Healthy coral reefs are essential for the survival of thriving ocean ecosystems and act as a natural barrier against severe weather events. Unfortunately, coral reefs and the unique ecosystems they create are currently under severe threat due to climate change. In response to this issue, the ReCoral by ØrstedTM project was launched in 2022 to investigate the potential of offshore wind turbine foundations as an additional habitat for coral growth.
The ReCoral project is a proof-of-concept trial conducted in partnership with the Penghu Marine Biology Research Centre. This initiative aims to support the natural coral growth on the foundations of offshore wind turbines located on the Greater Changhua offshore wind farms in Taiwan. It could provide a new approach to scaling up coral restoration methods on other offshore wind farms worldwide [1].
Figure 1: ReCoral Illustration by Gabby Rush.
Exploring the Depths: The Significance of Coral Reefs Up Close
Coral reefs are home to a diverse range of species. A single reef can provide shelter to thousands of species. For example, the Great Barrier Reef, located off the coast of Australia, is home to over 400 types of coral, 1,500 fish species, and 4,000 mollusc species, as well as six of the world’s seven sea turtle species. The Coral Triangle, a marine region in Southeast Asia stretching across Indonesia, Malaysia, the Philippines, and Papua New Guinea, boasts the highest level of biodiversity of any marine ecosystem on Earth.
The value of coral reefs is estimated to be around £6 trillion annually. This is due, in part, to the critical role they play in supporting the fishing and tourism industries, as well as their contribution to coastal protection. More than 500 million people worldwide rely on coral reefs for employment opportunities, food, and protection from coastal threats.
The ridges in coral reefs act as barriers that can reduce wave energy by up to 97%, providing crucial protection against natural disasters like tsunamis. Additionally, coral reefs safeguard other ecosystems, such as mangrove forests and seagrass beds, which serve as nurseries for marine animals and benefit human coastal populations.
Researchers have discovered that extracts from animals and plants living on coral reefs can be used to develop treatments for various medical conditions such as asthma, arthritis, cancer, and heart disease [2].
From Seaweed to Success: Coral Aquaculture Then and Now
Coral aquaculture, also known as coral farming or coral gardening, involves cultivating coral for commercial purposes or restoring reefs, like the ReCoral project. This practice has been in place for many decades, with one of the earliest attempts made at Nouméa Aquarium in 1956. During that time, it was common for aquarium hobbyists in Germany to create home “mini reefs.” Commercial coral propagation began in America in the 1960s, and the hobby industry took off in the early 1980s, primarily due to hobby magazines. In 2009, the US government granted $3.3 million for a project to cultivate 5,000 colonies of Acropora, a genus of small polyp hard coral. Researchers claimed that transplanting 35 colonies annually would restore coral populations to 1970s levels within ten years.
The ReCoral project employs a less invasive approach to coral restoration. It involves collecting coral spawn that naturally washes up on the shoreline of the Penghu Islands. After collection, the coral spawn is taken to the laboratory, where it is carefully cultivated before being introduced into mesh cages designed to fit around the turbine foundation pieces. The idea is that these mesh cages will provide a suitable environment for the coral larvae to settle and grow successfully.
Due to severe weather conditions such as cyclones and temperature changes affecting most coral reefs in the sea, coral bleaching has become a major concern. The turbine foundations provide a suitable environment for corals to thrive. Corals live in symbiosis with an alga called zooxanthellae that relies on sunlight for photosynthesis, meaning they must live near the surface. On the turbine foundation, by contrast, the corals will have good access to light while protected from extreme temperatures by the natural circulation of the cooler, deeper water the turbines stand in [3].
However, the ReCoral method needs further testing and refinement, and its impact needs to be measured and reported before ØrstedTM can scale it up and use it in other locations with similar habitat conditions [1].
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References
[1] https://orsted.com/en/who-we-are/sustainability/nature/net-positive-biodiversity-impact/recoral
[3] https://en.wikipedia.org/wiki/Aquaculture_of_coral
