Record coral kill-off on Great Barrier Reef
SCIENTISTS yesterday confirmed a mass bleaching event on the Great Barrier Reef this year killed more corals than ever before, with more than two thirds destroyed across large swathes of the biodiverse site.
The 2300-kilometre long (1400mile) reef – the world’s biggest coral ecosystem – suffered its most severe bleaching in recorded history due to warming sea temperatures during March and April with the northern third bearing the brunt.
Follow-up underwater surveys, backing earlier aerial studies, have revealed a 700-kilometre stretch of reefs in the less-accessible north lost 67 percent of their shallow-water corals in the past eight to nine months.
But further south over the vast central and southern regions, including tourist areas around Cairns, there was a much lower death toll.
“Most of the losses have occurred in the northern, most-pristine part of the Great Barrier Reef,” said Terry Hughes of James Cook University.
“This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected.”
Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their colour.
Scientists estimate the northern region, which teems with marine life, will take at least 10-15 years to regain lost corals, but are concerned that a fourth major bleaching event may occur before that. –