Michael and Larissa Hoult were sailing from the Vava’u islands off Tonga to Fiji when they saw it – a “total rock rubble slick” extending for kilometres around them.
The rocks, some the size of marbles and others as big as basketballs, bumped against their boat and clogged their rudders.
What the couple was seeing was a giant “pumice raft”, a mass of floating, porous rock that forms when a volcano erupts from the ocean floor.
The raft has been compared in size to Manhattan, Washington and 20,000 football ovals.
Scott Bryan, a geologist and associate professor at Queensland University of Technology says,
“This mass is slowly floating toward Australia’s coastline – where in seven to 12 months it could arrive with a host of marine life ready to potentially revive the badly damaged Great Barrier Reef.”
Bryan says, “In this 150-odd square kilometre of pumice out there right now, there’s probably billions to trillions of pieces of pumice all floating together, and each piece of pumice is a vehicle for some marine organism.”
However, it’s possible the raft might not even make it to Australia, as over time it’s likely to break up, which would be a real shame given that if the planet continues to warm, the world’s coral reefs won’t be saved by a pumice raft or any other technological tools.