This project is a study of organic bromine chemistry in the lower arctic atmosphere, particularly in relation to tropospheric destruction of ozone. It has been observed that shortly after the arctic sunrise, surface ozone concentrations decline from a late winter maximum to near zero before recovering to moderately high summer values. There is also strong evidence which implies that the primary cause for the minimum is the photolytic production of bromine radicals from organic bromine gases, which then combine with ozone. The chemical pathways are conjectural and little is known about the origins of the organic bromine, but it is believed that a marine source is the most probable. This study addresses the latter question through a sampling and analysis program at Resolute, N.W.T., Canada, focusing on macrophytes, phytoplankton, ice algae, benthic microalgae, and bacteria. These will be tested for organohalogen content and production/emission of bromine, chlorine, and iodine species, as well as oxygen and carbon-14. Physiological studies will describe environmental factors influencing release rates and coupling with other metabolic processes. Atmospheric observations, including particulate bromine, and organic and inorganic gaseous bromine, are the subject of a separate project. Supporting ozone and meteorological variables are measured routinely at the Barrow Observatory of the Geophysical Monitoring for Climatic Change Program of the National Oceanic and Atmospheric Administration.
