Definition

The reduction in ocean pH (meaning the ocean is more acidic) due to atmospheric carbon dioxide dissolving into seawater. This reduces availability of carbonate ions which negatively affects calcifying organisms like shellfish and coral. This has wider negative impacts on marine ecosystems.

Further reading
What is Ocean Acidification? - National Oceanic and Atmospheric Administration (NOAA) [website]
Related

calcium carbonate (CaCO3); carbon cycle; carbonic acid (H2CO3); decreasing pH; estuarine acidification; fishing; hydrogen ions; increasing acidity; marine biogenic calcification; marine degradation; marine pollution; ocean degradation; ocean deoxygenation; oceanic carbon cycle; seawater pH

See also
Coral bleaching
Food security
Greenhouse Gases (GHGs)
Oceanic sink
Planetary boundaries
Explore by theme
Challenges
Environmental Changes
Drafted by
Chris Graham
Reviewed by
TBC