Float Plane on Lake (IMAGE) University of Washington Caption Researchers take a quick break on the shore of one of the lakes sampled in the Yukon Flats National Wildlife Refuge in Alaska. Credit David Butman/University of Washington Usage Restrictions Photo credit required. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.