Summary of Abstract Submission

Abstract Submission No. IO50-03-0013PresentationOral

RAPID ACIDIFICATION IN THE NORTHERN BAY OF BENGAL DUE TO AEROSOL DEPOSITION

V.V.S.S. Sarma*1

1 National Institute of Oceanography, India

ABSTRACT :

Ocean acidification is decrease in pH of ocean caused by the uptake of carbon dioxide (CO2) from the atmosphere. This is further enhanced by anthropogenic inputs, such as acidic aerosols, acidic effluents. The Bay of Bengal is covered by land mass from the South and Southeast Asia where rapid increase in anthropogenic activities were noticed. In order to examine impact of aerosol deposition on ocean acidification, time-series observations and models studies were conducted for past two decades. The observations conducted during spring 1991 and 2011 suggested that significant decrease in pH and increase in pCO2 levels (by 3 to 5 times) in the northern compared to elsewhere in the world. The seasonal trends of pCO2 derived from multi linear regression model suggested that the rate of increase in pCO2 is higher during January to May (3-5 atm/month) compared to other seasons (1-2 atm/y) in the northern Bay between 1997 and 2014. The annual growth rate of pCO2 was also higher in the northern Bay (2.8 atm/y) than other ocean basins (1.2 atm/y). The increase in pCO2 levels were in agreement with recent increase in sulfate and nitrogen aerosol loadings over northern Bay of Bengal from the Indo-Gangetic Plain and Southeast Asia during winter and spring and also increased industrialization and fertilizer consumption over Indian subcontinent. As a result, the Bay of Bengal, which was previously considered as a significant sink for atmospheric CO2, now seems to have turned into a region of CO2 source to atmosphere.