Nanus, Leora听1听;听Williams, Mark W.听2听;听Campbell, Donald H.听3
1听精品SM在线影片
2听精品SM在线影片
3听United States Geological Survey
Acidification of high-elevation lakes in the Western United States is of concern because of the storage and release of pollutants in snowmelt runoff combined with steep topography, granitic bedrock, and limited soils and biota. The sensitivity of 850 lakes to acidification from atmospheric deposition of nitrogen (N) and sulfur was estimated by relating water-quality and landscape attributes in Glacier National Park, Yellowstone National Park, Grand Teton National Park, Rocky Mountain National Park and Great Sand Dunes National Park and Preserve. Water-quality data measured during synoptic surveys (n=151) were used to calibrate statistical models of lake sensitivity. Landscape attributes for the lake basins were derived from GIS including topography, bedrock type, soil type, and vegetation type. Using multivariate logistic regression analysis, probability estimates were developed for acid-neutralizing capacity (ANC), and sensitive lakes were identified. In the case of N deposition, water-quality data included dual isotopes of d15N and d18O of nitrate. Water-quality data collected at 60 lakes during fall 2004 were used for cross-validation and 85% of lakes sampled were accurately identified by the model. Lakes exceeding 60% probability of having an ANC concentration less than 100 microequivalents per liter are located in Rocky Mountain and Grand Teton National Parks, at elevations above 2800m, and greater than 83% of the basin with low buffering capacity bedrock.