BROMOFORM EMISSION FROM ARCTIC ICE ALGAE

DESTRUCTION of surface ozone in the Arctic environment during the spring is thought to be caused by photochemical reactions involving bromine compounds1. Berg et al.2 reported a pulse of bromine particles and gases in the Arctic lower atmosphere in spring, which may be responsible for this surface ozone destruction and for which biogenic sources have been hypothesized1-3. Here we report laboratory and in situ measurements which indicate that Arctic ice microalgae emit significant quantities of bromoform (CHBr3), which may be converted photochemically into active forms of bromine. Our estimates of total annual bromoform release indicate that polar ice algae might contribute globally significant amounts of organic bromine compounds, comparable with anthropogenic and macrophyte sources.