A hidden coral world, deep in the oceans

A hidden coral world, deep in the oceans

The deep ocean reveals its secrets.

What do you think these people are going to study?

Johnston Sea Link Manned Submersible

Sharks? Whales? Clownfish? They're researching this:

Where do you think these corals are found? The Great Barrier Reef? The Caribbean?

When you hear the world coral, you immediately think of the colourful reefs found in tropical waters, some of the most studied and loved ecosystems on earth. It may surprise you to hear that corals aren't just found in the tropics. The cold, dark waters of the deep-ocean are home to cold-water coral reefs, which just like tropical reefs extend over vast distances and form large 3D structures. The corals in the video are found 290 metres deep in the seas around Norway.

Cold water coral and crabs

Cold-water coral and crabs

The cold-water corals that form these reefs are actually animals, like their warm-water coral relatives. These animals live in a fixed place and feed by catching prey from the surrounding water using their stinging tentacles. These corals are usually found at huge depths, between 200-400 metres. The lack of light and cool temperatures means they grow really slowly.

Until recently, scientists knew very little about these corals, as they had to rely on dredging and trawling to bring samples back to the surface. Nowadays, we can use advanced technology like submersibles to visit the deep sea, and see the corals in their natural environment. These submersibles can either be manned, so people can dive down to the corals, or remotely operated, where machine robotic submersible is controlled from a ship, and can collect a wide variety of different data, including videos, photos and actual coral samples. This video shows a remote operated vehicle, used to research coral:

Sadly many of these surveys have shown that cold-water coral habitats have been damaged by bottom trawling for deep-sea fish. If these large trawls roll across corals they cause tremendous damage smashing reef structures and breaking delicate corals that will take hundreds or thousands of years to re-grow. Corals are also vulnerable to climate change. Around a third of the carbon dioxide released as we burn oil and gas has dissolved in the oceans. When carbon dioxide dissolves in water it forms carbonic acid. This means that the oceans are not only becoming warmer but are also becoming more acidic. Cold-water corals are among the most vulnerable species to ocean acidification.

To find out more about cold-water corals and the threats they face, visit www.lophelia.org. After watching spectacular videos of deep-sea corals, and reading more about these amazing creatures, you can test your knowledge in fun quiz games with Eunice the worm, solve intricate jigsaw puzzles or download unique screensavers with rarely-seen images of cold-water corals.

Thanks to Dr Laura Wicks from www.lophelia.org for this article.