The new analysis published in Geophysical Research Letters has uncovered a dramatic boost in the size of the Sea of Oman’s dead zone or oxygen minimum zone (OMZ), an observation that heralds poor news for the region’s aquatic life – and possibly our atmosphere, stated the report.
The dead zone was confirmed by underwater robots known as Seagliders – which have been capable to gather information in places of water previously inaccessible due to the piracy and geopolitical tensions.
The robots are about the exact same size as a tiny human diver, but can attain depths of 1,000m and travel the ocean for months, covering thousands of kilometres.
Two gliders have been deployed in the Sea of Oman, a strip of ocean sandwiched in between India, Iran and Oman, and an crucial gateway into the Persian Gulf, for eight months. They communicated by satellite to construct an underwater image of oxygen levels, and the ocean mechanics that transport oxygen from a single region to an additional.
Where they anticipated some oxygen, they discovered an region bigger than Scotland with nearly no oxygen left. The analysis was led by Dr Bastien Queste from the University of East Anglia’s School (UK) of Environmental Sciences and College of Agricultural and Marine Sciences at the Sultan Qaboos University.
Dr Queste mentioned, “Dead zones are places devoid of oxygen. In the ocean, these are also identified as ‘oxygen minimum zones’ and they are naturally occurring in between 200m and 800m deep in some components of the globe.
“They are a disaster waiting to happen – made worse by climate change, as warmer waters hold less oxygen, and by fertiliser and sewage running off the land into the seas. 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.”
He mentioned that barely any information has been collected for nearly half a century simply because of how tough it was to send ships there. “Our research shows that the situation is actually worse than feared – and that the area of dead zone is vast and growing. The ocean is suffocating. Of course all fish, marine plants and other animals need oxygen, so they can’t survive there. It’s a real environmental problem, with dire consequences for humans too who rely on the oceans for food and employment.”
Another issue is that when oxygen is absent, the chemical cycling of nitrogen – a crucial nutrient for plant development – modifications drastically. Nitrous oxide, a greenhouse gas 300 occasions much more potent than CO2 is made, Dr Queste mentioned.
Computer simulations of ocean oxygen show a reduce in oxygen more than the subsequent century and expanding oxygen minimum zones. However, these simulations have a tough time representing tiny but extremely crucial functions such as eddies which effect how oxygen is transported.
The team combined their Seaglider information with a extremely higher-resolution pc simulation to decide how oxygen is spread about the north-western Arabian Sea all through distinct seasons and the monsoons.
They discovered that the dead zone moves up and down in between seasons, causing fish to be squeezed in a thin layer close to the surface. “Management of the fisheries and ecosystems of the western Indian Ocean over coming decades will depend on better understanding and forecasting of oxygen levels in key areas such as the Gulf of Oman.”
Information Source: Muscat Daily