Scientists discover five new species of black corals living thousands of feet below the ocean surface near the Great Barrier Reef

Many of these corals are branched and look like feathers, fans or bushes, while others are straight like a whip.

Using a remote-controlled submarine, my colleagues and I discovered five new species of black corals living as deep as 2,500 feet (760 meters) below the surface in the Great Barrier Reef and Coral Sea off the coast of Australia.

Black corals can be found growing both in shallow waters and down to depths of over 26,000 feet (8,000 meters), and some individual corals can live for over 4,000 years.

Many of these corals are branched and look like feathers, fans or bushes, while others are straight like a whip. Unlike their colourful, shallow-water cousins that rely on the sun and photosynthesis for energy, black corals are filter feeders and eat tiny zooplankton that are abundant in deep waters.

In 2019 and 2020, I and a team of Australian scientists used the Schmidt Ocean Institute’s remotely operated vehicle – a submarine named SuBastian – to explore the Great Barrier Reef and Coral Sea.

Our goal was to collect samples of coral species living in waters from 130 feet to 6,000 feet (40 meters to 1,800 meters) deep.

In the past, corals from the deep parts of this region were collected using dredging and trawling methods that would often destroy the corals.

Our two expeditions were the first to send a robot down to these particular deep-water ecosystems, allowing our team to actually see and safely collect deep sea corals in their natural habitats.