Are new corals in Sydney dangerous invaders or harmless refugees?
Worsening environmental pressures, such as higher sea temperatures, are causing the catastrophic loss of coral cover around the globe. As the waters of the Great Barrier Reef warm, subtropical corals are heading south in search of cooler waters.
Sydney has recently become home to a new subtropical coral, which raises a significant question: could Sydney be a refuge for corals displaced by climate change?
The answer, say coral reef researchers at the University of Technology Sydney (UTS), is yes … but.
A new study, published in Coral Reefs, analyzed the metabolism of these new corals under existing and future warming scenarios and found the invading subtropical corals will survive and thrive in coastal Sydney.
Study leader Dr. Jen Matthews, of the Future Reefs Program at UTS, says warming could spell trouble for existing 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," Dr. Matthews says.
"Coastal Sydney falls in the temperate climate zone, so the establishment of subtropical coral populations raises some interesting questions, such as how can they survive at the edge of existence? 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.
"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, co-investigator Dr. Brigitte Sommer (UTS) says there may be exciting upsides—increasing the biodiversity and complexity of Sydney's marine ecosystems could bring benefits in terms of 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," Dr. Sommer says.Ningaloo corals are ill-equipped to handle future climate change
More information: Raúl A. González-Pech et al, Physiological factors facilitating the persistence of Pocillopora aliciae and Plesiastrea versipora in temperate reefs of south-eastern Australia under ocean warming, Coral Reefs (2022). DOI: 10.1007/s00338-022-02277-0
Journal information: Coral Reefs
Provided by University of Technology, Sydney
As staghorn coral declines along Florida coast, planting project tests restoration plan
Just 150 fragments of staghorn coral planted off Florida's shore might give new hope to the state's endangered reefs.
A boat carrying those fragments set off Tuesday afternoon in Jupiter, marking the beginning of a study on the temperature tolerance of coral on Florida's northern reef tract.
"This is the farthest north that this species has been out-planted," said Shelby Thomas, the founder and CEO of the Ocean Rescue Alliance. "This will really help give us more insight in the future if it's a suitable site to expand doing coral restoration efforts in Florida, and seeing if the species can survive further north."
The Ocean Rescue Alliance is a nonprofit marine conservation and restoration organization that works in coral restoration and the creation of artificial reefs. It operates as far south as the Keys and now as far north as Jupiter.
They are working with the University of Miami to conduct research on the coral's tolerance to warmer water. The team will be monitoring the coral and collecting tissue samples on a monthly basis. They are also working with Palm Beach County and the Florida Fish and Wildlife Commission in the planting effort.
Rob Bremer, a masters student at the University of Miami, is working on this project with the Ocean Rescue Alliance. He said the deterioration of the coral off the coast of Florida makes these kinds of studies necessary.
"We lose a lot of corals every year, and the rates of reproduction are dropping as well, which is a pretty scary sign," Bremer said. "So between that and SCTLD [stony coral tissue loss disease] killing a ton of corals a year … it's not looking really good for corals both in Florida and kind of worldwide."
According to research published by the University of Florida, climate change, human stressors and stony coral tissue loss disease have greatly reduced the staghorn coral's presence in southeast Florida. A 2020 study found that staghorn coral populations have declined over 90% since the 1970s. As staghorn coral falters in its usual habitat range of the Caribbean and southeast Florida, Bremer and Thomas are testing how well it can survive at the edge of its northernmost range.
"This project has a lot of potential to prove that corals can expand outside of their natural habitats or habitat ranges," Bremer said. "If these corals survive and continue to prosper as they have, I think that assisted migration northwards...could be very much incorporated into our restoration focuses."
The Ocean Rescue Alliance also plants artificial reefs through its 1000 Mermaids Project, which aims to eventually place 1,000 artificial reefs in Florida waters in the form of mermaid sculptures. Thomas calls this project "eco art," creating habitat for marine life and a spot for fishers and divers. Currently the team's largest artificial reef consists of 35 mermaid structures off West Palm Beach.
"We can actually make a sculpture of any person or logo and make them into an artificial reef that creates fish habitat and can help create structure on the seafloor," Thomas said. "All of our sculptures still have a habitat component, so they're not just sculptures that don't add any value to the environment."
According to the National Oceanic and Atmospheric Administration, artificial reefs can have a positive ecological impact when done right. They can divert human traffic from natural reefs and provide shelter for fish and other species that need a physical habitat. However, they could potentially provide a habitat for invasive species or damage natural habitats.
"Typically, I am an advocate for artificial reefs," Bremer said. "I think that one of the biggest things they can do is raise awareness for actual reefs, and for just natural beauty. They can also pull a lot of diving pressure off of natural reefs."
This July, the Ocean Rescue Alliance plans to plant 30,000 corals near Hollywood.
"That's really going to lead way to a whole other variety of coral restoration research and community engagement," Thomas said. "So we're really looking forward to expanding our initiatives and public engagement as well."
Bremer agreed that public engagement may become increasingly important in conservation efforts.
"At the end of the day, we're probably never going to be able to do enough as scientists to completely turn the tide against global warming and other anthropogenic factors," he said. "So I think that we as a scientific community also need to become maybe more well-rounded than we're typically used to and work on engaging the public and getting our voices heard throughout policies as well."
2022 South Florida Sun Sentinel.
Distributed by Tribune Content Agency, LLC.
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