It seems like every day we’re learning something new about the oceans. Sometimes we discover new sea life or new ways that animals communicate with each other under water, other times, however, we come across disturbing features like this one…
Recently, robots exploring the depths of the Gulf of Oman have discovered a “dead zone” the size of Scotland!
“Our research shows that the situation is actually worse than feared – and that the area of dead zone is vast and growing,” said Dr Bastien Queste, who led the research published this week in Geophysical Research Letter. “The ocean is suffocating.”
“Of course all fish, marine plants and other animals need oxygen, so they can’t survive there,” Dr Queste continued. “It’s a real environmental problem, with dire consequences for humans too who rely on the oceans for food and employment.”
Researchers have known about the dead zone in the Gulf of Oman for a while but, until now, have been unable to fully investigate it. Between the geopolitical instability of the region and the frequency of pirate attacks, research ships have been unable to do any investigations for the last 50 years.
So, as a solution, scientists form the University of East Anglia along with researchers from Oman’s Sulta Qaboos University decided to make the use of Seagliders to carry out the investigation.
Seagliders are underwater robots that can collect data autonomously and send it back via satellites. The robots surveyed the region in the gulf down to 1,000 meters for eight months, measuring oxygen levels and the underwater currents that move oxygen around at these deep levels.
After all the data had been collected, scientists were stunned at the results. Yes, they knew there was a dead zone in the Gulf of Oman, but thanks to the Seaglider, they were able to see just how big it was.
It revealed that the dead zone that sits between 200 and 800 meters (650 to 2,620 feet) beneath the surface is enormous, much larger than they thought it would be. It is currently comparable to the size of Scotland, making it the largest and thickest ocean dead zone in the world. And it’s growing.
This is not only an issue for any animals that want to live there, but has a knock-on effect on how other vital nutrients cycle through the oceans. For example, the researchers note how when oxygen is absent, it impacts how nitrogen moves through the water, too. This has a negative effect on plants, but can also lead to the production of nitrous oxide, which is roughly 300 times more potent than carbon dioxide.
Predictions show that over the next century, this zone is expected to grow. This means that the fishing industry needs to pay serious attention and change their management practices to maintain sustainability in the region now.
Poorly oxygenated water can lead to huge fish kills like the one that took place in the Gulf in the summer of 2,000. At that time, Omani officials were worried that a toxic algae was responsible for the deaths, but satellite imagery helped them determine that it was due to poorly oxygenated water.
The Seaglider expedition has confirmed that to be true.
The original source for this story is the Geophysical Research Letter.