Stream Hypoxia (IMAGE) Duke University Caption A new study finds that hypoxic dead zones, where dissolved oxygen levels in water drop so low that fish and other animals suffocate, occur in urban streams such as this one in Raleigh, N.C. Credit Duke Univ. 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.