Lakes Showing Signs
of Warming Climate

The gradual effects of global warming on the earth’s ecological systems make it challenging to study. But UNL hydroclimatologist John Lenters believes he’s witnessing its impact in action.

Lenters studies how lakes respond to climate change. Whether a lake is frozen in the Arctic or fed by water percolating up from an aquifer in Nebraska’s Sandhills, Lenters is finding the influences of a warming climate.

As the planet warms, the consequences to lakes often mean decreasing water supplies for people, wildlife and ecosystems.

Normally, sediments on lake bottoms draw heat out of the water during the summer and release it in the winter in a heat-flux equilibrium. In the Arctic, however, Lenters found lakes drawing heat into the permafrost most of the year. The National Science Foundation funds this study of changes in Arctic lake dynamics.

"We are witnessing the thawing of permafrost in action in just a year’s worth of data," Lenters said. "As the climate warms, the lake sediments take a lot longer to respond and are out of whack. They’re trying to readjust."

In the Sandhills, lakes draw water from the High Plains Aquifer. Sunny, windy and dry conditions increase evaporation, further taxing the aquifer, a vital resource for agriculture, communities and wildlife.

"We’re measuring the highest evaporation rates of any of the lakes we’re looking at," Lenters said of the Sandhills research. "It seems like this region could potentially be very sensitive to slight variations in climate."

On an island in Lake Superior, Lenters is beginning to measure evaporation rates on the world’s largest freshwater lake.

Although Lenters is primarily collecting field data, he’s also combining lake measurements, such as ice thickness in the Arctic and salinity in Nebraska, with weather and other climatic data to create models to help predict global warming’s impacts on lakes over long time periods.

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Credits

The 2009-2010 Annual Report is published by the
University of Nebraska−Lincoln Office of Research and Economic Development. More information is available
at http://research.unl.edu or contact:

Prem S. Paul
Vice Chancellor for Research and Economic Development
301 Canfield Administration Building
University of Nebraska−Lincoln
Lincoln, Nebraska 68588-0433
(402) 472-3123  •  ppaul2@unl.edu

Writers/Editors:
Vicki Miller, Monica Norby, Ashley Washburn, Elizabeth Banset, Office of Research and Economic Development

Contributing Writers:
Gillian Klucas, Kim Hachiya, Cara Pesek
Some articles are based on earlier stories from University Communications and IANR News Service and written by Kelly Bartling, Troy Fedderson, Sara Gilliam, Sandi Alswager Karstens, Daniel R. Moser, Judy Nelson, Tom Simons,
Steve Smith, Carole Wilbeck

Photography/Illustrations:
Joel Brehm, Brett Hampton, Craig Chandler,
Alan Jackson/Jackson Studios, Greg Nathan,
Bruce Thorson, Robert Cope, Laurence Smith
Historic photos, page 22, courtesy Joyce Clarke Turvey

PDF/Print Design: Sym Labs

Website Design: Joel Brehm