Environ. Sci. Technol. 1997, 31, 3188-3192
Marine Bacterial Degradation of Brominated Methanes
RONALD S. OREMLAND
This study investigated the existence, character, and extent of marine microbial degradation of CH2Br2 and CHBr3 in order to better understand the biogeochemistry of these compounds and to determine whether microbial degradation could alter estimates of brominated methane production or emission by algae. To this end, we studied microbial degradation of CH2Br2 and CHBr3 in sites of significant brominated methane production, namely Macrocystis pyrifera kelp beds. We describe for the first time degradation of CH2Br2 by bacteria from a marine system and show that CH2Br2 is oxidized to CO2 by these microbes.
National Research Program, United States Geological Survey, 345 Middlefield Road MS 480, Menlo Park, California 94025
Materials and Methods
KELLY D. GOODWIN* AND MARY E. LIDSTROM† Environmental Engineering Science 138-78, California Institute of Technology, Pasadena, California 91125
Brominated methanes are ozone-depleting compounds whose natural sources include marine algae such as kelp. Brominated methane degradation by bacteria was investigated to address whether bacterial processes might effect net emission of these compounds to the atmosphere. Bacteria in seawater collected from California kelp beds degraded CH2Br2 but not CHBr3. Specific inhibitors showed that methanotrophs and nitrifiers did not significantly contribute to CH2Br2 removal. A seawater enrichment culture oxidized 14CH Br to 14CO as well as 14CH Br to 14CO . The rates of 2 2 2 3 2 CH2Br2 degradation in laboratory experiments suggest that bacterial degradation of CH2Br2 in a kelp bed accounts for
