‘Dead Zones’ Mount Along U.S. Coasts

Low-oxygen “dead zones” in U.S. coastal waters are increasing, according to a report released last week from the President’s Office of Science & Technology Policy. The incidence of dead zones has grown almost 30-fold since 1960, the report says. Efforts to reduce low-oxygen, or hypoxic, waters have made little headway, in part because of population growth and increased development, the report concludes. Dead-zone formation is mainly due to nitrogen and phosphorus runoff from farms, according to the report, and discharges from sewage treatment plants, urban runoff, and air pollution are key contributors, as well. However, hypoxia off the coasts of Oregon and Washington appears to be linked to variations in climate, the report says. This northwestern locale hosts the second-largest seasonal low-oxygen zone in the U.S., after the Gulf of Mexico. The report calls for sound, cost-effective strategies to curb nitrogen and phosphorus pollution and for improved models to determine how low-oxygen areas affect important commercial fish populations.