Modeling pCO{sub 2} in the upper ocean: A review of relevant physical, chemical, and biological processes

Technical Report · Sat Dec 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/538037· OSTI ID:538037

The pCO{sub 2} of the surface ocean is controlled by a combination of physical, chemical, and biological processes. Modeling surface ocean pCO{sub 2} is analogous to modeling sea surface temperature (SST), in that sea surface pCO{sub 2} is affected by fluxes across the air-sea interface and by exchange with deeper water. However, pCO{sub 2} is also affected by chemical and biological processes which have no analog in SST. Seawater pCO{sub 2} is buffered by pH equilibrium reactions between the species CO{sub 2}, HCO{sub 3}-, and CO{sub 3}{sup =}. This effect provides an effective reservoir for CO{sub 2} in seawater that is 10 times larger than it would be for an unbuffered gas. The equilibrium between dissolved and atmospheric CO{sub 2} is sensitive to temperature, tending to higher pCO{sub 2} in warmer water. Biological export of carbon as sinking particles maintains a gradient of pCO{sub 2}, with lower values near the surface (this processes is called the {open_quotes}biological pump{close_quotes}). In most of the ocean, biological activity removes all of the available nutrients from the surface water; that is, the rate of carbon export in these locations is limited by the rate of nutrient supply to the euphotic zone. However, in much of the high-latitude oceans, primary production does not deplete the euphotic zone of nutrients, a fact to which the atmospheric pCO{sub 2} is extraordinarily sensitive. Understanding the limits to phytoplankton growth in the high latitudes, and how these limits might change under different climatic regimes, is essential to prediction of future ocean uptake of fossil fuel CO{sub 2}.

• Research Organization: Battelle Memorial Inst., Columbus, OH (United States). Office of Nuclear Waste Isolation
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 538037
• Report Number(s): DOE/RL/01830--T-H5; TRO--50; ON: DE98000432
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
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CARBON CYCLE
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ENVIRONMENTAL EFFECTS
FORECASTING
GEOCHEMISTRY
GREENHOUSE EFFECT
GREENHOUSE GASES
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USA