Rapid shoaling of Aragonite Saturation Horizon (ASH) in the Indian Ocean: Influence of accumulation of anthropogenic CO2 and atmospheric pollutants

This data set contains the various cruise data of Aragonite saturation depth in the Northern Indian Ocean. The shallowest aragonite saturation horizon (ASH) was observed in the Bay of Bengal (BoB; 219±10 m) within the tropical Indian Ocean. The ASH shoaled at the rate of 6.3±5 and 4.4±3 m y^-1 in the past two and half decades in the BoB and Arabian Sea respectively. As a result, an increase in total alkalinity (TA) was observed at the rate of 0.5±0.3 and 0.25±0.2 mmol kg^-1 y^-1 at the depth of ASH in the BoB, and Arabian Sea respectively. The rapid shoaling of ASH in the BoB than the Arabian Sea may result from the higher accumulation of anthropogenic CO₂ due to the freshening of the upper ocean associated with an increase in river discharge/ precipitation and deposition of atmospheric pollutants leading to corrosion of the aragonite skeletal material. Under a business-as-usual scenario, aragonite-secreting organisms may not survive by the middle of this century in the BoB.