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U.S. Fish & Wildlife Service
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TOGIAK: Remote Northern Hemisphere Lakes Show Evidence of Human Generated Nitrogen
Alaska Region, December 14, 2011
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High Lake, Togiak National Wildlife Refuge, Alaska.
High Lake, Togiak National Wildlife Refuge, Alaska. - Photo Credit: Patrick Walsh, USFWS photo

Biologists from Togiak National Wildlife Refuge (Alaska) collaborated with an international team of scientists led by the University of Washington to examine the occurrence of human produced nitrogen in remote lakes. The findings reveal that the impact of human activities since industrialization is evident even in the most remote ecosystems on the planet. This research was published in the international journal Science on December 16th, 2011, and is available at http://www.sciencemag.org/.


Sediments accumulate on lake bottoms over time and contain a record of the atmospheric conditions that occurred in an area. In this study, the investigators collected sediment cores from 36 lakes across the northern hemisphere (including 2 lakes on Togiak Refuge) and determined the ratio of nitrogen isotopes over a dated timeline. Human activities (industrial practices, farming, etc.) produce and elevate nitrogen levels in the atmosphere which can be deposited back on Earth through rain and snow. This study found evidence of increased nitrogen deposition occurring for over a century, since shortly after the Industrial Revolution. Additionally, the rate of change increased during the last 60 years with increasing production of agricultural fertilizers.

Located in southwestern Alaska on the Bering Sea, and isolated 350 miles from the road system, Togiak Refuge is among the most remote of places within the National Wildlife Refuge System. However, this research illustrates that human activity thousands of miles distant can result in measureable effects on otherwise pristine ecosystems.

Contact Info: Patrick Walsh, 907 842 1063, patrick_walsh@fws.gov
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