How will climate change affect Sydney’s coral reefs?

Worsening environmental pressures due to climate change, such as sea temperature rises, are causing catastrophic losses of corals all over the world. As the waters of the Great Barrier Reef (the world’s largest coral reef ecosystem) warm, subtropical corals are migrating south in search of cooler waters. Sydney’s coastline has recently become home to a new subtropical species of coral (Pocillopora aliciae), raising the question whether this place could become a refuge for corals displaced by climate change.

A new study led by the University of Technology Sydney (UTS) has analyzed the metabolism of these new corals under current and future warming scenarios, and found that these invading subtropical corals will survive and thrive in their new habitat. However, the experts argue that warming could pose significant problems for the native Sydney coral species. 

“While we found these corals possess the machinery to withstand large changes in temperature, those temperatures could kill the existing corals in Sydney. This is incredibly important when we consider the future of Sydney’s precious ecosystems,” said study senior author Jennifer Matthews, a coral biologist at UTS.

“The ecological services and economic revenue of the Sydney marine environment make it a very valuable ecosystem, but it is under continuous threat from climate change and urbanization, causing increased stormwater inflows and habitat modification.”

However, according to study co-author Brigitte Sommer (a marine ecologist at UTS), increasing the biodiversity and complexity of Sydney’s marine ecosystems could bring significant benefits, by turning this region into a refuge for reef fish, coral crabs, and potentially other coral species.

“Determining which coral species will be able to migrate poleward in warming seas and how they will interact with local species is critical so we can protect these dynamic ecosystems into the future,” she explained.

“We are continuing to examine how corals can live and breed in temperate, or suboptimal, environments, and how we might use this knowledge to help us to protect Australia’s reefs into the future,” concluded Dr. Matthews.

The study is published in the journal Coral Reef.

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By Andrei Ionescu, Earth.com Staff Writer