Dive to 144 metres off UAE reveals mysterious 'Mars-like' reef

About a year ago, local fishermen told Simon Nadim that they had noticed something strange on the typically flat seabed off the UAE’s east coast.

Spotted on sonar readings, it appeared to be a shipwreck or coral reef and was about 10 metres tall.

Mr Nadim, the Lebanese founder of the XR Hub diving school in Fujairah, knew he had to solve the mystery in the depths.

After months of preparation, what he found at a depth of 144 metres on November 23 was not a shipwreck, however, but a remarkable formation of corals not typically encountered at that depth in these waters. These types of corals are effectively unstudied in this region and could be home to species not previously found here.

“My first impression was that I had landed on Mars,” said Mr Nadim, who has been diving in the Emirates for seven years and said the dive was a record depth for the UAE. “The site was an underwater hill and composed of a very strange rock formation. This is not something normal.”

The dive was an advanced type known as a technical dive, meaning beyond the limits of traditional recreational activity that tends to stop at a depth of about 40 metres. Divers use a special blend of gases to go deeper and these depths are off limits to only the most experienced.

Mr Nadim, who previously dived to the wreck of the German U-boat 533 that lies about 110 metres down and discovered part of the Ines, an oil tanker that sank and broke in two in 1999, knew this dive would be harder. Exact depths can vary slightly depending on instruments, tides and changes to the sea floor, especially in this region because the seabed is sand.

The team set off from the base at Fujairah at 6am to the location about 30km east to north-east. Mr Nadim was supported by a team that included members from Abu Dhabi Civil Defence. The support team placed gas tanks on the line at required depths to support the lead diver.

Mr Nadim used what is known as a rebreather ― which mixes the gases he breathes as the dive progresses, allowing the diver to be submerged for longer. Underwater scooters are used to move around more easily although divers must be wary of getting entangled in abandoned fishing lines that can litter the seabed.

As Mr Nadim reached the bottom, he entered the silent world ― a twilight zone of dark blue in the depths. Footage of the dive shows him whirring around the coral reef. There was active marine life including small fish and even some barracuda. Several unexplained phenomena occurred, such as clouds of silt being ejected from the coral and a higher water temperature, about 23°C, at the bottom compared with 21°C at 130 metres.

“I’ve never encountered hills at the bottom of the sea,” he said. “There are no mountains on the seabed here. It is a sloping bottom slowly going deeper and deeper. So to have this suddenly go up is strange.

“I left the site with many questions. Could it be a location of thermal springs? Why did the temperature increase at the bottom? What is the nature of the marine life at the bottom? What is causing the clouds of silt ejecting out of the rocks?”

Mr Nadim said the dive was the deepest in the UAE and Gulf region. There is no database of dives yet but he said this was gleaned from contacts in the dive community. By comparison, the deepest dive in the world was one of more than 300 metres in the Red Sea several years ago. Mr Nadim spent 20 minutes on the seabed and a staggering seven hours carrying out decompression stops on the ascent to prevent sickness known as “the bends”, which can be fatal.

“During this time I observed small bubbles coming from the sea floor. I found this weird. Are these thermal springs or vents? An active one would be more visible.”

The footage and photographs of the dive are now being studied by marine biologists and geologists and Mr Nadim is planning more dives there and potentially take samples. One main question is why are corals at that depth in UAE waters ― known as the “mesophotic zone” ― and how old are they?

“While we know of mesophotic reefs occurring in the Red Sea, this is the first evidence that I am aware of for corals being observed at nearly 150 metres depth in eastern Arabia,” said John Burt, an associate professor at NYU Abu Dhabi and an expert in coral reefs.

Prof Burt said while these corals are highly vulnerable they represent a “ray of bright light in the dark era of climate change” because these deep water corals and fish will produce larvae that drift into the shallows and aid recovery of reefs after they suffer bleaching events that occur during heatwaves. “They represent a 'biological insurance' against climate change,” he said.

Prof Burt cautioned that any surveys must be performed very delicately and specimens must be collected in a targeted way to minimise disruption to the ecosystem. “This is a system that has never [previously] had human visitation ― ever ― and we want to maintain that system in as pristine a state as possible,” he said. “It really does represent a natural asset for the Emirates.”