Lake Coring at Sunday Lake (IMAGE) Northern Arizona University Caption To collect sediment samples from lakes in Alaska, NAU researchers often travel by floatplanes and spend days working from a floating platform, using hand-operated weights to tap collection tubes upward of 20 feet into the lake bottom, such as this one at Sunday Lake. Credit Northern Arizona University Usage Restrictions Photo must be accompanied by above cutline and credit. 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.