May 07, 2018

Gulf of Oman Dead Zone The Size of Florida

The dead zone, caused by a combination of climate change and storm water runoff pollution, is unable to sustain life

Storm water runoff and pollution leads to dead zone in Gulf of Oman

Researchers from the University of East Anglia in Norwich, England, found that the world’s largest ocean oxygen minimum zone (OMZ)—also known as a dead zone—is located in the Gulf of Oman. More chilling, the researchers found that the dead zone is the size of Florida and more than two times larger than Scotland. Similar to the dead zone in the Gulf of Mexico which is caused by nitrogen-rich agricultural storm water runoff from the Midwest farm belt, the OMZ in the Gulf of Oman is likely caused by chemical-laden storm water runoff as well.

Oxygen dead zones are caused when toxic storm water runoff fuels rapid algae growth, which decomposes in the ocean and sucks oxygen from the water, thus making the area uninhabitable for fish and aquatic creatures. Moreover, the absence of oxygen alters the nitrogen cycle, leading to nitrous oxide emissions, a greenhouse gas 300 times more powerful than carbon dioxide. According to The National, climate change and pollution both are contributing factors to OMZ growth. Warmer temperatures cause bacteria to respire more, depleting oxygen supplies, while warmer surface layers reduce the vertical mixing of water and cuts the amount of oxygen absorbed. 

The researchers used remote control submarines, called Seagliders, to map the OMZ in the Gulf of Oman and found it to span 63,700-sq-miles, as reported by Digital Journal. The OMZ has existed for decades, but has not been surveyed since the 1990s. The area has been off-limits to researchers due to political instability and ocean piracy in the region until recently.

Lead Author Dr. Bastien Queste urged the scientific community to respond in a letter published in the journal Geophysical Research Letters

“The ocean is suffocating. All fish, marine plants and other animals need oxygen, so they can’t survive there,” Queste said.