Seaweed migrates south with warming seas

By AAP and AG staff 28 October 2011
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Warming seas due to climate change have led to one-quarter of temperate seaweed species to head south.

ONE-QUARTER OF TEMPERATE seaweed species in Australia face extinction because of global warming, a new study has found.

A team of Australian scientists says temperate seaweed communities have changed over the past 50 years to the extent that they’ve become increasingly subtropical.

As a result many seaweed species have migrated towards Australia’s southern coast.

“We estimated that projected ocean warming could lead to several hundred species retracting south and beyond the edge of the Australian continent, where they will have no suitable habitat and may therefore go extinct”, the project’s lead scientist Dr Thomas Wernberg, from the University of Western Australia, said in a statement.

Historical seeweed records show species on the move

The scientists examined an extensive marine database of more than 20,000 records of seaweed collected since the 1940s.

“Importantly, we did not select species based on preconceived ideas about which ones should have shifted or not. We looked at all 1500 or so species in the southern seaweed flora and analysed all of those species that had sufficient records,” Thomas said.

He warned that marine ecosystems could suffer if the changes in seaweed had a cascading impact on other life in the sea.

“I hope people will appreciate that the threats of climate change to marine environments are not just about exotic tropical coral reefs but also are likely to affect the diversity of life across a much broader spectrum of marine ecosystems.”

The team believes its findings are important because the Southern Hemisphere has been under-represented in climate change studies.

The findings have been reported in the online journal Current Biology.