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  2. Ocean Acidification

An Introduction to Ocean and Coastal Acidification

Bivalve in a seagrass bed
Acidification harms marine life and resources important to humans, like this scallop.

En español

Carbon dioxide is a small percent (about 0.04%) of the gaseous mixture that makes up the atmosphere, but that small amount has a big effect on ocean chemistry. Increasing CO2 uptake by the ocean leads to a suite of changes that are altering the chemistry of the ocean and increasing its acidity. In addition to ocean acidification from carbon dioxide in the atmosphere, land-based sources of pollution can contribute to localized acidification of coastal waters. The causes of ocean and coastal acidification are well understood, but scientists are still documenting its worsening effects. 

Ocean and coastal acidification can harm plants and animals. Shell-forming animals like clams and oysters are particularly vulnerable. Impacts to sensitive species will likely have a ripple effect on all kinds of life in the ocean. Ultimately, key resources like seafood that humans rely on will be affected. Because of this serious issue, EPA is working to address ocean and coastal acidification— and you can help too.

Ocean Acidification

  • Learn about Ocean and Coastal Acidification
  • What EPA is Doing
  • Science and Technology
    • An Introduction to Ocean and Coastal Acidification
    • Understanding the Science
    • Effects on Ecosystems
    • Effects on Marine Life
  • Publications
Contact Us About Ocean and Coastal Acidification
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on April 15, 2025
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