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.