Great Barrier Reef in Australia for the first time has suffered?

a. Coral bleaching two years in a row

b. Coral bleaching three years in a row

c. Coral bleaching four times in a row

d. Coral bleaching five times in a row

ANSWER: Coral bleaching two years in a row

Explanation:

Great Barrier Reef in Australia's eastern coast has experienced an unprecedented second straight year of massive coral bleaching.

This marks the first time Great Barrier Reef has bleached two years in a row.

In March and April 2016, the 2,300 km reef had its most severe bleaching on record due to rising sea temperatures.

Coral Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their colour.

The 2016 bleaching was more severe in the northern areas of the bio-diverse site.

But now more bleaching was being observed in the central part of the reef, which earlier had escaped widespread severe bleaching.

The back-to-back occurrence of widespread bleaching is resulting in decrease in stress tolerance of these corals, which means that they may not fully recover.

Know More: Great Barrier Reef

It is the biggest coral reef system in the world composed of over 2,900 individual reefs and 600 types of hard and soft corals.

It was recorded as a World Heritage site in 1981.

The reef is located in the Coral Sea, north east of Australia and covers an area of around 348,000 sq km.

It is the world’s biggest single structure made by living organisms and is seen from the outer space.

Area: 344,400 km²

UNESCO World Heritage Site inscription: 1981