Ocean Acidification

Ocean acidification refers to the decrease in the pH of the ocean that has occurred during the 20th and 21st centuries due to the absorption of excess carbon dioxide from the atmosphere, which has been put there by human activity, such as the excessive use of fossil fuels. The process has altered the chemistry of seawater, reducing the availability of carbonate ions needed by marine organisms, such as corals and shellfish, to build their shells and skeletons. Ocean acidification therefore threatens marine ecosystems and biodiversity.