Project: GEOTRACES Arctic Section: Collaborative Research: Biogeochemical cycling of particulate trace elements in the western Arctic basin

NSF Award Abstract:
As part of this project, two investigators will participate in the 2015 U.S. GEOTRACES Arctic expedition to determine the trace element composition of different suspended particles in the water column of the Arctic Ocean to identify the sources and scavenging capabilities of these particles. 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. This team of trace element scientists will focus on the measurement of particulate trace elements, which will enable scientists to better estimate the sources of particulate metals to the Arctic Ocean and to better understand their contribution to biological processes. This project will also provide educational opportunities for undergraduate students, K-12 teachers, and the general public.

Particulate trace element distributions, sources, sinks and cycling are predicted to be controlled by physical, biological, anthropogenic and geochemical processes in the Arctic. Furthermore, many trace elements are required nutrients for marine phytoplankton, playing a key role in oceanic primary productivity. However, few integrated oceanographic studies have been conducted to specifically investigate these relationships in this region, despite the changing conditions and global significance of the Arctic. This project will significantly advance understanding of the complete geochemical cycles of a number of trace elements in the Arctic Ocean basin by measuring the concentrations of particulate trace elements in bulk particles collected through the water column and in sediments, as well as in phytoplankton from the upper water column. These measurements will enable scientists to constrain the inputs of particulate elements from rivers, shelves and ice, and to assess the removal of dissolved trace elements via passive scavenging and biological uptake.