Sitting atop the Colorado Rocky Mountains are the turquoise jewels of the high country - alpine lakes. Because the lakes are typically covered by snow and ice until mid-summer, only a few hearty hikers ever see them. Even so, studies by CU-Boulder scientists and others indicate the lakes are beginning to show the pernicious effects of human activity.

Over the past 20 years, the amount of algae has increased and species distribution has been altered in a number of alpine lakes along Colorado's Front Range, indicating an ecological impact of increased atmospheric nitrogen pollution from automobiles and agriculture in the heavily populated Front Range.

	Diane McKnight (upper right in the middle photo) takes a group of elementary school students on a summer field trip at the Niwot Ridge Long-Term Ecological Research site.

Since 1997, a team of graduate and undergraduate students working with researcher Diane McKnight, a fellow of the University of Colorado at Boulder's Institute for Arctic and Alpine Research and a faculty member in the civil, environmental, and architectural engineering department, has studied alpine lakes in the Green Lakes Valley watershed, which provides about 40 percent of the city of Boulder's water supply.

"This study provides an opportunity for students to experience the thrills of field research in the mountains and learn about connections between (land) development and the natural ecosystems that provide important goods and services, such as our high-quality water supply," McKnight said.

She added that similar trends have also been observed in alpine lakes in Rocky Mountain National Park. The Green Lakes study is part of the Niwot Ridge Long-Term Ecological Research (LTER) project, which is one of 24 North American ecosystem sites where scientists are documenting ecological and climate changes over decades and centuries for the National Science Foundation's LTER programs. McKnight is a co-principal investigator of the Niwot Ridge LTER.

"Hopefully, these long-term studies of alpine lakes will provide a basis for development of resource management strategies, such as stricter air pollution standards, that will protect water quality in the future," McKnight said.

McKnight has been associate director of CU's Mountain Research Station since 1996, and is a co-principal investigator in the McMurdo Dry Valley LTER in Antarctica.