Scientists Found a Vast, Deep Sea Coral Garden off Greenland’s Coast

Image from benthic sled. Coral garden habitat with a high diversity of animals including sponges, anemones, and feather stars (Photo: ZSL/GINR)
Image from benthic sled. Coral garden habitat with a high diversity of animals including sponges, anemones, and feather stars (Photo: ZSL/GINR)

In the depths of the water just west of Greenland, scientists have discovered a previously unknown coral garden. They described the ecosystem in a new study published in Frontiers in Marine Science on Monday.

The garden sits 487.68 m below sea level, where the pressure is 50 times greater than at the surface. The researchers found it using a low-tech rig called a “benthic sled,” consisting of a GoPro camera, lights, and laser pointers, which they set into special pressure-proof cases, mounted on a steel frame, and hung from their research vessel.

Image: Stephen Long

The team lowered the set-up 457.20 m into the water and recorded video at 18 locations. When they looked back at the footage, they found an expansive garden full of pastel soft corals, sponges, sea stars, anemones, rockfish, shrimps, and snails. At roughly 492 in size, the ecosystem is about the size of Tulsa, Oklahoma.

The seafloor is a very dark place, hence the need for lights on the research rig. The photosynthetic algae that give corals in shallower waters their bright colours can’t survive here. But deep-sea corals can, and so can many other organisms which depend on them for shelter. In roughly 1,200 still images pulled from the footage, the team identified over 44,000 individual organisms.

Photo: ZSL/GINR

The researchers’ rig cost just $US5,000 ($7,296), which is a steal at a fraction of the cost of cost of other deep-sea sleds. “A commercially available deep-sea [remote operated vehicle] would cost at least six figures, and many models would go into seven figures,” Stephen Long, lead scientist and a PhD researcher at University College of London and the Zoological Society London, told Earther. “This is a huge barrier to research…it means that there are fundamentally only a small pool of researchers and institutions that can undertake this kind of research, which is a shame.”

The deep sea is one the planet’s least understood environments — just one-fifth of the seafloor is mapped — and the prohibitive costs of exploration are a major reason why. So the researchers hope their DIY system will make deep sea research more accessible to scientists around the world.

Though seafloor habitats aren’t well understood, they are crucial to the economy of Greenland. The country’s fisheries constitute more than 90% of exports and are a crucial source of both jobs and food.

In the future, the biodiverse habitat could be at risk because of bottom trawling (a method of fishing that involves dragging nets across the sea floor) and deep sea mining.

“Typically, deep-sea species are characterised by traits, including slow growth, late-maturity, and longevity, which can render populations, communities, and habitats vulnerable to exploitation and disturbance,” said Long. “These characteristics mean that physical disturbance, such as by bottom trawling, can have significant impacts on deep-sea habitats and recovery can take a very long time, in the order of decades or even centuries.”

So the authors call for the garden they discovered to be protected as a Vulnerable Marine Ecosystem under United Nations guidelines. They are also working with officials from the Greenland government and the local fishing industry, who have been receptive to putting protections for the garden in place. This “fragile, complex, and beautiful habitat,” Long said, must be protected.