Offshore wind farms often come under fire for the damage they wreak on marine habitats, but scientists say they could help ecosystems by growing coral.
Experts at Danish sustainable energy company Ørsted plan to create coral colonies on the steel foundations of four offshore wind turbines off the coast of Taiwan.
Together with Taiwanese partners, the company will test the concept, dubbed ‘ReCoral’, in the tropical waters near Taiwan’s Penghu Islands starting next month.
Relatively stable water temperatures at offshore wind farm locations will limit the risk of ‘coral bleaching’ and allow healthy corals to grow, the experts say.
Coral bleaching is when corals become white due to various stressors, such as changes in temperature, and is therefore caused by climate change.
Ørsted, the world’s most sustainable energy company, is planning a world-first attempt to support coral reefs by growing corals on offshore wind turbine foundations. Here is an artist’s impression of how the coral will look on the steel foundations
The coral will be grown on the recently-built Greater Changhua Offshore Wind Farms off the coast of Taiwan
HOW DOES THE RECORAL PROJECT WORK?
Every year, coral spawn spreads throughout the marine environment and washes up on the shore.
Researchers have already collected coral spawn that has washed up along the shoreline of Taiwan’s Penghu Islands.
When it was brought to Penghu Marine Biology Research Center labs, the coral spawn was prepared to undergo metamorphosis and develop into larvae.
Over a seven-day incubation phase, the larvae have been monitored, nourished and prepared to settle into a new environment.
In 2021, researchers successfully grew juvenile corals on underwater steel and concrete substances at a quayside test facility.
The next step, due to happen in June 2022, is applying this technique to the wind turbines in an attempt to settle the larvae and grow corals.
The coral will be grown on the recently-built Greater Changhua Offshore Wind Farms, about 30 miles north of Taiwan’s Penghu Islands.
‘Ørsted is planning a world-first attempt to support coral reefs by growing corals on offshore wind turbine foundations,’ the firm said in a statement.
‘The aims are to determine whether corals can be successfully grown on offshore wind turbine foundations and to evaluate the potential positive biodiversity impact of scaling up the initiative.’
Although wind turbines produce a form of environmentally-friendly renewable energy, their installation has been criticised for habitat destruction.
For example, many are built on sandbanks, where sea birds feed on fish. Migrating birds are also at high risk of colliding with the giant blades while in flight.
Despite this, Ørsted says wind turbines are crucial in the switch away from harmful non-renewable fossil fuels such as coal and gas.
These non-renewable sources release harmful greenhouse gases, which increase Earth’s temperatures and threaten terrestrial and marine species, including coral.
As ocean temperatures rise, warmer waters stress corals, causing them to release algae that live inside them, which gives them up to 90 per cent of their energy.
This event causes the vibrantly-coloured communities of coral to turn white – an effect called coral bleaching.
The Greater Changhua Offshore Wind Farms are about 30 miles north of Taiwan’s Penghu Islands
Coral bleaching is when corals become white due to various stressors, such as changes in temperature, and is therefore caused by climate change. Pictured, dead table coral bleaching in Wakatobi National Park, Indonesia
WARM OCEANS CAUSE CORAL BLEACHING
Corals have a symbiotic relationship with a tiny marine algae called ‘zooxanthellae’ that live inside and nourish them.
When sea surface temperatures rise, corals expel the colourful algae. The loss of the algae causes them to bleach and turn white.
This bleached states can last for up to six weeks, and while corals can recover if the temperature drops and the algae return, severely bleached corals die, and become covered by algae.
In either case, this makes it hard to distinguish between healthy corals and dead corals from satellite images.
This bleaching recently killed up to 80 per cent of corals in some areas of the Great Barrier Reef.
Bleaching events of this nature are happening worldwide four times more frequently than they used to.
The ARC Centre of Excellence in Australia previously estimated that only the southern third of the Great Barrier Reef has escaped unscathed from coral bleaching.
Bleached corals are not dead, but are at a higher risk of dying, and these bleaching events become more common under climate change.
According to Ørsted, coral bleaching affects coral at shallow waters where there are increased surface temperatures.
Conversely, at offshore wind farm locations further offshore, temperatures are more stable due to ‘vertical mixing’ in the water column, preventing extreme temperature increases.
Vertical mixing is the upward and downward movement of air or water that occurs as a result of temperature differences between layers of the fluid.
The genesis of the ReCoral project is a natural event that happens every year: coral spawn spreads throughout the waters and washes up on the shore.
