Warming climate causing Alaska lakes to dry up

Fairbanks, Alaska

More than 10,000 Alaskan lakes "shrunk in size or completely dried up" between 1950 and 2002 according to a study published in the Journal of Geophysical Research-- Biogeosciences.

The study says that during this period, "Alaska has experienced a warming climate with longer growing seasons, increased thawing of permafrost, and greater water loss due to evaporation from open water and transpiration from vegetation; yet there has been no substantial change in precipitation."

The study, based on aerial photographs and satellite imagery and conducted by researchers at University of Alaska Fairbanks' Bonanza Creek Long-Term Ecological Research Program, concluded that the reduction and disappearance of Arctic ponds is the result of climate change in Alaska. The scientists, led by Brian Riordan, say that the findings may be "indicative of widespread lowering of the water table throughout low-lying landscapes in Interior Alaska" which could adversely affect the climate-regulating ability of wetlands by exposing carbon in the soil to "aerobic decomposition", resulting in the release of carbon dioxide. The researchers write that the ecosystem changes could impact wildlife populations.

"Alaska is important in terms of waterfowl production, and if you have a lowering of the water table, that could have a potentially huge impact on waterfowl production," said David Verbyla, a co-author of the study and professor at the School of Natural Resources and Agricultural Science at the University of Alaska, Fairbanks.

"This is an issue relevant to flyway management, in terms of all the ducks that might use the Yukon Flats National Wildlife Refuge and overwinter elsewhere, and this is something that goes beyond the refuges in Alaska," said David McGuire, professor of landscape ecology at the Institute of Arctic Biology at the University of Alaska, Fairbanks.

The study found significant declines in subarctic Alaskan ponds and negligible change in the ponds of the Arctic Coastal Plain.
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