1364 / 2024-09-25 17:08:09

Arctic Sea Ice – A Source of Bromine during Polar Night

Arctic sea ice,organo-bromine compounds,MOSAiC,emission

A number of volatile halogenated organic compounds (halocarbons) have been shown to be emitted from the oceans and more lately from sea ice. Several of these contribute to the load of bromine to the troposphere, and are involved in a number of atmospheric processes amongst these the destruction of ozone. It has been shown that first year sea ice (FYI) in the Antarctic contributes significantly to inorganic bromine in the troposphere, and that the produced bromine is spread across the Southern hemisphere. Still, questions have been put forward weather Arctic sea ice is comparable to ice around the Antarctic.

Here we present a suite of measurements of brominated organic compounds in air, surface water and sea ice from autumn to spring collected during the MOSAiC (Multi-disciplinary Drifting Observatory for the Study of the Arctic Climate) expedition from October 2019 to May 2020. Our results show that the surface of first year sea ice is a major source of atmospheric bromine during the dark season, with a ten-fold increase in concentration compared to springtime. Our results shed light over the biogeochemical cycles of organo-bromine compounds and the processes governing the emissions.