Science objectives

As glaciers flow across landscapes, they grind bedrock into fine sediments. When these sediments come into contact with water they are altered by chemical reactions that occur in streams on top of the glaciers, beneath the glaciers, and as water flows across landscapes that were at one time glaciated, but were exposed during glacial retreat.  Two types of streams flow across the deglaciated landscapes in the study area—those running from ice sheets, and those autonomous of ice sheets.  Both drain significant volumes of water, but because they have distinct chemical compositions, they can differ substantially in biodiversity, the greenhouse gases (GHGs) they release, and the nutrients they carry to the ocean.

The objective of the SILA project is to use a multidisciplinary approach to develop a holistic understanding of feedbacks that control weathering, hydrological, ecological, and biogeochemical processes across the different types of streams draining the glacial and post-glacial landscapes.  Disciplines represented by our group include ecology, hydrology, botany, microbiology, geology, and chemistry.  We intend to test several hypotheses about causes of and controls on the chemical compositions of streams.  Through this hypothesis testing, we hope to be able to understand how environments changed as ice sheets retreated to expose around 15% of Earth’s continental landscapes since the Last Glacial Maximum about 20,000 years ago, and how the environment may change as the Arctic warms in the future.