Five new species of black coral discovered living thousands of feet below the ocean’s surface near the Great Barrier Reef

Scientists have discovered five new species of black coral living thousands of feet below the ocean surface near the Great Barrier Reef.Black corals (Anthozoa: Antipatharia) 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.

However, the taxonomy of black corals is poorly known compared to many other anthozoan groupsMany 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.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.

Coral Reefs

• Corals are marine invertebrates or animals which do not possess a spine. In scientific classification, corals fall under the phylum Cnidaria and the class Anthozoa.
• Coral is made up of genetically identical organisms called polyps. These polyps have microscopic algae called zooxanthellae living within their tissues.
• The corals and algae have a mutualistic relationship.
• The coral provides the zooxanthellae with the compounds necessary for photosynthesis.
• In return, the zooxanthellae supply the coral with organic products of photosynthesis, like carbohydrates, which are utilized by the coral polyps for synthesis of their calcium carbonate skeletons.
• In addition to providing corals with essential nutrients, zooxanthellae are responsible for the unique and beautiful colors of corals.
• They are also called the “rainforests of the seas”.

Further, they are of two types

Hard corals

• They extract calcium carbonate from seawater to build hard, white coral exoskeletons.
• Hard corals produce a rigid skeleton made of calcium carbonate (CaCO3) in a crystal form called aragonite.
• They are the primary reef-building corals. Hard corals that form reefs are called hermatypic corals.

Soft Corals

• Soft coral does not produce a rigid calcium carbonate skeleton and do not form reefs, though they are present in a reef ecosystem.
• Soft corals are also mostly colonial; what appears to be a single large organism is actually a colony of individual polyps combined to form a larger structure. Visually, soft coral colonies tend to resemble trees, bushes, fans, whips, and grasses.

Significance

• They support over 25% of marine biodiversity even though they take up only 1% of the seafloor.
• The marine life supported by reefs further fuels global fishing industries.
• Besides, coral reef systems generate USD 2.7 trillion in annual economic value through goods and service trade and tourism.