In this project, a group of investigators participating in the 2015 U.S. GEOTRACES Arctic expedition will characterize and quantify the role of sea ice as a repository and transporter of trace metals and radioisotopes in the Arctic Ocean. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. Working alongside a multi-institutional team of ocean trace element experts, the sea ice group will focus its attention on the importance of ice as a reservoir that can accumulate trace elements in one locale and release them in another. This project will also provide for the training and support of at least one graduate student at the University of Alaska Fairbanks Campus as well as multiple extramural public educational initiatives for local communities (including indigenous populations).
The U.S.GEOTRACES Arctic section will traverse waters impacted by sea ice processes, and exhibiting significant chemical and biological gradients. Sea ice of various ages and provenance will be encountered along the transect, presenting a unique opportunity to characterize trace elements of interest in sea ice with differing histories. The distribution of trace elements of interest in Arctic sea ice has not yet been determined, but it is expected to vary widely, and this study will investigate factors important in determining this variability, and thus important in the transport and distribution of trace elements in the Arctic environment. Access to ice floes will allow trace-metal-clean sampling of atmospheric deposition within snow cover, and characterization of surface waters in contact with sea ice. The project will involve collection of trace-metal-clean samples from the sea ice environment to make high-resolution measurements of dissolved and particulate key trace elements from snow, sea ice and seawater underneath the ice, and to determine sea ice physical, and ancillary chemical characteristics in order to contribute towards the quantification of trace element input to the Arctic Ocean. Samples from the sea ice environment will be collected and homogenized for distribution to the scientific community. In fact, the development of a trace metal clean ice corer by the sea ice group will facilitate the characterization of sea ice chemistry, putting them in a unique position to collect, and distribute sea ice samples to the GEOTRACES community.
