Collaborative Research: BEACON: The Bellingshausen Sea, A Carbon and Overturning Nexus

Global sea levels are rising at unprecedented rates and will continue to reshape the coastline of densely populated regions both in the US and globally with implications for housing, transportation, agriculture, wildlife habitability, and tourism. Over the next 50 years, mass loss from the Antarctic Ice Sheet will be a dominant contribution to global sea level, but it is also associated with the greatest uncertainty in sea level rise estimates. Much of this uncertainty results from incomplete understanding of processes that occur near the Antarctic coast where there are close interactions between the open ocean, near-coastal waters whose properties are influenced by interactions with sea-ice, and ocean water that is carrying glacier meltwater originating from the Antarctic ice sheet itself. These regions also happen to be among the most biologically productive of all waters in the Southern Ocean, and the impact of climate-related biogeochemical changes here remain a blind spot in our understanding of a changing global carbon cycle. Current understanding of changes occurring around Antarctica are largely derived from decades of work in the Amundsen Sea. Yet, the melting of ice shelves in the neighboring Bellingshausen Sea are comparably high and pre-condition the physical and biogeochemical properties of the water that enter the Amundsen. Thus, the role of the “upstream” Bellingshausen Sea in ice sheet mass loss and ocean carbon uptake remains unconstrained, although models suggest this region can broadly influence these processes throughout West Antarctica. The Bellingshausen Sea: A Carbon and Overturning Nexus (BEACON) project will collect a broad suite of physical and biogeochemical observations needed to assess the Bellingshausen Sea’s role in the large-scale distributions of heat, meltwater, dissolved iron and other nutrients, and biological productivity. The research team will combine standard and trace-metal shipboard measurements, towed underway observations, and a small fleet of remote autonomous underwater vehicles aimed at capturing key transport pathways associated with narrow boundary currents located along the coast. These observations will capture dynamical processes related to mixing of water properties by ocean turbulence from centimeter to kilometer scales. This information about mixing will then be applied to an inverse-modeling framework to assess how changes in near-coastal processes in the Bellingshausen Sea impact larger-scale ice-shelf melt rates, nutrient supply to the upper ocean, the timing and intensity of seasonal primary production, and the oceanic uptake of carbon dioxide throughout West Antarctica. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.