Grant: Alliance Grants

Increasing water color in lakes, called lake browning, is a severe threat to water quality and biodiversity of northern lakes, which are of vital cultural, economic and environmental importance to people. Caused by changes in the soils and vegetation that surround and leach dissolved materials to lakes, the increasing water color is associated with changes in biogenic elements such as carbon, nutrients, mercury, iron and calcium. Balanced concentrations of these elements drive the healthy functioning of lakes, but when imbalanced with higher water color they can lead to decreased drinking water quality, biodiversity losses, and changes in fisheries and recreational use of lakes. This project brings together a complementary set of leading laboratories in Canada, Finland and USA with expertise in elementomes, biogeochemistry, chemistry, and paleolimnology, to develop an improved, integrated understanding of decade long responses of lakes to browning. Specifically, we will develop a tool for measuring and reconstructing changes in elemental pools in lakes, which is based on the elemental composition of subfossil dormant eggs of Daphnia water fleas, and provide novel information on the variability of responses to browning from lakes in different climate zones and for lakes that have become browner for different reasons. We will undertake an analysis of lakes in boreal, subarctic and Arctic landscapes where browning is driven by changes in the deposition of industrial emissions of sulphur and nitrogen compounds, increased precipitation and rising temperatures, or the combination of the two. We will also undertake training, from local knowledge exchange to international graduate and postdoctoral projects.