As predicted, the low-oxygen “dead zone” in the Gulf of Mexico is larger than average this year, said the National Oceanic and Atmospheric Administration on Thursday. At 6,705 square miles — or roughly the size of New Jersey — this year’s dead zone is more than three times the size of the target set for 2035.
The dead zone appears each summer as the result of nutrient runoff from cities and farmland in the Mississippi-Atchafalaya River Basin that stimulates an overgrowth of algae, drives away fish and shrimp, and can affect commercial fishing. Water volume and phosphorus runoff were above average this spring, while nitrate runoff was below average.
“It’s critical that we measure this region’s hypoxia as an indicator of ocean health, particularly under a changing climate and potential intensification of storms and increases in precipitation and runoff,” said Nicole LeBoeuf, a NOAA official. “The benefit of this long-term dataset is that it helps decision-makers as they adjust their strategies to reduce the dead zone and manage impacts to coastal resources and communities.”
The measurements assist the work of the interagency Hypoxia Task Force, created in 1997 with federal, state, and tribal members, with the goal of mitigating the size, severity, and duration of the dead zone. Its goal is to reduce the dead zone to 1,900 square miles by 2035 through such steps as state-written nutrient management strategies.
In June, NOAA researchers forecast a larger-than-usual dead zone, and this year’s is the 12th biggest in 38 years of monitoring. The five-year average is 4,298 square miles. Last year, the dead zone was 3,058 square miles.