BLACK CORALS - ENVIRONMENT

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

 

What's in the news?

       Using a remote-controlled submarine, researchers at Smithsonian Institution, Washington, discovered five new species of black corals living as deep as 2,500 feet (760metres) below the surface in the Great Barrier Reef and Coral Sea off the coast of Australia.

 

Black corals:

       Black Corals are known as deep-sea corals are found in all oceans but are most common in deep water habitats of tropical and subtropical seas.

 

Habitat:

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

       They are located in deep oceans so they do not require light for their growth.

 

Features:

       Unlike reef-building corals in the shallower waters above, black corals lack symbiotic algae (zooxanthellae) in their tissues. Unlike colorful, shallow-water corals that rely on the sun and photosynthesis for energy, black corals are filter feeders and eat tiny zooplankton that are abundant in deep waters.

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

       Black corals are rarely black, but rather vary in color from white to red, green, yellow, or brown.

       A black coral reproduces both sexually and asexually throughout its lifetime.

 

Significance:

       Black corals act as an important habitat where fish and invertebrates feed and hide from predators in what is otherwise a mostly barren sea floor.

 

Concerns:

       Black corals have been declining in numbers and are expected to continue declining due to the effects of poaching, ocean acidification and climate change.

 

Key takeaways:

       Among the many interesting specimens studied, there were five new species – including one that was found growing on the shell of a nautilus more than 2,500 feet (760metres) 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.