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Seaweed-Free Beaches Predicted as Oceans Warm

Rapid warming of Western Australia’s coastal waters could see its beaches free of stinking piles of seaweed in what could become a test case for more slowly warming waters elsewhere.

New research from Edith Cowan University’s Centre of Marine Ecosystems investigated the potential shift of species of marine life as ocean temperatures warm with climate change. Lead researcher A/Prof Glenn Hyndes said one of the potential impacts of the process, known as tropicalisation, is the movement of herbivorous fish species south from sub-tropical waters.

“What’s likely to happen as these species move south with warming waters is that they could start foraging on the different species of seagrass found around the south-west of Western Australia,” he said. “This increased foraging could decimate those local species, meaning there’s nothing washing up on our beaches.

“That might sound like it’s good news,especially if you live near one of those beaches where seagrass wash up regularly – also known as ‘wrack’. But it would have disastrous consequences for the coastal ecosystems in those areas which rely on the nutrients and habitat provided by the wrack to survive.”

Hyndes and colleagues used information on projected sea temperature rises to predict the distribution of species of seagrass, fish, turtles and dugong in 2100. “We predict that that change in sea temperature will see some species move more than 500 km south along the WA coast,” he said.

Hyndes said the changes predicted in Western Australia are happening more rapidly than elsewhere in the world. “The speed at which we’re predicting changes will happen along the Western Australian coast means that what goes on here could provide valuable lessons for similar ecosystems around the world,” he said.

“Seagrass meadows are incredibly important habitats for a huge number of species as well as for their ability to absorb atmospheric carbon dioxide at a rate 40 times higher than tropical rainforests.”

The research was published in Biosciences (http://tinyurl.com/jclwf9f).