Ocean acidification

The ocean absorbs about a quarter of the carbon dioxide humans release, which slows warming but changes seawater chemistry. When carbon dioxide dissolves in seawater, it forms carbonic acid, which releases hydrogen ions and lowers the water's pH. Average surface ocean pH has fallen by about 0.1, from about 8.2 before the Industrial Revolution to about 8.1 today, which is roughly a 30 percent increase in hydrogen ion concentration, because the pH scale is logarithmic. The ocean is still slightly basic but is becoming more acidic, so the process is called ocean acidification. The extra hydrogen ions combine with carbonate ions, leaving less carbonate for organisms that build shells and skeletons from calcium carbonate, such as corals, oysters, clams, sea urchins, and some plankton. These organisms must spend more energy building shells, and in very corrosive water their shells can dissolve; oyster hatcheries in the Pacific Northwest have lost huge numbers of young oysters when acidic deep water welled up near the coast. Because many food webs depend on plankton and reefs, and warming water also causes coral bleaching, acidification threatens biodiversity and fisheries. Scientists track the change with long-term measurements, such as an ocean station near Hawaii that has recorded seawater carbon dioxide rising along with the atmosphere's, and use models to project future pH under different emission scenarios.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report