What is a dead zone?
A dead zone is an area of the sea or a large body of water that’s almost entirely devoid of oxygen. Because of the low-oxygen it does not support any life, hence called the dead zones. Fish, animals and plant life in the zones suffocate as a result of low oxygen levels. Some marine animals may try and swim to other areas which isolate the particular area.
What Forms the Dead Zone?
The main cause of a dead zone is eutrophication, an increase in the chemicals in the water. These increasing chemicals give rise to a lot of algae that deplete the levels of oxygen underwater. Sewage, industrial pollutants containing nitrogen and phosphorous that are left into the sea lead to a development of the dead zones. The growing algae also die and decompose in the water. The bacteria feeding on the decomposition also cause in depletion of the oxygen.
With a warmer climate, the waters are also warm, which reduces the oxygen content. With the human and natural factors combining together, the formation of dead zones rises.
The Dead Zone of Gulf of Oman
There are several dead zones across the oceans on the globe but the one in Gulf of Oman has been known since years. However, the area under the zone is underestimated. “The Arabian Sea is the largest and thickest dead zone in the world. But until now, no-one really knew how bad the situation was because piracy and conflicts in the area have made it too dangerous to collect data,” Dr Bastien Queste from UEA’s School of Environmental Sciences said. “We barely have any data collected for almost half a century because of how difficult it is to send ships there.” The findings of the Seaglider robots have found the worsening state of the ocean. These are remote-controlled submarine like robots that can spend months under the water. They found a strong decrease in the oxygen levels.
Other Dead Zones in the World
There are dead zones in the coastal waters of South America, China, Japan, and New Zealand. A 2008 study counted 405 dead zones worldwide. The second largest dead zone in the world is located in the U.S., in the northern Gulf of Mexico.