Determining Critical Loads of Nitrogen Deposition in the Pacific Northwest

Washington (Alpine Lake Wilderness & Mt. Rainer)

Determining Critical Loads of Nitrogen Deposition in the Pacific Northwest

Jasmine Saros

August 2008

Paleolimnological studies in the Pacific Northwest have suggested possible acidification effects of nitrogen (N) and sulfur (S) deposition on alpine lakes in this region, but have been unable to generate a critical load at which these effects occur. In this study, we conducted a series of microcosm experiments in two sub-alpine lakes situated in the Cascade Mountain range in an effort to define critical loads of N to this region. We are also analyzing sedimentary diatom profiles from the two study lakes to assess whether diatom communities in these lakes have already responded to atmospheric deposition.