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To commemorate Earth Day 2021, AZoCleantech looks at coral reef damage and if restoration projects are enough to save our underwater ecosystems. Earth’s coral reefs are in danger, with climate change and environmental damage already responsible for the ongoing destruction of the world’s reefs. Restoration attempts are underway, but are they enough to halt the death of these important living ecosystems?
Coral reefs rank amongst the most diverse ecosystems on the face of planet Earth, playing host to thousands of different species of animals.
These reefs are now dying at an alarming rate as they have been exposed to a wide range of stressors, such as rising ocean temperatures, increasing pollution, and over-fishing. These factors are causing bleaching events that result in mass coral deaths.
With Earth Day 2021 (April 22) rapidly approaching with its theme of restoring the Earth, now is the ideal time to consider coral recovery and if we are doing enough to combat it.
The Effects of Coral Bleaching and How it can be Tackled
Bleaching damages coral by forcing it to eject algae that live within its tissues, turning them pale and even white in the process.
Bleaching does not outright kill corals, so they are able to recover from such events. However, it takes around 10 years for corals to bounce back. As incidents become more frequent, they are currently happening around once every six years, the time to recover between subsequent large-scale occurrences reduces and leaves insufficient recovery times.
This has resulted in a situation in which 50% of the world’s corals have died in the last 30 years, and researchers predict that 90% of coral reefs will be gone by the 2100s. Of course, there are recovery operations that are underway that aim to improve the health of coral reefs.
Welcome to the Biggest Reef Restoration Effort on the Planet
Video Credit: Coral Restoration Foundation/YouTube.com
In 2021, The Marine Conservation Society Seychelles (MCSS) began a large-scale coral reef restoration project in the Saint-Anne Marine National Park. The project will attempt to reverse some of the damage caused by bleaching events by rehabilitating the reef in the marine park.
The method employed by the team involves collecting fragments of coral reefs that have survived bleaching events and translating them into a coral nursery where the coral is carefully monitored for one year.
This process of coral gardening is also being employed in Australia in an attempt to help maintain the health of the country’s Great Barrier Reef, the world’s largest coral reef which stretches for 2300 kilometers and is home to 2,900 individual reefs and 900 islands.
In addition to coral gardening, the Australian government is also testing the use of physical sunscreens and underwater fans which cool small regions of the coral reef.
But are these efforts enough?
Researchers Say Current Measures Are Not Enough to Save Reefs
Terry Hughes, a prominent coral reef researcher believes that current measures are insufficient.
As Australia’s leading expert on such reefs, Hughes, former Director of the ARC Centre of Excellence for Coral Reef Studies (2005–2020), believes that efforts underway in Australia to save the Great Barrier Reef, simply will not save the World’s largest coral reef system.
He also believes they may ultimately do more harm than good.
While Hurst considers the projects suggested by the Australian government to be feasible, he believes they will act as a distraction from the real work needed to save the reef. Hughes points towards the need to address the root cause of harm to coral reefs — namely climate change.
Ove Hoegh-Guldberg, a biologist and climate scientist specializing in coral reefs recently said that if the climate goal set by the Paris Agreement of 1.5 degrees warming was met, the Great Barrier reef would still shrink by at least 70%. In a recent report entitled ‘The Risks to Australia of a 3C Warmer World’ the Australian Academy of Science acknowledges that this target is now ‘virtually impossible.’
This presents the stark reality of a potential 2-degree rise which would strip the reef back to just 1% of its current size. The report lays out a striking picture of the consequences of a 3-degree rise, including the destruction of some of the country’s most delicate ecosystems — including the Great Barrier Reef.
The report explains, “Critical thresholds in many natural systems are likely to be exceeded as global warming of 1.5°C above pre-industrial levels continues. These impacts will increase as global warming reaches 2°C and beyond, with iconic ecosystems such as the Great Barrier Reef and the World Heritage-listed Kakadu National Park being severely affected.”
“At 3°C of global warming, many of Australia’s ecological systems would be unrecognizable. The decline of Australia’s natural resources would accelerate through changing distributions or loss of thousands of species and disrupted ecological processes such as habitat maintenance.”
Australia is not the only country in which scientists are expressing concern regarding current reef recovery measures.
A Glimmer of Hope for Coral Reefs
A 2018 report from the National Academies of Sciences in the US indicated that while the management of regional stressors that threaten coral reefs is vital, in isolation, they will not be enough in the face of global climate change to save reefs.
However, the report, authored by Robert Richmond, research professor and director at Kewalo Marine Laboratory in the School of Ocean and Earth Science and Technology (SOEST), the University of Hawaiʻi, Mānoa, indicated that the complex nature of corals lends itself to a wide range of possible approaches — both long and short-term.
The researcher believes that a growing body of research on coral physiology, ecology, molecular biology, and responses to stress has revealed potential tools to increase coral resilience.
Other research suggests that corals may be more resilient to bleaching than previously believed.
At the end of 2020, a study from biologists from the University of Victoria (UVic) showed that some corals have displayed unexpected resistance to rising ocean temperatures driven by unprecedented heatwaves. The discovery has positive implications for the long-term survival of coral reefs in the face of global warming.
While positive, the team pointed out that this increased temperature resistance was only present under the correct conditions and when corals were not exposed to additional stressors such as pollution.
The team’s research clearly shows that there is no magic solution to coral recovery that does not include humanity changing its patterns of behavior, something that all researchers can agree on.
One thing is also abundantly clear, the loss of corals would not just have a devasting impact on the communities that have grown to depend on them, it would cause the extinction of a wide range of animal life, making the oceans less wonderous and beautiful.
References and Further Reading
‘Climate change and coral bleaching,’ Arc Centre of Excellence, [https://www.coralcoe.org.au/for-managers/coral-bleaching-and-the-great-barrier-reef]
‘Restoring Marine Ecosystem by restoring coral reefs to meet a changing climate future,’ The Marine Conservation Society Seychelles (MCSS), [https://www.mcsscoralrestoration.com/]
‘The risks to Australia of a 3°C warmer world,’ Australian Academy of Science, [https://www.science.org.au/supporting-science/science-policy-and-analysis/reports-and-publications/risks-australia-three-degrees-c-warmer-world]
Claar. D.C., Starko., Baum. J.K., et al, , ‘Dynamic symbioses reveal pathways to coral survival through prolonged heatwaves,’ Nature Communications, [https://doi.org/10.1038/s41467-020-19169-y]