This year’s “dead zone” in Gulf of Mexico, where oxygen is too scarce to support marine life, is predicted to be one of the area’s largest in history, according to a report released by National Oceanic and Atmospheric Administration (NOAA) on Monday.
“Dead zones” occur cyclically in the Gulf and are caused by excessive nutrient pollution that makes its way from agricultural sites into water bodies. This year, it is expected to grow to roughly 7,829 square miles, or about the size of Massachusetts, the NOAA said. However, a similar study released by the Louisiana State University (LSU) last week, predicts the zone will be even bigger than that, reaching approximately 8,717 square miles, about the same size as New Jersey.
Both estimates put the size of this year's "dead zone" just slightly behind the record of 8,766 square miles observed in 2017. Still, the predictions exceed the five-year average of 5,770 square miles by a hefty amount.
“We think this will be the second-largest, but it could very well go over that,” Nancy Rabalais, marine ecologist and co-author of the LSU report, told CNN.
The NOAA blames unusually heavy spring rainfalls and enormous amounts of pollutants in rainwater runoff for the alarming forecast.
Nitrogen and phosphorus from fertilizers are carried by rainwater into the Gulf of Mexico where they encourage the growth of excessive amounts of phytoplankton (microscopic algae) blooms. These eventually die and sink to the bottom of the Gulf, where, as they decompose, they eat up the water’s oxygen supply. The low oxygen levels then threaten all living organisms in the water body — creating a "dead zone" — including fish, shrimp, and crabs, both an important source of food and income for people in the area.
Water from 41% of the US drains into the Mississippi River, which eventually joins the Gulf of Mexico. The US Geological Survey reported that the average river discharge carried 156,000 metric tons of nitrate and 25,300 metric tons of phosphorus into the Gulf this past May alone — 67% higher than the long-term average over the past four decades.
While little can be done to reduce the expected size of the "dead zone" and reverse the impact of this nutrient runoff on the Gulf this year, farmers can take action to prevent similar destruction in the future. Switching to eco-friendly and natural fertilizers can help reduce the amount of nitrogen and phosphorus at risk of entering the Gulf. Farmers can also plant more crops like wheat grass that have longer roots and can retain soil nutrients more easily.
"It is all a part of how we treat our ecosystem and our consumptive nature," Rabalais said.
"It's all connected to our carbon footprint and the nitrogen used in farming and used to feed animals that we don't need to eat. It is all tied together with the global economy and now tariffs and the way subsidies are given to farming."