A team led by an environmental scientist at the University of California, Riverside has conducted research on lakes in the Sierra Nevada -- the most sensitive lakes in the U.S. to acid rain, according to the Environmental Protection Agency -- and described human impacts on them during the 20th century. The conclusion is the overall news is good: Air quality regulation has benefited aquatic ecosystems in the Sierra Nevada; controlling air pollution is benefiting nature in California.
http://www.sciencedaily.com/releases/2014/09/140904131609.htm