As the ‘dead zone’ expands

In the waters of the Arabian Sea, a vast “dead zone” the size of Scotland is expanding and scientists say climate change may be to blame.

In his lab in Abu Dhabi, Zouhair Lachkar is labouring over a colourful computer model of the Gulf of Oman, showing changing temperatures, sea levels and oxygen concentrations. His models and new research unveiled earlier this year show a worrying trend.

Dead zones are areas of the sea where the lack of oxygen makes it difficult for fish to survive and the one in the Arabian Sea is “is the most intense in the world,” says Lachkar, a senior scientist at NYU Abu Dhabi in the capital of the United Arab Emirates.

Lachkar and other researchers are worried that global warming is causing the zone to expand, raising concerns for local ecosystems and industries including fishing and tourism.

The discovery was made possible by the use of robotic divers, or “sea gliders”, deployed in areas researchers could not access – an undertaking by Britain’s University of East Anglia in collaboration with Oman’s Sultan Qaboos University.

At NYU Abu Dhabi, Lachkar explains the Arabian Sea dead zone appears to be stuck in a cycle where warming seas are depleting the oxygen supply which in turn is reinforcing the warming.

This, he says, “can be very scary for climate”.

The coastal hubs and the populations beyond them will be affected by further expansion of the dead zone.

“When oxygen concentration drops below certain levels, fish cannot survive and you have massive death,” says Lachkar. “Fishing is an important source of revenue and it’s directly impacted by the oxygen,” he said.

Even coral reefs and, by extension, tourism could be affected, added Lachkar.AFP


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