This “Building Resilience” feature is contributed by the Reef Resilience program of The Nature Conservancy ( The program provides reef managers with tools to build resilience into management activities.

By Rebecca Cerroni and Stephanie Wear, The Nature Conservancy

The chemistry of the ocean is dependent on the chemistry of the atmosphere. As the amount of atmospheric CO2 increases due to the burning of fossil fuels, the amount of CO2 that dissolves in the ocean also increases. Since CO2 and water combine to form carbonic acid, “ocean acidification” (meaning a lower pH level for the sea) occurs when more than the usual amount of CO2 is dissolved.

Water that is more acidic has fewer available carbonate ions, an essential ingredient in the calcification process used by corals, shellfish, and other creatures. As the supply of carbonate declines, these organisms’ ability to build reefs and shells is weakened. The survival of larval marine species, including commercially valuable fish, may also be reduced.

Here are management tips to prepare for ocean acidification:

  • Prioritize protection of habitats that are likely to be resistant to acidification. These include reefs in naturally carbonate-rich areas (such as sites with carbonate-rich sediments), well-flushed reefs, and seagrass meadows. Due to their photosynthesis, seagrasses actually benefit from increases in CO2and can serve to absorb CO2 from neighboring habitats.
  • Review management plans to incorporate the latest research on acidification, since knowledge of its ecosystem impacts is evolving quickly. A list of recent science is at
  • Integrate ocean management with land use planning and coastal zone planning to help reduce pollutants that can also increase the acidity of local waters. These pollutants include ammonium compounds, nitrogen oxides, and sulfur oxides.

For more information on ocean acidification, go to