RACHEL MARTIN, HOST:
Now to what is being called a raft of rocks floating in the Pacific Ocean. It's about 60 square miles of pumice - this is a lightweight volcanic rock that forms when lava is rapidly cooled - that is roughly the size of Manhattan. And experts believe it's likely the product of an underwater volcano near Tonga.
DAVID GREENE, HOST:
Scientists actually think this big raft of rock may have picked up some travelers along the way. They say it's likely marine life has hitched a ride on the floating pumice, which could be good news if it reaches Australia. This is geologist Scott Bryan with the Queensland University of Technology.
SCOTT BRYAN: I think this is a great opportunity for these pumices to pick up corals and other reef-dwelling organisms and reef-building organisms and transport them in really large numbers to the Great Barrier Reef.
MARTIN: Australia's Great Barrier Reef is an ecosystem that has been hit hard by climate change.
BRYAN: We've had some fairly significant coral bleaching events. But probably cyclones have been quite devastating to particular areas of the Great Barrier Reef.
MARTIN: But if this raft of rocks - some the size of marbles, others the size of basketballs - if this is teeming with sea life and if it reaches Australia's coast in several months, it could bring an injection of life for Australia's most cherished natural wonder.
BRYAN: So this is a mechanism that's sort of helping that opportunity for the reef to rebuild and restock.
GREENE: But scientists are urging caution and saying not to get too excited. Researcher Terry Hughes, the director of the ARC Centre of Excellence for Coral Reef Studies, went on Twitter and noted that saving coral reefs depends on action on climate change and that there is no, quote, "silver bullet."
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