Researchers prepared the release of the summer estimation regarding the size of the dead zone off the coast of Louisiana. This year, its surface will be of approximately 5,900 square miles.
The officials say that they have yet failed to succeed in reducing the area. Still, this year its size came back to its average, which means that it will be almost as large as Connecticut.
The US Geological Survey estimated that starting from the beginning of the year almost 146,000 metric tons of nitrate and 20,800 tons of phosphorus were released into the rivers of Mississippi and Atchafalaya.
Scientists believe they found the mechanism behind the formation of the dead zone, even though they are unable to reduce it.
The discovery was made based on the nitrogen and phosphorus measurements in the Mississippi and Atchafalaya rivers.
Algae blooms and microscopic animals feed off the nutrients that come from sewage and farm runoffs, and die. Their corpses descent into the deep, and while decomposing they use up the oxygen from the waters.
The resulting area is called hypoxic zone, because of the dangerously low levels of oxygen. The oxygen in the water is consumed by the decaying algae which thrive over the increase amounts of fertilizers that get dumped into the rivers and off into the ocean.
The lack of oxygen creates an uncomfortable environment for shrimps and crabs, which either die or desert the area.
Thus, the dead zone is negatively affecting fisheries and communities that depend on the aquatic animals.
The only time when the lower water layers lacking oxygen are dispersed is when a storm or a hurricane troubles the Gulf.
Scientists are still trying to figure out what should be done to limit the affected area. Until now, they decided to monitor the hypoxic zone and to create models of its origins, in order to inform the communities and provide them with alternatives.
The dead zone was first measured in 1985, when its size was almost half than it is now.
Last year, the difference between the estimated size and the measured size was of 1,000 square miles. The officials will soon release the estimated size for this year, which should not be larger than the one of the average measurements done in the last five years.
Advocates say that not enough is made in order to reduce the dead zone. Until now, the efforts to reduce the levels of nitrates in the rivers were voluntary. Community representatives and environmental groups say that the government should take stronger measures to reduce the release of substances in the rivers.
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