Giant rock raft not likely to ‘save’ Reef
A RAFT of volcanic pumice the size of Paris is floating faithfully towards the Australian coastline – but it may not be the coral-hitchhiking lifeline to the Great Barrier Reef it is cracked up to be.
Global media has heralded the island of floating rocks spotted near Tonga as a potential godsend for the Reef.
However, ARC Centre of Excellence for Coral Reef Studies director Terry Hughes said the possibility of corals catching a ride to replenish the gene pool was unlikely to eventuate.
“If you pick up a piece of pumice on the beach, it’s usually pretty clean,” he said.
“You can occasionally find baby corals on them, but most corals don’t settle on something that’s bobbing around on the surface of the ocean.
“They prefer something more solid and deeper.”
There are also questions over how a clingy baby coral would find its way off the buoyant rocks and onto the Reef below.
“It would have to grow big and old enough on the pumice to then reproduce a new generation of larvae that made its way onto the Reef,” Prof Hughes said.
“That would take an awfully long time.
“In theory, it could be a mechanism for delivering baby corals but it would take three to four years before they started to reproduce.
“I’m not aware of anyone showing it could happen.”
It is a spectacular sight for sailors who stumble across the phenomenon – about 150sq km of rock on the ocean’s surface, covering an area about as big as Paris.
But in the context of the 344,000sq km Great Barrier Reef, it is barely a pinprick.
“Presumably it will break up as it moves,” Prof Hughes said.
“In the meantime, there are still plenty of corals left on the Reef that survived the two bleaching events and they are reproducing.”