Science
Ocean acidification.
Definition
Ocean acidification is the ongoing decrease in ocean pH caused by the absorption of excess atmospheric CO₂. When CO₂ dissolves in seawater, it forms carbonic acid, which releases hydrogen ions and lowers pH. This threatens marine organisms that build calcium carbonate shells and skeletons.
Examples
Real-world.
- 1 Coral reefs weakening as lower pH reduces their ability to build calcium carbonate skeletons
- 2 Oyster larvae failing to form shells in acidified waters along the U.S. Pacific coast
- 3 Pteropods (sea butterflies) showing dissolving shells in acidic Southern Ocean waters
Key Fact
Ocean pH has dropped from ~8.2 to ~8.1 since the Industrial Revolution — a 26% increase in acidity.