Discerning Boron to Salinity Ratios in Arctic Marginal Ice Zones - BAMZ

The Arctic Ocean has an important role in regulating earth’s climate. Though it is only 3% of the total ocean it takes up 10% of the carbon dioxide we add to the atmosphere every year. Though the Arctic has always had a permanent ice cap, it is shrinking in size and by the year 2040 the permanent summer ice cap will be gone.

This implies that there will be an increased intensity in the amount of ice that melts each year and there is little known about how the melting ice will alter Arctic surface water chemistry. This study will sample Arctic Sea ice, snow, and brine to map its chemistry profiles in the eastern Arctic with the goal of making better predictions in the future Arctic environment as the Arctic climate changes.

The main focus is on the ice profiles of boron and salinity which have a constant ratio in the open ocean, but this ratio may shift in the marginal ice zone at salinities that are less than 30 g/kg and are freshened by melt. This project will also create lessons that show how we use chemistry to do this work and understand climate.

This project joins the Atmospheric rivers and the onset of sea ice melt (ARTofMELT) Expedition on the I/B Oden in May June 2023 to conduct sampling in the marginal ice zone (MIZ), including ice cores and brine. The goal is to discern the boron to salinity ratios of these unique systems and their impact on total alkalinity and uptake of atmospheric CO2.

The objectives include; 1) to determine the boron to salinity (B/S) ratios in Arctic sea-ice and brine, 2) to determine the carbonate system parameters in Arctic sea-ice and brine, 3) to compare the profiles of all above parameters in annual vs multi-year ice and brine, 4) to evaluate changes in these parameters over the ice-melt process at a given ice station, and 5) to assess the impact on B/S ratios and total alkalinity in adjacent meltwaters of the MIZ. Intellectual Merit: This study contributes to biogeochemical, physical oceanographic, meteorological and climate change research.

The results of the B/S ratios will provide important corrections to total alkalinity analyses in polar regions and improve parameterizations in future Arctic CO2 uptake estimates and modeling efforts. Most notably, this study will provide the first ever boron to salinity profiles in annual ice in this region and the first multiyear ice profiles in any region.

In addition, ice and brine profiles of other biogeochemically relevant parameters will be generated. It is expected that the results of this study will provide new insights on the future biogeochemistry of the warming Arctic and Arctic CO2 uptake. Broader Impacts: Ten paired videos (from the cruise) and lesson plans will be generated that target high school and undergraduate chemistry students based on chemical concepts used in this research (equilibrium constants, acidity constants, etc.).

Following the cruise these will be posted on the project webpage and shared with PBS Learning Media and other educational resource platforms. All lessons will introduce the theme of Arctic ice loss. Researchers will also continue to work with senior illustration students to create Arctic sea ice retreat themed projects (books, posters, short animations) for the broader public.

This project will create opportunities for two female graduate students, one of which will have the opportunity for international collaboration in Boron analysis in Korea, and at least four undergraduate students from minority groups through an REU program and the FirstGen program at University of Connecticut.

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.