NEW ORLEANS (CN) – In an annual prediction of the size of the Gulf of Mexico’s “dead zone,” scientists this week said this summer’s will be the third-largest ever: roughly the size of New Jersey.
This year’s dead zone should be twice the usual size, Louisiana State oceanographers R. Eugene Turner and Nancy Rabalais wrote in “2017 Forecast: Summer Hypoxic Zone Size, Northern Gulf of Mexico.”
Even during a usual year, the dead zone in the northern Gulf of Mexico is the largest in North America and the second largest in the world, according to data collected by environmental groups. The size of the dead zone peaks annually in July.
The dead zone in the Gulf has been monitored for the past 32 years. It stretches from the mouth of the Mississippi River into Texas and is created each year by low oxygen levels in water, or hypoxia.
Hypoxia, or a strangulation of oxygen from the water by overgrowth of algae, largely created by phosphates and other minerals in agricultural runoff and waste water treatment flowing into the Mississippi River, creates patches of water that are basically uninhabitable.
Excess nutrients in the waters flowing into the Gulf from the river stimulate an overgrowth of algae that in turn sinks into the water to decompose. The resulting decomposition sucks the oxygen from the water, rendering it uninhabitable for fish and other marine life.
“The Gulf Dead Zone may also slow shrimp growth, leading to fewer large shrimp,” the National Oceanic and Atmospheric Administration, which funded the study, said in a statement. “This could mean higher costs of large shrimp at the marketplace and an economic ripple effect on the Gulf shrimp fisheries.”
The NOAA-sponsored yearly forecast uses data from the U.S. Geological Survey related to nutrient runoff and river discharge.
This year’s large size prediction is based mainly on May stream flows, which carried higher than average nutrients and were roughly 34 percent above the long-term average, according to the report.
The USGS estimated that 165,000 tons of nitrate — roughly 2,800 train cars of fertilizer — plus 22,600 metric tons of phosphorus flowed down the Mississippi and Atchafalaya Rivers in May.
To help reduce nutrient runoff, NOAA provides farmers, the bulk of whom are on Midwest farms on lands that drain into the Mississippi or its tributaries, with NOAA Runoff Risk Advisory Forecasts, which suggest when to avoid applying fertilizers to croplands.
In 2008, environmental advocacy groups headed by New Orleans-based Gulf Restoration Network filed a petition asking the U.S. Environmental Protection Agency to issue standards for states along the Mississippi River.
Three years later the EPA denied the petition, saying that though it agrees “nutrient loadings to the Mississippi River and its tributaries are both harming upstream water quality and contributing significantly to hypoxia … in the Gulf of Mexico” it “does not believe that the comprehensive use of federal rule-making authority is the most effective or practical means of addressing these concerns at this time.” This according to a 2011 federal lawsuit filed by the Gulf Restoration Network and 10 other environmental groups from around the country.
The groups said their petition “submitted voluminous evidence to EPA that excessive nitrogen and phosphorous pollution from states throughout the Mississippi River Basin and Northern Gulf of Mexico has devastating impacts on water quality and the ability of waters to support their designated uses, both in the states themselves and in downstream waters.”
They said their petition documented “how excessive nitrogen and phosphorous pollution in the Mississippi River Basin and northern Gulf of Mexico has caused a large zone of hypoxia (i.e., a low oxygen ‘dead zone’) to develop in the northern Gulf of Mexico.”
The 2007 congressional Energy Independence and Security Act calls for the production of 36 billion gallons of renewable fuels by 2022, including 15 billion U.S. gallons of corn-based ethanol.
The plan would triple not just ethanol production, but corn production, which in turn would ramp up nitrogen production through runoff.
A March 18, 2008, report from the National Academy of Sciences showed that increased corn production to meet the goal of 15 billion gallons would increase nitrogen loading in the dead zone by 10 percent to 18 percent.
As a result, nitrogen levels would be twice those recommended by the Mississippi Basin/ Gulf of Mexico Water Nutrient Task Force. The task force said a 30 percent reduction of nitrogen runoff would be needed to shrink the dead zone.
If this year’s dead zone comes close to the latest estimate, it will be five times the size of the goal of the Hypoxia Taskforce, according to the Gulf Restoration Network.
“A Dead Zone that is predicted to be five times the goal of the Hypoxia Taskforce is a wake-up call. If we are going to fix the Dead Zone, we need a combination of strong pollution protections, dedicated funding, and corporate accountability,” Matt Rota, senior policy director for the Gulf Restoration Network said in a statement.
Rota called this year’s prediction “disheartening, to say the least, especially in the light of the Trump administration’s attempts to dismantle our environmental laws. We should be strengthening efforts to reduce dead zone-causing nitrogen and phosphorus pollution that flows into the Gulf from industrial agricultural fields, not rolling back protections.”