols and pollution on marine biogeochemistry. Our study unveils the response of ocean biogeochemistry to climate change which is essential in implementing countermeasures to curb adverse effects.