Reef boom beats doom
Marine scientists say they are astonished at the spectacular recovery of certain coral reefs in Australia's Great Barrier Reef Marine Park from a devastating coral bleaching event in 2006.
That year high sea temperatures caused massive and severe coral bleaching in the Keppel Islands, in the southern part of the GBR. The damaged reefs were quickly smothered by a single species of seaweed — an event that can spell the total loss of the corals.
However, a lucky combination of rare circumstances meant the reefs were able to achieve a spectacular recovery, with abundant corals re-established in a single year, says Dr Guillermo Diaz-Pulido, from the ARC Centre of Excellence for Coral Reef Studies (CoECRS) and the Centre for Marine Studies at The University of Queensland.
Dr Diaz-Pulido explains that the rapid recovery is due to an exceptional combination of previously-underestimated ecological mechanisms.
"Three factors were critical. The first was exceptionally high re-growth of fragments of surviving coral tissue. The second was an unusual seasonal dieback in the seaweeds, and the third was the presence of a highly competitive coral species, which was able to outgrow the seaweed.
"But this also all happened in the context of a well-protected marine area and moderately good water quality", said Dr Diaz-Pulido.
"It is rare to see reports of reefs that bounce back from mass coral bleaching or other human impacts in less than a decade or two," he adds