Hypoxic or “dead zone” in Gulf to be average-sized this year

Author: || Published: 6/7/2018 at 10:10am

A twice-as-big-as-Rhode-Island-sized area in the Gulf will be devoid of marine life this summer according to NOAA scientists. The forecast for the hypoxic zone or ‘dead zone’ will be approximately 5,780 square miles.

More from NOAA:

The 2018 forecast is similar to the 33-year average Gulf dead zone of 5,460 square miles and is smaller than the 8,776 square mile 2017 Gulf dead zone, which was the largest dead zone measured since mapping began in 1985.

At 8,776 square miles, this year’s dead zone in the Gulf of Mexico is the largest ever measured. // Courtesy of N. Rabalais, LSU/LUMCON

Even though NOAA is predicting an average dead zone this summer, the dead zone remains three times larger than the long-term target set by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force, a group charged with reducing the Gulf dead zone.

Data source: Nancy N. Rabalais, LUMCON, and R. Eugene Turner, LSU // Courtesy: epa.gov

The Gulf’s hypoxic zone is caused by excess nutrient pollution, primarily from human activities in the watershed, such as urbanization and agriculture. The excess nutrients stimulate an overgrowth of algae, which then sinks and decomposes in the water. The resulting low oxygen levels near the bottom are insufficient to support most marine life.

Studies have also shown a multitude of other impacts associated with high nutrient concentrations within watersheds. Such impacts include high nitrates in groundwater, higher drinking and wastewater treatment costs and wasted fertilizer applications.

“The Gulf’s recurring summer hypoxic zone continues to put important habitats and valuable fisheries at risk,” said Steve Thur, Ph.D., director of NOAA’s National Centers for Coastal Ocean Science. “Although there has been some progress in reducing nutrients, the overall levels remain high and continue to strain the region’s coastal economies.”

Keep in mind this hypoxic zone is, in general, a naturally-occurring phenomenon. The size and breadth of the hypoxic zone is the part that humans contribute to and is the part that fluctuates. For example, there are at least 500 dead zones that have been reported near coastal areas in recent years, up from fewer than 50 in 1950.

You can read more about the history of the hypoxic zone here: https://www.epa.gov/ms-htf/northern-gulf-mexico-hypoxic-zone

You can read about what hypoxia is here: https://www.epa.gov/ms-htf/hypoxia-101


Author of the article:


Nick Lilja

Nick is former television meteorologist with stints in Amarillo and Hattiesburg. During his time in Hattiesburg, he was also an adjunct professor at the University of Southern Mississippi. He is a graduate of both Oregon State and Syracuse University that now calls Houston home. Now that he is retired from TV, he maintains this blog in his spare time.