From the importance of coral reef conservation to the most innovative methods for coral restoration, we are excited to have Marc back for part II of his coral restoration blog series. To find out about all the latest methods for coral restoration then read on. And of course, if you haven’t managed to read his first then blog then check it out here.
The most innovative methods for coral reef restoration
In recent decades, active coral restoration has become more refined and developed as we look to the scientific community to alleviate the pressures humanity places on coral reefs while we wait for impactful changes at a global level.
As someone who works as a coral restoration researcher in the Maldives, a country on the front lines of the battle against climate change, I’ve compiled what I consider to be the future of coral restoration, our best chance to keep reef ecosystems from collapsing as the slow process of institutional environmental change grudges along.
The coral restoration classic — asexual propagation with a nursery phase
Coral polyps reproduce both sexually and asexually. Marine conservationists have been farming corals by fragmenting healthy colonies (taking a small part of a big coral) and growing them in ideal conditions for a coral. We call this a nursery, where the fragments can grow happily in favourable conditions, either in a water floating rope nursery or in a laboratory on land.
After about a year in the nursery, the corals are mature enough to be planted back onto the reef using an underwater adhesive, literally gluing them onto hard substrate. After a while they grow over the cement or epoxy, and it’s like they were there all along.
Sometimes after local development and construction, or blast fishing, there’s no longer a reef or any hard substrate to attach corals to. This is when a reef is said to be “shifting”, and the classic method doesn’t really work because as the reef shifts down the slope, the rubble will destroy any natural or planted colonies over time.
This is when artificial structures are extremely useful. Corals are placed on the structures, away from the sediment and predators, and the structures themselves can stop the reef from shifting. Structures can be designed in any way, and form beautiful underwater parks that attract marine life and tourists.
A particularly intelligent and creative artificial structure, Biorock works by applying a low voltage electrical current through the seawater causing dissolved minerals crystallise on a metal structure, growing into a white limestone that is similar to the minerals that corals use for their skeleton. This can help the coral grow up to 5 times faster than natural colonies for effective coral restoration.
This technology is particular well suited to counter the threats of increased temperatures and ocean acidification as the electrical field provides a low pH that corals like and as less energy is needed for growth, they can better cope with other environmental stresses.
Saudi Arabia’s 3-D printed reef
Saudi Arabia is in the mist of developing a luxury tourist destination along the Red Sea coastline. In a coordinated effort to ensure sustainability through regenerative tourism, a new technique has been developed by scientists at KAUST (King Abdullah University of Science & Technology), trademarked as “Maritechture”.
Live corals are scanned and coral skeletons are 3-D printed or cast from moulds. Special organic polymers that help corals grow are sprayed onto the printed skeleton. Fragments of different coral species with high temperature and salinity tolerance are implanted onto the coral skeleton to create hybrid corals.
These corals are transplanted onto tiles equipped with microchips that gather data to assess the corals health. The tiles are set to be assembled on tripods made from natural materials like volcanic ash and limestone, which can be deployed underwater to form stunning artificial reefs that are great for tourism and the environment.
To see more photos of this particularly ingenious method for coral restoration, scroll to the bottom!
Many feel that the future of coral restoration lies in our ability to manipulate the genetic constitution of corals. Much like the project underway in the Red Sea, making hybrid corals that have temperature and salinity tolerance may be essential for the survival of corals.
Scientists are even testing changing the microbiome of corals (adaption by changing the bacterial community living in the tissues), they’re even storing genetic material in biobanks.
Lots of conservation projects also focus on rearing coral larvae but manipulating different species of coral to reproduce sexually; increasing the genetic diversity of a reefs helps it become more resilient. SECORE tetrapods contain sexually reared coral larvae, and are uniquely designed to be wedged into gaps and crevices of a reef.
The future of coral restoration
With all these remarkable innovations, will they be enough to maintain the health of coral reefs as we try to reduce emissions?
Optimistically, there’s hope that we keep innovating intelligent ways to keep our coral reefs alive. With the proper funding and management, perhaps we can rebuild entire coastlines with thermally tolerant species of corals.
It’s difficult to be optimistic about the future however when governments have consistently failed to meet international climate agreements, and with more pressing issues around the world, there’s always a reason to postpone moving forward with environmental legislation.
A fact about our planet that always depresses me: If we assume the global area of reefs is around 300,000km2, and cost of artificial restoration is $10 per square meter, it would cost just over $3 trillion to restore all of the reefs in the world. Assuming that only a fifth of these reefs are impacted by human activity, then it would cost around $600 billion – the yearly budget of the US conservation budget.
Coral restoration is an important practice that we must keep improving on, but for now it’s just a temporary plaster on a permanent wound.