Antarctic Sea Ice and Snow Microbial Bromocarbon Processes

  PI: Karen Junge

Naturally produced brominated organic compounds are ubiquitous in the oceans and are thought to be largely responsible for the formation of the Antarctic “ozone hole” in Spring. In order to accurately model and forecast global ozone and the climate, it is critical to include reactive bromine and brominated organic compounds (bromocarbons). However, bromocarbon measurements for the Antarctic are limited, especially during Spring. Recently, Antarctic winter sea ice and in particular the brine-wetted saline layers of the overlying snow were measured and have been calculated to unexpectedly contribute ~40% of the global tropospheric reactive bromine budget (Abrahamsson et al., 2018). Since microorganisms, including polar marine algae and bacteria, are identified as the main natural producers and degraders of bromocarbons and are known to be metabolically active in Antarctic snow and sea ice (Carpenter et al. 2000, Junge et al., 2019), it is critical to quantify their contribution to these processes, especially in atmospheric-interface snow overlying sea ice. To date, the vast (~18×10^6km^2) Antarctic sea-ice snow environments and their microbial communities have not been examined with this perspective in mind. In this pilot study, funded by the Office of Polar Programs at the National Science foundation, we will use advances in microbiological, metagenomic, metaproteomic and bromocarbon measurement techniques to test for and quantify the microbial participation in the production and degradation of atmospheric bromocarbons in Antarctic sea-ice snow in the Ross Sea near McMurdo Research station during early Spring, an understudied, yet extensive, surface environment. We hope that our work will contribute towards the improvement of projections of Antarctic ozone hole recovery in the XXI century and predictions of bromocarbon contribution to global ozone and climate processes. 

Our team deployed in early October 2023 for a two-month field season near McMurdo, Antarctica, Webcams. Stay tuned here for our blog and video updates by Emma from the field!

                                                                                                  You can check out a few project slides and team members with pictures here.

                                                                                                  Check back for weekly updates from the field!