New corals spawn on Australia's Great Barrier Reef; what's the significance of this annual event

In a positive sign showing regeneration of the endangered Great Barrier Reef in Australia, the coral spawning event was witnessed last week off the coast of Cairns, Queensland.

The scientists working beneath the waves were able to capture on video the event when corals released billions of sperm and eggs, creating a riot of colours in the World Heritage-listed natural wonder.

Coral spawning is the sexual reproduction of corals. For most of their life, corals actually grow by asexual reproduction -- they split into two, four, and so on -- but once a year (usually between October and December), a few nights after the full moon, they actually create bundles of sperm and egg and release them into the water.

Subsequently, these sperm and egg bundles meet other bundles from the same species for fertilisation. Later, the fertilised eggs develop into coral larvae and settle on the sea bed. This spawning event takes place across the entire length (2,600 km) of the Great Barrier Reef.

Thrilled with the event, the Great Barrier Reef Marine Park Authority tweeted, "Coral spawning is genetic gold for #Reef resilience! The transfer of their resilient genes to the next generation of corals will be pivotal for the long-term health of the #GreatBarrierReef.

Coral reefs are extremely sensitive to changes in water caused by the absorption of carbon dioxide. Therefore, global warming and climate change are leading to coral bleaching -- a process when corals lose the algae that give them their vibrant colours.

According to World Wide Fund for Nature, "Coral bleaching matters because once these corals die, reefs barely come back. With few corals surviving, they struggle to reproduce, and entire reef ecosystems, on which people and wildlife depend, deteriorate."

In the wake of this degradation, marine biologists have said that the recent coral spawning event was 'encouraging'.Earlier this month, a study by James Cook University in Australia had revealed that only 2 percent of the reef has escaped bleaching since 1998. The bleaching was caused due to climate change. The study added that the Great Barrier Reef would only survive if global warming is kept under 1.5 degrees.