Emissions of CH3Br, organochlorines, and organoiodines from temperate macroalgae

Abstract

The production rates of a range of low molecular weight halogenated organics have been determined in cultures of five temperate species of macroalgae collected from the north coast of Norfolk, England. Compounds studied included CH₃Br, the chlorinated organics CH₃Cl, CH₂Cl₂ and CHCl₃, and the iodinated organics CH₃I, C₂H₅I, and CH₂ClI. Measurements of a wider range of halocarbon concentrations in an isolated rockpool and in air over the seaweed bed were also conducted to evaluate the local impact of the seaweeds on halocarbon concentrations in the natural environment. Estimates for the global emissions of some of the key halogenated compounds from macroalgae have been derived. In general macrophytes appear not to be globally significant producers of the particular halocarbons studied. In coastal regions, however, the impact on local atmospheric composition and chemistry could be greater.