For the first time in almost half a century, researchers have been able to confirm the great extent of the environmental disaster happening in the Arabian Sea. A new study published on Friday in Geophysical Research Letters revealed a growing "dead zone" in the Gulf of Oman almost the size of Scotland and which is nearly completely devoid of oxygen.
A team from the University of East Anglia (UEA) in England has searched the Gulf of Oman by way of underwater robots and discovered a vast oxygen-less dead zone that is not only larger than anyone expected, but also rapidly expanding.
"Our research shows that the situation is actually worse than feared – and that the area of dead zone is vast and growing," research leader Dr. Bastien Queste, from UEA's School of Environmental Sciences, said in a university news release.
"The ocean is suffocating," he revealed.
According to Queste, the Arabian Sea was already known as "the largest and thickest dead zone in the world." However, the extent of the situation remained unknown for almost 50 years due to piracy and geopolitical tensions, which had rendered the area inaccessible to scientific expeditions.
By working together with Sultan Qaboos University in Oman, the team managed to deploy two underwater robots in the Gulf of Oman for a period of eight months. The robots, known as Seagliders, detected a vast dead zone larger than the size of Scotland with almost no oxygen left.These areas, also called "oxygen minimum zones," naturally occur in some parts of the world and are normally found at depths between 650 and 2,600 feet, notes Queste.
The Seagliders, which are about the size of a human diver, were able to dive even deeper and reach depths of almost 3,300 feet. The underwater robots scoured the ocean for months and covered hundreds of miles, beaming back data on oxygen levels and the ocean mechanics that carry oxygen from one area to another.
Queste points out that these oxygen-less dead zones "are a disaster waiting to happen" and that the situation is continuously worsened by climate change.
"Warmer waters hold less oxygen," Queste explained in the UEA news release, revealing that human activities also impact the growth of oxygen minimum zones.
The dumping of fertilizer and sewage water into the ocean contributes to the dramatic decrease of water oxygen levels, he added.Apart from the decrease in oxygen, on which marine animals and plants depend for their survival, another major problem created by this environmental disaster is the destabilization of nitrogen levels.
Nitrogen is essential for plant growth, the scientist explained, and the absence of oxygen interferes with the chemical cycling of nitrogen, leading to the production of nitrous oxide — a greenhouse gas 300 times more potent than carbon dioxide, Queste said.
Based on the glider findings, his team performed high-resolution computer simulations which revealed dramatic decreases in underwater oxygen levels over the next century and predicted that oxygen minimum zones will continue to increase.
"It's a real environmental problem, with dire consequences for humans too who rely on the oceans for food and employment," said Queste.