Degradation of Methyl Bromide and Methyl Chloride in the Oceans

University Of California-Irvine, Irvine CA

Investigators

Abstract

ABSTRACT OCE-0221472 The importance of tropospheric halocarbons as a source for stratospheric halogens and ozone depletion is well recognized. Industrial production of longer-lived CFC's have been banned under the Montreal Protocol and Clean Air Act, however the time scale for recovery of the ozone layer from such molecules is on the order of decades. As a result, attention has shifted towards the shorter-lived halocarbons that respond more rapidly to changes in emissions. In this project, researchers at the University of California at Irvine will continue their ongoing efforts to understand the role of the oceans in the biogeochemical cycling of low molecular-weight halocarbons, like methyl bromide (CH3Br) and methyl chloride (CH3Cl). In this phase of their research, oceanic degradation studies will be continued in order to extend prior spatial and temporal coverage of the oceans, and to include methyl chloride (CH3Cl). The degradation of other natural halogenated compounds such as dibromomethane (CH2Br2), bromoform (CHBr3), and methyl iodide (CH3I) will also be studied in coastal seawater. The proposed measurements will result in revised estimates for the uptake of atmospheric halocarbons by the oceans, the extent to which the oceans can buffer atmospheric halocarbon concentrations, and the production rate for these gases in the surface oceans.