Great Barrier Reef bursts into life during a ‘magical’ coral spawning event

The Great Barrier Reef has undergone its annual coral spawning, filling the Australian landmark with a stunning array of colors.

Scientists diving beneath the waves reported witnessing the event, where coral release sperm and eggs in unison, off the coast of Cairns, Queensland, on Tuesday night. They hailed it as a positive sign of the reef’s ability to regenerate despite environmental challenges.

“Nothing brings more joy than witnessing new life – and coral spawning is the ultimate testament to that,” said Australian marine biologist Gareth Phillips, who had a front-row view of this year’s coral spawn, in a statement from Queensland Tourism and Events.

Phillips, from the research center Reef Teach, along with his team of marine biologists, divers, students, and photographers, dived to the ocean floor to capture footage of the coral near Cairns, Queensland. Over the coming days, they will visit other reef sites to film and observe.

This footage will enable scientists to track this year’s coral growth and monitor the overall health of the Great Barrier Reef, which is protected by UNESCO and, this year, successfully avoided an ‘in danger’ status from the World Heritage Committee.

‘Magical’ conditions

Phillips described the task of monitoring this year’s coral spawn off Cairns as ‘the ultimate treasure hunt.’

“I’ve witnessed corals erupting all at once, but this time it felt different. Various species seemed to spawn in waves, one after another. The conditions were magical – the water was like glass, with beautiful moonlight illuminating everything,” he said.

Philips mentioned that his team swam around searching for coral ready to spawn.

“Once we spotted a coral ready to spawn, we observed it taking about 30 seconds for each colony to complete the process. It felt like the ultimate treasure hunt … so thrilling that we even called the skipper in and got him into the water,” he added.

The Great Barrier Reef’s coral spawning is a synchronized annual event. For most of the year, coral reproduces by splitting and dividing, but once a year, the coral releases sperm and eggs in unison into the ocean.

“Each coral larvae drifts along the currents until it eventually settles on the sea floor,” explained Philips. “Spawning occurs over several nights, with different species releasing their gametes on different evenings.”

The Great Barrier Reef Foundation explains that in order for coral to reproduce, bundles of sperm and eggs need to find one another from the same species. By releasing their bundles at the same time, corals improve the chances of successful fertilization.

The annual coral spawn typically happens between October and November, but the timing can be influenced by factors such as water temperature and ocean currents. The spawn date can also vary across the entire 2,300-kilometer (1,429-mile) stretch of the Great Barrier Reef.

A beacon of hope

For Philips, the coral spawning represents a glimmer of hope amid the environmental challenges that recently led UNESCO to request a report on the Great Barrier Reef’s conservation status from Australia by February 2022.

Earlier this month, a study from James Cook University revealed that only 2% of the reef has escaped the impacts of bleaching, a result of heatwaves, since 1998.

Philips expressed it was ‘gratifying’ to witness the reef’s rejuvenation, coinciding with Australia’s decision to ease some of the world’s strictest Covid travel restrictions.

‘It’s a powerful indication that the reef’s ecological systems are functioning well, even after undergoing a recovery phase lasting over 18 months,’ he remarked.

‘The reef, much like ourselves, has faced challenges, but it’s still showing resilience – and that’s something to be hopeful about. We must celebrate the triumphs as we move forward from the pandemic,’ he added.