Researchers (IMAGE) Helmholtz Centre for Environmental Research - UFZ Caption This image depicts Christian Siebert and Tino Rödiger from the UFZ during sampling in the Sink Holes in the Wadi Al-Arab. Credit Photo: André Künzelmann/UFZ 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.