Study: Nutrient pollution threatens ecosystems
By Tony Barboza, Los Angeles Times
National parks from the Sierra Nevada to the Great Smoky Mountains are increasingly being fertilized by unwanted nutrients drifting through the air from agricultural operations, putting some of the country’s most treasured natural landscapes at risk of ecological damage, a study has found.
Thirty-eight of 45 national parks examined by scientists are receiving doses of nitrogen at or above a critical threshold that can harm sensitive ecosystems, such as lichens, hardwood forests or tallgrass prairie, scientists found.
Scientists looked at nitrogen oxides and ammonia that are released by vehicles, power plants and farms and carried on air currents into national parks, including those in some of the most remote areas of the West.