Question

More than 93% of corals of the Great Barrier Reef in Australia were hit by coral bleaching .Consider the following statements:

Which of the above statement(s) is/are correct?

• A. Only 1
• B. Only 2
• C. Both of these
• D. None of these

Answer 1

The correct option is A Only 1

The Great Barrier Reef is the world's largest coral reef system which is also a World Heritage Site . Bleaching occurs when the conditions necessary to sustain the coral's zooxanthellae cannot be maintained. Any environmental trigger that affects the coral's ability to supply the zooxanthellae with nutrients for photosynthesis (carbon dioxide, ammonium) will lead to expulsion. This process is a "downward spiral", whereby the coral's failure to prevent the division of zooxanthellae leads to ever-greater amounts of the photosynthesis-derived carbon to be diverted into the algae rather than the coral. This makes the energy balance required for the coral to continue sustaining its algae more fragile, and hence the coral loses the ability to maintain its parasitic control on its zooxanthellae.