Ocean Acidification

Ocean acidification is the ongoing decrease in ocean pH caused by absorption of carbon dioxide (CO₂) from the atmosphere. When seawater absorbs CO₂, it forms carbonic acid, making the ocean measurably more acidic—about 30% more acidic since the Industrial Revolution.

This process threatens marine life at every scale. Shellfish, Sea Turtles, and countless other organisms rely on calcium carbonate to build shells and skeletons; acidic water dissolves these structures. Coral reefs—already stressed by warming waters—face accelerated bleaching and slower growth. Even microscopic plankton, foundational to Ocean ecosystems, struggle to calcify in acidified conditions, disrupting the entire food web.

The mechanism is straightforward: as atmospheric CO₂ rises (driven by human activity), more dissolves into seawater. This alters the carbonate chemistry that marine organisms evolved with over millions of years. The rate of change is unprecedented in geological history, leaving many species with insufficient time to adapt.

Scientists track acidification through monitoring of pH levels and carbonate ion concentrations across major ocean regions. The impacts compound with other Climate change stressors, creating cascading ecological consequences that ripple through food chains and human fisheries alike.

Related

Carbon dioxide, Marine biology, Coral reefs, Biogeochemistry, Environmental science