Ocean Acidification and its potential impacts on biological resources from the Indian coastal seas

There is overwhelming evidence that ocean warming and acidification (OA) can alter the life cycle of marine organisms, including their physiology, reproduction and growth, ultimately impacting their survival. With an increasing trend in the global atmospheric CO2 levels, it is important to assess how the oceans and coasts are responding with changes in their biogeochemistry and biological resources. CO2 influences the physiology of marine organisms as well through acid-base imbalance and reduced oxygen transport capacity. Under the prevailing rapid warming in the Indian Ocean, OA and its influence on biological resources is of paramount interest. OA is a main component under Sustainable Developmental Goals (SDG-14) that describes life below sea under the changing environment. OA is primarily caused by increasing anthropogenic CO2 emission, however, it is more complicated in the coastal regions as these regions are highly influenced by human-interferences. The ocean receives significant inputs of pollutants, such as deposition of atmospheric pollutants from agricultural fertilizers, and industrial emissions along with natural dust, direct release of partially treated domestic and industrial sewages and input of acidic waters through natural processes, such as upwelling and meridional overturning, submarine groundwater discharge, further enhances OA. Though OA in the coastal waters is aggravated due to human impact, however, quantifying natural versus anthropogenic is highly challenging. OA is usually characterized by declining pH at the rate of 0.0015 to 0.0024/year in the global ocean due to absorption of atmospheric CO2 alone, however, the rate of OA is expected to be more rapid in the coastal waters due to additional sources of both anthropogenic and natural processes mentioned above. India being heavily populated and located in tropics, assessment of OA and its impacts on biogeochemistry and biology of the Indian coastal seas is highly essential. This necessitates the need to devise comprehensive studies and experimental evidence to understand and address the OA effects, with main focus on following aspects:

  • Establish OA changes and identify potential drivers responsible for it.
  • Identify the vulnerable regions for OA along the Indian coast through available and newly generated data.
  • Assess possible impacts of OA on biological resources through in situ mesocosm experiments.