Scientists discover new species of black corals near the Great Barrier Reef

Subject :Environment

New species of Black corals-

Using a remote-controlled submarine, researchers at Smithsonian Institution, Washington, discovered five new species of black corals living as deep as 2,500 feet (760 metres) below the surface in the Great Barrier Reef and Coral Sea off the coast of Australia.
In the past, corals from the deep parts of this region were collected using dredging and trawling methods that would often destroy the corals.

About Black corals-

Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals.
These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive).
Antipatharians are a cosmopolitan order, existing at nearly every location and depth, with the sole exception of brackish waters.
However, they are most frequently found on continental slopes under 50 m (164 ft) deep.
Though they have historically been used by Pacific Islanders for medical treatment and in rituals, their only modern use is making jewellery.

Difference between corals and black coral-

Black corals differ from stony corals, another order of hexacoral, by having a flexible skeletons made of protein and chitin, a fibrous substance that makes up a majority of exoskeletons of arthropods and fungi cell walls.
This compound allows them to move in the current, unlike stony skeletons with their rigid frames.
The compound of black coral skeleton serves another function, as a record keeper.
Their skeletons grow, similar to tree rings, cataloguing changes in their environments and allowing us to see how oceans of the past may have been composed.

Characteristics of black corals-

Black corals can be found growing both in shallow waters and down to depths of over 26,000 feet (8,000 metres), 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.
Black corals are filter feeders and eat tiny zooplankton that are abundant in deep waters.
A black coral reproduces both sexually and asexually throughout its lifetime.
Black corals act as important habitats where fish and invertebrates feed and hide from predators in what is otherwise a mostly barren sea floor.
Among the many interesting specimens were five new species – including one that was found growing on the shell of a nautilus more than 2,500 feet (760 metres) below the ocean’s surface.

Threats-

They are not listed in the IUCN Red List.
Black corals have been declining in numbers and are expected to continue declining due to the effects of poaching, ocean acidification and climate change.