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Title: The Inhibition of Marine Nitrification by Ocean Disposal of Carbon Dioxide

Journal Article · · Marine Pollution Bulletin

In an attempt to reduce the threat of global warming, it has been proposed that the rise of atmospheric carbon dioxide concentrations be reduced by the ocean disposal of CO2 from the flue gases of fossil fuel fired power plants. The release of large amounts of CO2 into mid or deep ocean waters will result in large plumes of acidified seawater with pH values ranging from 6 to 8. In an effort to determine whether these CO2-induced pH changes have any effect on marine nitrification processes, surficial (euphotic zone) and deep (aphotic zone) seawater samples were sparged with CO2 for varying time durations to achieve a specified pH reduction and the rate of microbial ammonia oxidation was measured spectrophotometrically as a function of pH. For both seawater samples taken from either the euphotic or aphotic zone, the nitrification rates dropped drastically with decreasing pH. Relative to nitrification rates in the original seawater at pH 8, nitrification rates are reduced by ca. 50% at pH 7 and more than 90% at pH 6.5. Nitrification is essentially completely inhibited at pH 6.

Research Organization:
Pacific Northwest National Lab., Richland, WA (US)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
AC06-76RL01830
OSTI ID:
15001278
Report Number(s):
PNNL-SA-33944; TRN: US200401%%595
Journal Information:
Marine Pollution Bulletin, Vol. 44, Issue 2; Other Information: PBD: 1 Feb 2002
Country of Publication:
United States
Language:
English