A 'Raft' of Volcanic Stone May Be a Lifesaver for the Great Barrier Reef

The pumice 'raft' as seen by NASA's Earth Observatory. NASA Earth Observatory

It’s hard to think about the Great Barrier Reef without getting a certain sinking feeling. Recent years have not been kind to the world’s most spectacular and vital reef system.

It has suffered unprecedented coral bleaching events, cyclones, heating waters, acidification and countless other calamities climate change has thrown its way. As a result, more than half of its corals have died in recent years.

But hope, for the Great Barrier Reef, may actually float. In fact, an unlikely delegation is on its way to give it a hand, dispatched from an even unlikelier source — a volcano.

A “raft,” spotted by the NASA Earth Observatory earlier this month, was likely spit out by an undersea volcano near the island of Tonga. It’s roughly the size of Manhattan. But most importantly, it’s teeming with life. And, if it continues on its course toward northeastern Australia, those organisms reinvigorate the reef’s ailing corals.

And how, you might ask, does stone sail the high seas? It helps if you think of pumice as a kind of mineralogical Swiss cheese.

“One of the more subtle and rarely observed displays is the pumice raft," NASA notes in a release. “Many of the world's volcanoes are shrouded by the waters of the oceans. When they erupt, they can discolor the ocean surface with gases and debris. They also can spew masses of lava that are lighter than water. Such pumice rocks are full of holes and cavities, and they easily float."

Those nooks and crannies also happen to make ideal homes for marine creatures.

“Pumice rafts can drift for weeks to years, slowly dispersing into the ocean currents,” volcanologist Erik Klemetti of Denison University explains in the NASA release. “These chunks of pumice end up making excellent, drifting homes for sea organisms, helping them spread.”

And if that pumice raft should alight in the vicinity of the Great Barrier Reef, those organisms could disembark and even colonize the coral system.

'It was quite eerie, actually'

While NASA first detected the underwater outburst, Australian sailors actually had the surreal experience of traveling through it. In an interview with CNN, they described sailing through an endless stretch of volcanic rocks "made up of pumice stones from marble to basketball size such that water was not visible."

"It was quite eerie, actually," Larissa Hoult noted “The whole ocean was matte — we couldn't see the water reflection of the moon."

You can get a sense of that experience in the video below:

"The rocks were kind of closing in around us, so we couldn't see our trail or our wake at all. We could just see the edge where it went back to regular water — shiny water — at night," Michael Hoult added.

And it’s likely they only beheld a fraction of the formation, with most of its heft concealed beneath the surface.

That, too, is where countless passengers are likely housed, and — if ocean currents and winds are just right — could eventually disembark in a certain port in northeastern Australia.

That could take between seven and 12 months, Scott Bryan, a professor at Queensland University of Technology, tells the Australian Broadcasting Corporation. By then, he suggests, it will be “covered in a whole range of organisms of algae and barnacles and corals and crabs and snails and worms.”

Godspeed, pumice stone.