Jonathan B. Martin, Ph.D. - US grants

Ice sheets have advanced and retreated across approximately 15% of Earth?s land surface over the past three million years. This glacial cycling produces fine-grained sediments that are easily altered by chemical reactions. As glacial retreat exposes landscapes, ecosystems develop, sediments react, and stream water compositions change. In southwestern Greenland, streams draining glacial meltwater and non-glacial streams separated from glacial meltwater discharge similar amounts of water relative to their drainage areas, but because of distinct chemical compositions, they deliver differing amounts of greenhouse gases to the atmosphere and nutrients to coastal ecosystems. These differences may affect climate, ecosystems, and people, highlighting the need for effective communication of glacial environmental changes to the public. Developing effective communication skills is an integral part of this interdisciplinary study to evaluate how biological, geochemical, and hydrologic processes control stream water composition as glaciers retreat. This insight will enhance evaluations of the effects from past glacial retreat and responses to future Arctic warming. Project results will be shared through environmental civics, a component that will improve researchers? science communication and leadership skills.

Sediment compositions, exposure age, plant and microbe colonization, water availability, and stream-landscape connections are hypothesized to vary systematically across periglacial watersheds and thus control weathering extent, stream geochemistry, and solute and gas fluxes. This hypothesis will be tested in watersheds stretching from the Greenland Ice Sheet to the coast over two melt seasons by an interdisciplinary group of U.S. and Greenlandic researchers who will a) measure non-glacial stream discharge, solute and gas concentrations and fluxes, microbial community structures, plant community distributions, carbon and nutrient cycling, and radiogenic isotopes in stream and bedload sediment; b) maintain automated weather observations, dust collection, and stream chemistry loggers; and c) perform stream dosing experiments. These data will reveal feedbacks between weathering extent, ecosystem characteristics, biogeochemical processes, and stream chemistry and their controls on solute and gas fluxes from periglacial watersheds. In collaboration with Greenlandic colleagues, the results will seed environmental civics plans to develop and implement environmental science curricula at levels appropriate to Greenlandic high schools through a teacher-education program and to create educational materials for tourism in Greenland, Greenlandic secondary schools, and the Arctic Technology Center.

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.