The purpose of this study is to examine possible natural marine sources and removal mechanisms which contribute to the oceanographic distribution of volatile halogenated compounds, particularly the low molecular weight organobromines. Ocean to atmosphere fluxes of organic bromine ultimately provide atmospheric bromine radical species which themselves, or synergistically with chlorinated analogues, can catalytically destroy ozone. Altered ozone concentrations could potentially affect atmospheric stability and the thermal energy balance of the planet as well as the biologically crucial ultraviolet-shielding capability of the ozone layer.
Indications are that ozone variability is greatest in the polar regions.
Halogenated compounds also have anthropogenic sources, but germane to any understanding of the relative impact of anthropogenic perturbations of ozone is the elucidation of the natural cycles of the substances of concern. Measurements of low molecular weight organobromines at various locations in the ocean have indicated higher concentrations of these dissolved gases in coastal regions than in offshore waters, a distribution usually attributed to the known production of such compounds by macroalgae, which are generally confined to shallower waters. However, such a spatial allocation could also be consistent with a sediment source. A principal objective of this thesis was to establish whether or not Arctic marine sediments could be a source of volatile brominated organics. Motivation for a study in the Arctic was furnished by reports that atmospheric bromine is more significantly involved in the variability of both tropospheric and stratospheric ozone at high northern latitudes than in the Antarctic scenario.