Researchers have already collected coral spawn that has washed up along the shoreline of the Penghu Islands, where the labs of Penghu Marine Biology Research Center are based.
When collected and taken to the labs, the coral spawn was prepared to undergo metamorphosis and develop into larvae.
Over a seven-day incubation phase, the larvae are monitored, nourished and prepared to settle into a new environment.
Last year, researchers successfully grew juvenile corals on underwater steel and concrete substances at a quayside test facility.
The next step is applying this technique to the wind turbines in an attempt to settle the larvae and grow corals.
Rather than removing anything from existing coral ecosystems, ReCoral’s non-invasive approach relies on the collection of surplus coral egg bundles that wash up on shorelines and would not otherwise survive.
Concrete test substrate of the pilot experiment showing the successfully settled ‘coral babies’ attached to it (small white dots)
Coral spawn is buoyant and gets washed up on the shoreline, shown here in the characteristic ‘pinkish’ colour
Coral spawn washed up on the shore has already been prepared to undergo metamorphosis and develop into larvae. Pictured, a cell undergoing metamorphosis
‘We’re excited to take part in such a great initiative and partner up with the world’s most significant player in offshore wind,’ said Hern-Yi Hsieh, director of Penghu Marine Biology Research Center.
‘Environmental protection and marine biodiversity will continue to be one of the key topics of the world in the coming decade.
‘It’s great to see that, apart from its effort to supply clean energy, Ørsted is also launching its coral project here in Taiwan to promote environmental friendliness.
‘We’re honoured to participate in the project, and we look forward to more such initiatives in the future.’
Last year, researchers successfully grew juvenile corals on underwater steel and concrete substances at a quayside test facility. Pictured are these quayside test substrates
Pictured is a coral larvae rearing container filled with filtered seawater equipped with oxygenating and water circulating equipment
Every year, coral spawn spreads throughout the marine environment and washes up on the shore. Here, a researcher is seen collecting coral spawn
If the proof-of-concept trial is successful, Ørsted will explore opportunities for scaling up the initiative, such as to other wind turbines.
Hopefully, it will work on offshore foundations of any kind in tropical waters around the world, such as the Great Barrier Reef.
Australia’s famous Great Barrier Reef suffered yet another significant coral bleaching event, experts confirmed earlier this year – its fourth in just seven years.
GREAT BARRIER REEF SUFFERS WIDESPREAD CORAL BLEACHING FOR THE FOURTH TIME IN SEVEN YEARS
Australia´s Great Barrier Reef has suffered widespread and severe coral bleaching again due to high ocean temperatures, only two years after a mass bleaching event, a government agency said on March 18.
The report comes from the Great Barrier Reef Marine Authority, which manages the world´s largest coral reef ecosystem.
The reef has suffered significantly from coral bleaching caused by unusually warm ocean temperatures in 2016, 2017 and 2020. The previous bleaching damaged two-thirds of the coral.
FILE – In this photo provided by the Great Barrier Reef Marine Park Authority small fish school in waters of Ribbon Reef No 10 near Cairns, Australia, Sept. 12, 2017. Australia’s Great Barrier Reef is suffering widespread and severe coral bleaching due to high ocean temperatures two years after a mass bleaching event, a government agency said on Friday, March 18, 2022. (J. Sumerling/Great Barrier Reef Marine Park Authority via AP)
The environmental group Greenpeace said the severe and widespread coral bleaching suffered during a La Niña weather pattern that is associated with cooler Pacific Ocean temperatures was evidence of the Australian government´s failure to protect the coral from the impacts of climate change.
‘This is a sure sign that climate change caused by burning coal, oil and gas is threatening the very existence of our reef,’ Greenpeace Australia Pacific Climate Impacts Campaigner Martin Zavan said in a statement.
In July last year, Australia garnered enough international support to defer an attempt by UNESCO, the United Nations’ cultural organization, to downgrade the reef’s World Heritage status to ‘in danger’ because of damage caused by climate change.
But the question will be back on the World Heritage Committee´s agenda at its next annual meeting in June 2022.
The Great Barrier Reef has now seen five mass bleaching events – 1998, 2002, 2016, 2017, 2020 and 2022. Mass bleaching events span tens or even hundreds (and sometimes thousands) of kilometers.
They can affect entire ecosystems and are a significant cause for concern for coral reef managers and scientists.
The Great Barrier Reef’s outlook remains ‘very poor’ despite coral recovery over the past year, Australian government scientists said in July 2021.