Researchers at Smithsonian Institution, Washington recently 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.

 

What are ‘corals’?

  • Corals exhibit characteristics of plants, but are marine animals that are related to jellyfish and anemones.
  • Coral polyps are tiny, soft-bodied organisms. At their base is a hard, protective limestone skeleton called a calcite, which forms the structure of coral reefs.
  • Reefs begin when a polyp attaches itself to a rock on the seafloor, then divides, or buds, into thousands of clones. The polyp calcites connect to one another, creating a colony that acts as a single organism.
  • As colonies grow over hundreds and thousands of years, they join with other colonies, and become reefs.
  • There are soft corals as well, which are non-reef-building, and resemble bushes, grasses, trees.

 

About the ‘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.
  • 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.
  • 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.
  • Similarly to shallow-water corals that build colourful reefs full of fish, black corals act as important habitats where fish and invertebrates feed and hide from predators in what is otherwise a mostly barren sea floor.
    • For example, a single black coral colony researchers collected in 2005 off the coast of California, United States, was home to 2,554 individual invertebrates.