Gas-Tracer Experiments (IMAGE) Proceedings of the National Academy of Sciences Caption These are gas-tracer experiments in the field to investigate methane turnover in termite mounds. Credit Image courtesy of Philipp A. Nauer. 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.