100km of kelp forest died following a marine heatwave in 2011 which saw the ocean temperature increase by 2C…death of the kelp caused functional extinction of 370sq km of rocky cool-climate reefs, extending down the coast from Kalbarri, about 570km north of Perth, Western Australia.
Photograph: Darryl Torckler/Getty Images
….suggested southern kelp forests were more able to withstand heatwaves than northern kelp forests, Prof Craig Johnson, from the University of Tasmania’s Institute for Marine and Antarctic Studies, told the Guardian…He agreed with Wernberg that it was likely kelp forests would retract to the southern-most corners of the continent as temperatures warmed, which would see the majority of species dependent on the reef pushed out. Tasmania’s remaining giant kelp forests appear to have been more resilient to the heatwave…Tasmania has already lost 95% of its giant kelp forests, due to ocean warming over the past 80 years, but remaining species appear more resilient. The species grows so fast you can measure it in the morning and come out after lunch to find it’s grown another 30cm. Johnson said the value of the Great Southern Reef was “completely under-appreciated,” and that the number of endemic species was “orders of magnitude more on the Great Southern Reef than the Great Barrier Reef”…The study, Climate-driven regime shift of a temperate marine ecosystem, was published in the journal Science on Thursday