A huge ‘dead zone’ in the Gulf of Oman is growing in size, according to research scientists who predict the oxygen-scarce area is dangerous than previously thought and poses a threat to the ecosystem. Back in the 1960s, researchers have discovered the Dead Zone in the Arabian Sea, found in the Gulf of Oman, a water area which is essentially lacking oxygen, totally. The ocean is suffocating.
As of now, the dead zone in the Arabian Sea is the world’s largest Oxygen Minimum Zone (OMZ). Approximately the size of Scotland or Florida, the dead zone roughly covers the complete Gulf of Oman, which borders Iran, Oman, Pakistan and the United Arab Emirates.
A dead zone is a segment of the sea or a wide body of water that’s almost fully devoid of oxygen. The low-oxygen areas are called dead zones as they can’t support marine life any longer. Fish, animals and plant life in the zones choke as a result of depressed oxygen levels, while some marine life succeeds to swim away from the area, leaving it blank.
Aquatic and marine dead zones can be created by an expansion in chemical nutrients (certainly nitrogen and phosphorus) in the water, scientifically termed as eutrophication. These chemicals are the primary building pieces of single-celled, plant-like organisms that exist in the water column, and whose growth is restricted in part by the accessibility of these materials.
Scientists began seeing increasing fields of dead zones in the 1970s. In 2008, 405 dead zones throughout the world were recorded by Sweden’s Göteborg University. The occurrence of the Gulf of Oman dead zone has been known for about 50 years, but the size of the area has only recently been verified thanks to the use of marine robots, called Seagliders.
The data collected revealed that in the regions where it was expected that there would be some amount of oxygen, the levels are now almost zero. Scientists unveiled an area of about 165,000 square kilometers, about twice the area of Scotland or as big as Florida.
“The Arabian Sea is the biggest and thickest dead zone in the world. But till date, no-one truly knew how serious the condition was because piracy and disputes in the area have made it too risky to collect information,” Dr. Bastien Queste from UEA’s School of Environmental Sciences said. “We hardly have any data obtained for almost half a century because of how challenging it is to send ships there.”
The remote-controlled submarines are the size of a small man and can spend months underwater at 1km. They were used by research scientists from the University of East Anglia to the Gulf of Oman for eight months.
The team’s verdicts have now been published in Geophysical Research Letters. They obtained a strong drop of oxygen in the troubled zone compared to pre-1990 levels and also mapped how the oxygen is spread around the area over several seasons.
“Our research shows that the situation is actually worse than feared and that the area of the dead zone is vast and growing. The ocean is suffocating,” Queste said.
Dead zones can befall very naturally, but also develop as a result of extreme nutrient pollution from human exercises, the National Oceanic and Atmospheric Administration reveals. Many chemical, physical and biological constituents connect to form dead zones, but nutrient pollutions are the chief culprit. Nitrogen and phosphorus in fertilizers work into the water and then act as nutrients which feed algae.
The algae ultimately die and decompose in the water. This then serves bacteria which absorb oxygen nearby them, exhausting the supply. Climate change has intensified the issue, as hotter waters hold less oxygen.
The Gulf of Mexico is base to one of the biggest dead zones, which befalls each spring when farmers fertilize their land and the rain cleanses the fertilizer into streams and into the sea. An area in the Baltic Sea is another massive dead zone.
Dead zones are “a real environmental dilemma, with terrible outcomes for humans too who rely on the oceans for food and work.” Guete said. More stressing is the fact that dead zones generate nitrous oxide, which is more damaging to the atmosphere as compared to carbon dioxide.
Limnologist Dr. David Schindler, whose research at the Experimental Lakes Area headed for the banning of dangerous phosphates in detergents, reminded about algal blooms and dead zones,
“The fish-killing blossoms that destroyed the Great Lakes in the 1960s and 1970s haven’t gone beyond; they’ve traveled west into a dry world in which people, industry, and agriculture are frequently taxing the quality of what little freshwater there is to be had here….This isn’t merely a field problem. The global development of dead zones generated by algal blooms is increasing rapidly.”
Scientists caution that computer simulations of ocean oxygen reveal levels will shrink over the next 100 years, with oxygen minimum zones growing. The next step for research scientists is to further examine to learn all of the contributory reasons of the expanding dead zone. Massive Dead Zones are taking over many parts of the Arabian Sea, and researchers have to find a way out.