The Role of Sediments and Aquatic Plants in the Nutrient Budget of Spirit Lake at Mount St. Helens, WA

Abstract

Introduction:The 1980 eruption of Mount St. Helens caused the bathymetry of Spirit Lake to change drastically, resulting in an increase in surface area and a decrease in average depth. Subsequently, Spirit Lake is experiencing an increase in productivity. This analysis examines concentrations of carbon, nitrogen and phosphorus obtained from sediment samples collected over the summer of 2010, as well as aquatic plant height data, in order to identify sources of the lake's increasing productivity. The results of these analyses will be used as part of a larger nutrient cycling model examining changes in the lake over time.