Context –

Researchers from the Smithsonian Institution in Washington used a remote-controlled submarine to find five new species of black corals dwelling as deep as 2,500 feet (760 metres) below the Great Barrier Reef and Coral Sea surface off the coast of Australia.

What are Black Corals?

Colonial animals include:

  • Antipatharians, often known as black corals, are colonial creatures related to sea anemones and stony corals.
  • Their rigid, dark-coloured, black or brownish skeleton gives rise to their name.
  • There are more than 150 known species of black coral. Currently, there are at least 14 different black coral species found in Hawaii.

Distribution:

  • The deep water environments of tropical and subtropical seas are where black corals are most frequently found, while they are present in all oceans.
  • Carnivores include black corals.

Attributes:

  • Black corals can be found growing both in shallow seas and at depths of over 26,000 feet (8,000 metres), and some individual corals can survive for more than 4,000 years.
  • Several of these corals branch and appear akin to feathers, fans, or bushes, while others are straight like a whip.
  • The microscopic zooplankton plentiful in deep waters is consumed by filter-feeding black corals.
  • The light and photosynthesis provide energy for vibrant shallow-water corals.
  • Similar to shallow-water corals that create vibrant reefs teeming with fish, black corals serve as vital habitats where fish and invertebrates feed and hide from predators on a very arid sea floor.
  • Black corals are filter feeders that consume the small zooplankton plentiful in deep waters, as opposed to their colourful, shallow-water relatives that get their energy from the sun and photosynthesis.
  • In the past, corals from the region’s deep areas were gathered utilising destructive dredging and trawling techniques.
  • Five new species were discovered among the many fascinating specimens, one of which grew on a nautilus’ shell more than 2,500 feet (760 metres) below the water’s surface.
  • For instance, 2,554 distinct invertebrates lived in a single black coral colony that scientists gathered in 2005 off the Californian coast of the United States.

Black coral-related major challenges include:

  • In earlier times, dredging and trawling techniques that frequently destroyed the corals were used to obtain corals from the deep areas of this region.
  • Recent excursions were the first to deploy a robot into these deep-water environments, enabling the crew to view and securely gather deep-sea corals in their native settings.
  • Illegal harvesting of black coral for jewellery puts many of them in danger.

Describe the coral reefs –

Marine invertebrates or creatures without spines include corals. Corals are classified as belonging to the phylum Cnidaria and the class Anthozoa.

The polyps that makeup coral are genetically similar to animals. In the tissues of these polyps, there are tiny algae called zooxanthellae.

  • Algae and corals interact in a mutualistic way.
  • The chemicals required for photosynthesis are supplied to the zooxanthellae by the coral.
  • In exchange, the coral receives organic photosynthetic byproducts from the zooxanthellae, such as carbohydrates used by the coral polyps to create their calcium carbonate skeletons.
  • In addition to giving corals the nutrients they require, zooxanthellae give corals their distinctive and lovely hues.

The “rainforests of the oceans” is another name for them.

They also come in two varieties:-

Hard corals:

  • They draw calcium carbonate from the saltwater to construct the rigid, white coral exoskeletons.
  • A stiff skeleton composed of calcium carbonate (CaCO3) in the crystal form known as aragonite is produced by hard corals.
  • They are the main corals that form reefs. Hermatypic corals are hard corals that build reefs.

Soft Corals:

  • Although they are present in a reef environment, soft coral does not generate a stiff calcium carbonate skeleton and does not create reefs.
  • Most soft corals are also colonial, so what seems to be a single, enormous creature is a colony of smaller polyps joined together to form a bigger structure. Visually, soft coral colonies often resemble grasses, fans, whips, shrubs, trees, and whips.

Importance: 

  • Despite occupying just 1% of the seafloor, they support nearly 25% of marine biodiversity.
  • The marine life further fuels global fishing enterprises that coral reefs nourish.
  • Additionally, via commerce in products and services and tourism, coral reef systems create USD 2.7 trillion in economic value each year.

Source: TH