• NH3;
  • NOx;
  • Sox;
  • carbon dioxide;
  • ocean acidification

[1] The acidification of the ocean by anthropogenic CO2 absorbed from the atmosphere is now well-recognized and is considered to have lowered surface ocean pH by 0.1 since the mid-18th century. Future acidification may lead to undersaturation of CaCO3 making growth of calcifying organisms difficult. However, other anthropogenic gases also have the potential to alter ocean pH and CO2 chemistry, specifically SOx and NOx and NH3. We demonstrate using a simple chemical model that in coastal water regions with high atmospheric inputs of these gases, their pH reduction is almost completely canceled out by buffering reactions involving seawater HCO3 and CO32− ions. However, a consequence of this buffering is a significant decrease in the uptake of anthropogenic CO2 by the atmosphere in these areas.