Tag: dead zone in Gulf of Mexico

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Gulf “Dead Zone” Larger Than Predicted

Credit: National Oceanic and Atmospheric Administration (NOAA)

The polluted “dead zone” in the Gulf of Mexico is much larger than scientists predicted earlier this year. 

An early prediction put the size of this year’s zone at 4,894 square miles. After an investigation cruise, scientists updated the figure to be much larger, 6,334 square miles. 

The four-year average size of this zone is 5,380 square miles. The record size of the zone was 8,776 square miles set in 2017. 

The dead zone is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed. When the excess nutrients reach the Gulf, they stimulate an overgrowth of algae, which eventually die and decompose. This depletes oxygen in the water as they sink to the bottom. 

The resulting low oxygen levels near the bottom of the Gulf cannot support most marine life. Fish, shrimp, and crabs often swim out of the area, but animals that are unable to swim or move away are stressed or killed by the low oxygen. This dead zone flows west from the tip of Louisiana and hugs the coast. 

Most of the pollution that creates the dead zone arrives there by the Mississippi River watershed, which encompasses 40 percent of the continental U.S. and crosses 22 state boundaries.

That’s how Tennessee contributes to the dead zone, sending mainly agricultural runoff (like fertilizer) and treated human waste down the river. All along Tennessee’s river coast — including Memphis — treated human waste is the biggest source of pollution followed by fertilizer, according to data from the United States Geological Survey.  

The federal Mississippi River/Gulf of Mexico Hypoxia Task Force is working to reduce the size of the dead zone to a five-year average size of 1,900 square miles.  

“Through state leadership in implementing nutrient reduction strategies, support from [Environmental Protection Agency – EPA] and other federal agencies, and partnerships with basin organizations and research partners, we will continue to tackle the challenge of Gulf hypoxia,” said John Goodin, director of the EPA’s Office of Wetlands, Oceans and Watersheds.

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2021 Gulf “Dead Zone” Predicted to be Size of Connecticut

Credit: NOAA

Scientists have collected data on this annual dead zone in the Gulf of Mexico since 1985. But for the last four years, scientists with the National Oceanic and Atmospheric Adminstration (NOAA) have focused on the Gulf’s dead zone where oxygen levels are low and predicted its size. 

This year’s zone is smaller than the five-year average of 5,400 square miles and nearly half of the 2017 record zone of 8,776 square miles. But at 4,880 square miles, the zone is not small — it’s comparable to the state of Connecticut’s 4,849 square miles.

The dead zone is primarily caused by excess nutrient pollution from human activities in urban and agricultural areas throughout the Mississippi River watershed. When the excess nutrients reach the Gulf, they stimulate an overgrowth of algae, which eventually die and decompose. This depletes oxygen in the water as they sink to the bottom. 

The resulting low oxygen levels near the bottom of the Gulf cannot support most marine life. Fish, shrimp, and crabs often swim out of the area, but animals that are unable to swim or move away are stressed or killed by the low oxygen. This dead zone flows west from the tip of Louisiana and hugs the coast. 

Most of the pollution that creates the dead zone arrives there by the Mississippi River watershed, which encompasses 40 percent of the continental U.S. And cross 22 state boundaries. That’s how Tennessee contributes to the dead zone, sending mainly agricultural runoff (like fertilizer) and treated human waste down the river. All along Tennessee’s river coast — including Memphis — treated human waste is the biggest source of pollution followed by fertilizer, according to data from the United States Geological Survey.  

(Credit: USGS) Mississippi River at Vicksburg, Mississippi

Memphis now operates under a 2012 federal consent decree after a number of agencies alleged the city illegally allowed its sewer system to overflow into the river. In 2016, the city’s system spilled millions of gallons of untreated wastewater into the Mississippi. The city is now working toward the end of the 10-year Sewer Assessment and Rehabilitation Program (SARP10) program to update the sewer system. 

“Like many other cities, Memphis has an aging wastewater collection and transmission system that consists of buried pipes, manholes, and pumping stations,” Memphis Mayor Jim Strickland says on the SARP10 website. “In fact, parts of our system are more than a century old. Due to age, our sewers have experienced some deterioration.”

The federal Mississippi River/Gulf of Mexico Hypoxia Task Force is also working to reduce the size of the dead zone to a five-year average size of 1,900 square miles.  

“Through state leadership in implementing nutrient reduction strategies, support from [Environmental Protection Agency – EPA] and other federal agencies, and partnerships with basin organizations and research partners, we will continue to tackle the challenge of Gulf hypoxia,” said John Goodin, director of the EPA’s Office of Wetlands, Oceans and Watersheds.

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Gulf ‘Dead Zone’ Smaller This Year But Still Huge

Scientists from Louisiana Universities Marine Consortium collect water samples from the Gulf of Mexico.

The dead zone in the Gulf of Mexico will be “average” this year, scientists said Thursday, and while it’s much smaller than last year’s zone, it’s still about the size of Connecticut.

Pollution from the Mississippi and Atchafalaya rivers spills into the Gulf and promotes algae growth. Algae sucks oxygen from the water, making it uninhabitable for fish and other marine life.That hypoxic zone — or “dead zone” — flows west from the tip of Louisiana and hugs the coast.  

Scientists with the National Oceanic and Atmospheric Adminstration (NOAA) predict the dead zone will be about 5,780 square miles this year, close to the 33-year average (since records began in 1985). It is much smaller than last year’s zone, which covered a record-breaking 8,776 square miles.

“The Gulf’s recurring summer hypoxic zone continues to put important habitats and valuable fisheries at risk,” said Steve Thur, 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.”

NOAA

Last year’s record-breaking dead zone was about the size of New Jersey.

Tennessee contributes to the dead zone, sending pollution — from urban activities, farming, and other sources — down the Mississippi River. The river drains about 1.2 million miles of all or parts of 31 states and two Canadian provinces. Renée Hoyos, executive director of the Tennessee Clean Water Network, said the river drains about one-third of the nation, and the nation uses it as a “sewer.”

“By the time it gets to Memphis, it’s in pretty bad shape, because it’s at the bottom of different sources of pollution that’s come to us from as far away as Montana,” Hoyos said.

Memphis now operates under a 2012 federal consent decree after a number of agencies alleged the city illegally allowed its sewer system to overflow into the river. In 2016, the city’s system spilled millions of gallons of untreated wastewater into the Mississippi.