Researchers have found the second largest "dead zone" in the Gulf of Mexico, about 5,052 sq. miles, which is the size of Connecticut.
Scientists from the U.S. Environmental Protection Agency (EPA) and National Oceanic and Atmospheric Administration (NOAA), surveyed the part of the Gulf of Mexico from July 27 to Aug. 2 and found low oxygen water in the dead zone, or hypoxia area.
In 2013, the dead zone was reported to be 5,840 sq. miles, bigger than what it is now. The dead zone is also smaller than the five-year average of 5,500 sq. miles. The dead zone is also much smaller than the record 8,481 sq. miles, which was reported in 2002.
The first dead zone appeared in the Gulf of Mexico in 1972 and scientists report that they have found the dead zone every year during summer and spring. Scientists have set a target to reduce the size of the dead zone to less than 1,900 sq. miles, but it seems that they are well behind their goal.
Gene Turner, a researcher at Louisiana State University's Coastal Ecology Institute explains that the primary reason that causes a dead zone is excess runoff of nutrients from farms that are located along the Mississippi River, which drains into the Gulf of Mexico.
The nutrients increase algae growth, which ingests oxygen and results in depleted oxygen level in the water. The lack of oxygen does not support marine life but still supports bottom-dwelling shrimps and fish.
"The Dead Zone off the Louisiana coast is the second largest human-caused coastal hypoxic area in the global ocean and stretches from the mouth of the Mississippi River into Texas waters and less often, but increasingly more frequent, east of the Mississippi River," says Nancy Rabalais, Ph.D., executive director of the Louisiana Universities Marine Consortium (LUMCON), who led the survey cruise, which maps the dead zone area.
The number of dead zones on the Earth's water bodies is on the increase and currently, there are over 550 dead zones on the planet. The size of the dead zone area also fluctuates; however, the increase in farming lands in the region along the Mississippi River since the 1970's has also given a growth to dead zones in the Gulf of Mexico.
Researchers say that the annual dead zone mapping cruise is significant as it understands and tracks the progress of the dead zone in the area.
