Award: OPP-1753418

The research project proposal requested funds to participate in the international Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) during 2019-2020. The project goal was to observe the transfer of material from the atmosphere to sea ice and the open ocean through atmospheric deposition. Samples of aerosols and precipitation were collected from December 2019 to May 2020. In total, 26 collections were completed. These samples include bulk aerosols as well as aerosol samples divided by particle size. This material has been processed in the laboratory and analyzed to describe the chemical composition. Overall, aerosol concentrations in the Arctic were low with elements of interest present at levels of nanograms per cubic meter of filtered air. Lithogenic elements like iron, aluminum, titanium, and thorium remained consistently low in the samples from the central Arctic. These elements did not increase in concentration until the ship began to travel toward the North Atlantic in May 2020. In contrast, elements produced by anthropogenic activities including copper, zinc, nickel, and chromium were relatively higher during the winter months (December-March) than during the spring (April-May). This latter group of elements was also enriched in the collected samples compared to typical values in crustal material. When this material is deposited to the surface ocean, either directly or after interception by sea ice, the constituent elements will impact marine biogeochemical cycles. The degree of this impact is a function how much of the given element dissolves from the aerosol. Thus, we explore the fractional solubility of the elements of interest which is described as the percentage of the total amount of an element that dissolves into a solvent. For this project, we have used to solvents meant to approximate distinct natural processes. Taken together we are able to produce an estimate of an aerosol element’s fractional solubility. This data will be available to other researchers and will inform our collective understanding of biogeochemical cycles in the Arctic. This project has supported the professional development of three researchers. Two graduate students received extensive training in analytical techniques using samples from the MOSAiC project. They have applied that training to projects of their own with one having completed their Masters degree and the other working toward a PhD. A postdoctoral researcher participated in Leg 3 of the MOSAiC expedition and has been leading the analytical work. He presented initial results at the 2022 Fall Meeting of the American Geophysical Union. Last Modified: 06/13/2023 Submitted by: Clifton Buck