Coral reefs are a vital part of our marine ecosystem, help protect coasts against flooding and provide food, income and protection for more than half a billion people around the world.
Yet rising sea temperatures and ocean acidification – both of which can be attributed to climate change – are affecting reefs around the world, leading to bleaching events, where entire coral reefs are killed. The figures are staggering: between 2009 and 2018, the world lost about 14 per cent of the coral on its coral reefs, equal to roughly 11,700 square kilometres.
It is fitting that this year’s COP is being held in Sharm el-Sheikh, home to one of the longest continuous living reefs in the world. The Red Sea is home to five per cent of the world's coral reefs, including more than 350 types of coral. Yet, like all coral reefs around the world, it is under threat.
One group looking for a tech-based solution to these threats is Archireef, a startup on a mission to restore marine life in the coral reefs near Hong Kong. Launched by a team of University of Hong Kong scientists in 2020, the company’s co-founders – CEO Vriko Yu and CCO Deniz Tekerek – explained the challenges they faced at the Global Climate Action Hub at COP27.
Clay Solutions
“We started by using traditional methods like concrete blocks, metal rebar and plastic frames,” Yu says. This led to “four years of failure,” she says, as when they would return to the reefs, they found either the artificial coral detached, or the real coral had died.
That led the team to think like a coral, Yu says. “The first thing they need is material compatibility, so we know corals does well with natural material like clay. The second thing they need is complexity, so they can sustain life, and the third thing they need is roots, so they can stabilize on the sea floor.”
These were the elements that led to the creation of the world’s first 3D-printed coral reef tiles. The process is as follows: Local publicly available ecological data is fed into an algorithm; the algorithm defines the design of the tile’s top layer; the top layer is 3D-printed in clay and attached to the tile’s standardized base.
The reefs are also designed to prevent sedimentation build-up, which is one of the major threats facing coral reefs. Each tile is about 50cm across and weighs about 15kg. “We select sites where there is limited life and so end up picking areas of barren sea floor,” Yu says.
While artificial coral reefs are not new, the use of algorithms and 3D printing allows for coral reef’s natural structure to be imitated, which results in more marine life growing.
So far, there is a 98 per cent survivorship rate of the areas Yu’s team has installed the reefs, while the algorithm-based approach allows for fast scaling in multiple locations.
The tiles are mounted on ‘feet’ that raise the coral from the seabed, allowing them to grow higher and access more light and nutrients.
The team first chose three sites in Hoi Ha Wan Marine Park in northeast Hong Kong, which include a coral beach, Moon Island and a sheltered bay near the World Wildlife Fund’s marine life education centre. This area was hit hard by a 2018 super-typhoon which resulted in the destruction of 80 per cent of the corals in Hoi Ha Wan Bay.
Other companies are joining this space too. Reef Design Lab, an Australian company has designed the largest 3D coral reef in the Maldives, which uses concrete. However, terracotta clay – which Archireef is using – is more eco-friendly and is non-toxic to marine life.
And while no one thinks that 3D printing alone can save coral – ultimately the only thing that will save global reefs is a reduction in carbon dioxide emissions – it can play a small but important role in this most vital of ecosystems.
Archireef presented their climate solution at the Action Hub in Sharm el-Sheikh – Watch their event here.