Dr Berkelmans fears, however, that the Great Barrier Reef is likely
to experience additional disturbances and more coral bleaching next
summer as Australia is currently in an El Niño cycle which means
unpredictable weather and often strong heat waves.
Dr Berkelmans and his team also monitored the impact of the coral
bleaching event that impacted the region earlier this year. The 2006
bleaching event was the worst bleaching event on record for the Keppel
Islands.
"While the reefs in the Keppels have amongst the highest coral
cover anywhere on the Great Barrier Reef, this year’s bleaching event
caused just under half of the region’s corals to die off. Now we are
seeing patches of reef where all the coral is dead which is quite
unusual for this area. Fortunately though, many of the seaward reefs
are still in good condition."
Dr Berkelmans’ previous research on coral bleaching has shown that
corals around the Keppel Islands are generally quite resilient to
bleaching events due to their unique ability to adapt to changing
environments.
"While Keppel corals are typically more resilient to temperature
changes than corals in other regions, no corals can tolerate prolonged
exposure to freshwater so this sort of event is both unpredictable and
unmanageable. These sorts of events demonstrate the importance of
minimising human induced stress on the reef to ensure that they are as
healthy as possible when disaster strikes."
This is not the first time reefs around the Keppel Islands have
been exposed to freshwater. A major flooding of the Fitzroy River in
1991 doused Keppel Bay and its fringing reefs in 18 million megalitres
of freshwater causing mass destruction of corals within 4m of the
surface.
"The positive side of all this is that we know that these reefs
have recovered from a similar event in the past to become some of the
most spectacular reefs on the GBR."
