Lake Sediment Core (image) University of California - Riverside Caption Researcher Peter Homyak is seen here collecting a lake sediment core to study the impacts of air pollution and climate change on alpine lakes of the Sierra Nevada. Credit Sickman Lab, UC Riverside. Usage Restrictions None 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.