Fieldwork (IMAGE) University of Copenhagen - Faculty of Science Caption The fieldwork was conducted during the winter because the frozen lake surface provided the researchers with a solid (but freezing) platform for drilling into the sediment. Credit Mikkel Winther Pedersen Usage Restrictions None 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.