CORALS

CORALS

Subject: Environment

Context: New findings from Rutgers University say corals will survive climate change. This is owing to their capacity to form rock hard skeletons, the study finds.

Concept:

• Coral 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 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 2 types of corals:

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

Coral Bleaching

• When corals face stress by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae zooxanthellae living in their tissues, causing them to turn completely white. This phenomenon is called coral bleaching.
• The pale white colour is of the translucent tissues of calcium carbonate which are visible due to the loss of pigment producing zooxanthellae.
• Corals can recover if the stress-caused bleaching is not severe.
• Coral bleaching has occurred in the Caribbean, Indian, and Pacific oceans on a regular basis.