Hardy – vigorous corals (Blue Rice Corals)

Hardy – vigorous corals (Blue Rice Corals)

Subject : Environment

Context : In 2014 and 2015, the brown rice coral in Hawaii was completely bleached, but the blue rice coral recovered quickly after bleaching, and blue coral was unaffected by the elevated ocean temperatures.

Concept :

• Hawaiian blue rice corals have a deep blue pigment derived from algae called zooxanthellae that live inside the coral tissue.
• The researchers found that these algae produce sunscreen for the coral.
• This pigment has a protein named chromoprotein which filters out harmful UV radiation.
• After the 2014 and 2015 Hawaii bleaching events, the blue rice coral was found to have exceptional reproductive vigour at 90% motility.
• But the brown coral’s motility was only half this. A key factor in the blue rice coral’s ability to reproduce successfully might be its sunscreen pigment, which the coral may retain even if it bleaches.

Corals:

• Corals are 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 the 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”.

There are two types of corals:

• Hard, shallow-water corals—the kind that builds reefs.
• Soft corals and deep water corals that live in dark cold waters.