WASHINGTON -- The changing chemistry of the world's oceans is a growing global problem, says the summary of a congressionally requested study by the National Research Council, which adds that unless man-made carbon dioxide (CO2) emissions are substantially curbed, or atmospheric CO2 is controlled by some other means, the ocean will continue to become more acidic. The long-term consequences of ocean acidification on marine life are unknown, but many ecosystem changes are expected to result. The federal government's National Ocean Acidification Program, currently in development, is a positive move toward coordinating efforts to understand and respond to the problem, said the study committee.
The ocean absorbs approximately a third of man-made CO2 emissions, including those from fossil-fuel use, cement production, and deforestation, the summary says. The CO2 taken up by the ocean decreases the pH of the water and leads to a combination of chemical changes collectively known as ocean acidification.
Since the beginning of the industrial revolution, the average pH of ocean surface waters has decreased approximately 0.1 unit -- from about 8.2 to 8.1 -- making them more acidic. Models project an additional 0.2 to 0.3 drop by the end of the century. This rate of change exceeds any known to have occurred in hundreds of thousands of years, the report says. The ocean will become more acidic on average as surface waters continue to absorb atmospheric CO2, the committee said.
Studies on a number of marine organisms have shown that lowering seawater pH with CO2 affects biological processes, such as photosynthesis, nutrient acquisition, growth, reproduction, and individual survival depending upon the amount of acidification and the species tested, the committee found. For example, some of the strongest evidence of the potential effects of ocean acidification on marine ecosystems comes from experiments on organisms with calcium carbonate shells and skeletons. The results showed decreases in shell and skeletal growth in a range of marine organisms, including reef-building corals, commercially important mollusks such as oysters and mussels, and several types of plankton at the base of marine food webs.
The ability of various marine organisms to acclimate or adapt to ocean acidification is unknown, but existing data suggest that there will be ecological winners and losers, leading to shifts in the composition and functioning of many marine ecosystems, the committee said. Such ecosystem changes could threaten coral reefs, fisheries, protected species, and other natural resources.
Although changes in ocean chemistry caused by increasing atmospheric CO2 can be determined, not enough information exists to assess the social or economic effects of ocean acidification, much less develop plans to mitigate or adapt to them, the committee noted.
The federal government has taken initial steps to respond to the nation's long-term needs with the development of the National Ocean Acidification Program. The committee found that legislation has laid the foundation for a program that will advance our understanding and improve our response to ocean acidification.
The committee recommended six key elements of a successful National Ocean Acidification Program:
The study is funded by the National Oceanic and Atmospheric Administration, NASA, the U.S. Geological Survey, and the National Science Foundation. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies. They are independent, nonprofit institutions that provide science, technology, and health policy advice under an 1863 congressional charter. Committee members, who serve pro bono as volunteers, are chosen by the Academies for each study based on their expertise and experience and must satisfy the Academies' conflict-of-interest standards. The resulting consensus reports undergo external peer review before completion. For more information, visit http://national-academies.org/studycommitteprocess.pdf. A committee roster follows.
Copies of the summary for the report OCEAN ACIDIFICATION: A NATIONAL STRATEGY TO MEET THE CHALLENGES OF A CHANGING OCEAN are available from the National Academies Press; tel. 202-334-3313 or 1-800-624-6242 or on the Internet at HTTP://WWW.NAP.EDU. Reporters may obtain a copy from the Office of News and Public Information (contacts listed above).
[ This news release and summary of the study are available at HTTP://NATIONAL-ACADEMIES.ORG ]
NATIONAL RESEARCH COUNCIL
Division on Earth and Life Studies
Ocean Studies Board
COMMITTEE ON DEVELOPMENT OF AN INTEGRATED SCIENCE STRATEGY FOR OCEAN ACIDIFICATION MONITORING, RESEARCH, AND IMPACTS ASSESSMENT
FRANCOIS M.M. MOREL * (CHAIR)
Albert G. Blanke Jr. Professor of Geosciences
Director, Center for Environment BioInorganic Chemistry
Department of Geophysical Sciences
University of Chicago
JAMES P. BARRY
Monterey Bay Aquarium Research Institute
Moss Landing, Calif.
GARRY D. BREWER
Frederick K. Weyerhauser Professor of Resource and Policy Management
School of Mangement
New Haven, Conn.
JORGE E. CORREDOR
Department of Marine Sciences
University of Puerto Rico - Mayaguez
SCOTT C. DONEY
Department of Marine Chemistry and Geochemistry
Woods Hole Oceanographic Institution
Woods Hole, Mass.
VICTORIA J. FABRY
Professor of Biology
Department of Biological Sciences
California State University
GRETCHEN E. HOFMANN
Department of Ecology, Evolution, and Marine Biology
University of California, Santa Barbara
DANIEL S. HOLLAND
Gulf of Maine Research Institute
JOAN A. KLEYPAS
National Center for Atmospheric Research
FRANK J. MILLERO
Professor of Marine and Physical Chemistry
Rosentiel School of Marine and Atmospheric Science
University of Miami
Head of Biological Oceanography
Marine Biogeochemistry/Biological Oceanography
Leibniz Institute of Marine Sciences
RESEARCH COUNCIL STAFF
* Member, National Academy of Sciences
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