(CNN) A "raft" of floating pumice rock the size of Manhattan is drifting towards Australia, bringing along with it new marine life that could help with the recovery of the Great Barrier Reef's corals, half of which have been killed in recent years as a result of climate change.

Experts say that if the pumice makes it to the Great Barrier Reef, it could help replenish some of the lost marine life. The raft is believed to be home to organisms like crabs and corals.

The massive floating sheet of volcanic rock was first spotted by sailors on August 9, days after an underwater volcano is believed to have erupted near the Pacific Island of Tonga, according to NASA Earth Observatory

Days later, Australian sailors heading towards Vanuatu on the ROAM catamaran said they encountered volcanic rocks "made up of pumice stones from marble to basketball size such that water was not visible."

ROAM crew Michael and Larissa Hoult told CNN that they had been at sea for 10 days before coming into contact with the gray floating matter one evening.

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