Biogeochemistry of bromine and organic sulfur compounds in the Arctic region

Abstract

Since 1980’s many of atmospheric chemists observed the arctic surface atmosphere, and they concluded that ozone depletion in the arctic air in polar sunrise is caused by catalytic reaction of Br atom originated from the ocean. However, production processes of Br atom are not well known yet. Photolytic reaction at the surfaces of sea-salt and sea-ice is believed to be the main source of Br atom. Photolysis of organic bromine compounds such as bromoform (CHBr₃) produced by macro algae and micro algae should contribute to the Br atom supply. Some studies proposed that CHBr₃ is produced by abiotic reaction at the interface between sea-ice and snow on the sea ice. This review summarizes studies of ozone depleting Br compounds and introduce some recent studies concerning organic bromine compounds.

Also, an organic sulfur gas, dimethyl sulfide (DMS) plays potential roles in atmospheric chemistry and Earth’s climate. DMS is produced from the decomposition of dimethylsulfoniopropionate (DMSP), which is formed within marine algae cells. Recent climate changes, especially in the Arctic Ocean, induce transition of marine biota and its physiology, implying the production/consumption of the marine biogenic compounds will change following the climate change. Here, we also review sulfur cycle in the Arctic Ocean including sea ice zone.