The oceans currently absorb approximately one-third of total emissions of carbon dioxide (CO2) generated by fossil-fuel combustion. As CO2 is absorbed by the ocean, it forms carbonic acid and lowers the slightly alkaline (basic) pH of seawater. This suite of chemical changes is known collectively as ocean acidification. Lowered ocean pH alters the ability of many calcifying marine organisms to produce calcium carbonate skeletons and shells. Ocean acidification is an emerging global problem because, as CO2 emissions continue, so will the lowering of ocean pH that may cause profound changes in marine food webs and global ecosystems. (See related Sound Waves articles “Impacts of Ocean Acidification on Coral Growth: Historical Perspectives from Core-Based Studies,” “Research Cruises Collect Measurements on the West Florida Shelf for Modeling Climate Change and Ocean Acidification,” and “Coral-Reef Builders Vulnerable to Ocean Acidification.”)
The U.S. Geological Survey (USGS), along with other federal agencies, is working with the international scientific community to help standardize and compile information that adequately describes ocean chemistry trends and analyzes relations between these trends and carbon sources, cycles, and human activities. The USGS has been pioneering work to improve capabilities in measuring marine carbonate species and metabolic cycles that affect carbon compounds (http://coastal.er.usgs.gov/flash/), as well as characterizing CO2 concentrations in a wide variety of marine environments (http://coastal.er.usgs.gov/crest/).
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Ann B. Tihansky, USGS science for a changing world, August/September 2010. Full article.
