Tipping-point detection (IMAGE) Duke University Caption Found in lakes and rivers worldwide, single-celled creatures like these Paramecium bursaria can both eat and photosynthesize. Microbes like this play a double role in climate change, releasing or absorbing carbon dioxide -- the heat-trapping greenhouse gas that is the primary driver of warming -- depending on whether they rely on an animal-like lifestyle or a plant-like lifestyle. Credit Daniel J. Wieczynski, Duke University Usage Restrictions Please credit Daniel J. Wieczynski, Duke University License Original 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.