Photo 1 (IMAGE) Helmholtz Centre for Environmental Research - UFZ Caption Study site on the Havel River (Germany), one of 72 field experiments worldwide whose data were included in the synthesis. Credit Kristin Ludewig 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.