Anticipate average dead zone
Researchers say the annual low-oxygen “dead zone” that forms every summer off the coast of Louisiana will be about average size this year.
According to forecast modeling done through research at a number of universities, including LSU and the Louisiana Universities Marine Consortium, and through support from the National Oceanic and Atmospheric Administration, the dead zone will end up covering between 4,633 square miles to 5,708 square miles this summer. NOAA, in a press release Tuesday, said the actual size of the low-oxygen area will be measured later this year with results released in July or early August.
The Advocate reports last year’s dead zone measured 5,840 miles.
The Mississippi River Gulf of Mexico Watershed Nutrient Task Force has long set a goal to reduce the annual size of the “dead zone” to less than 1,930 square miles.
The forecast estimate is based in part on measurements of how much nitrates from fertilizer and other sources flowed down the Mississippi River and into the Gulf of Mexico.
The nitrates that flow down the river enter the Gulf where it feeds small organisms that use up oxygen as they die and fall to the sea floor. Without windy weather from storms or weather fronts to help mix oxygen-rich water at the top with the low-oxygen layers of water at the bottom, low-oxygen conditions can accumulate to a point where levels drop too low to support marine life.
Low oxygen and no oxygen zones are caused by excessive nutrient pollution, primarily from human activities such as agriculture and wastewater, which results in insufficient oxygen to support most marine life and habitats in near-bottom waters. Aspects of weather, including wind speed, wind direction, precipitation and temperature, also affect the size of dead zones.
“We are making progress at reducing the pollution in our nation’s waters that leads to ‘dead zones,’ but there is more work to be done,” said Kathryn D. Sullivan, undersecretary of commerce for oceans and atmosphere and NOAA administrator.
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