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Effects of Increasing Atmospheric CO2 on Coral Reefs

This ISSE project focuses on how coral reefs and other marine ecosystems are affected by environmental changes associated with global climate change, such as increases in in sea surface temperature and ocean acidification.

For some time, researchers have been making dire predictions for the world's reefs if the impact of humans is not curtailed. Joan Kleypas examined how two consequences of increased atmospheric CO2 concentration, greenhouse warming and changes in seawater chemistry, are affecting both coral reef organisms and the reef structures that they build. A major threat to coral reefs is the significant increase in summertime maximum temperatures, which induces a “coral bleaching” stress response that can lead to large-scale mortality of reef organisms. Kleypas and colleagues are combining CCSM (Community Climate System Model) output to help predict the probability of coral bleaching in future greenhouse scenarios.

A second threat to reefs is the increase in ocean acidity, which hampers calcium carbonate production. Kleypas and colleagues at NOAA and Columbia University have designed a field program to document seawater chemistry changes on a reef at the Caribbean Marine Research Center (CMRC) in the Bahamas. Through funding from the NCAR Opportunity Fund, the group deployed an automated seawater sampling system onto an existing time-series station on a reef near the CMRC to enable documentation of the diurnal cycle in seawater carbonate chemistry on the reef. This information will be used along with other time-series data (e.g., temperature, salinity, light, wind) to model coral reef calcification and organic production in response to environmental variables.

Additionally, Kleypas co-authored a study published in FY04 by the Pew Center on Global Climate Change entitled Coral Reefs and Global Climate Change: Potential Contributions of Climate Change to Stresses on Coral Reef Ecosystems.


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The Institute for the Study of Society and Environment is part of the National Center for Atmospheric Research, which is managed by the University Corporation for Atmospheric Research and is sponsored by the National Science Foundation.
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