Curbing the tide of coral degradation

In 2014 Vriko Yu, a biological science student, was studying coral degradation in Hong Kong, when a red tide swamped the marine park. A red tide is a particularly harmful algae bloom – a thick brown layer of organic matter – and is triggered by a rise in water temperature and pollution. So, when Yu dived into the water she shifted from sunshine to near darkness. All she could see was sand and dead sea creatures; and after two months the coral community she was studying had completely vanished. “That was an epiphany for me,” Yu explains. “I thought climate change was happening at a pace that would take decades… but it was happening a lot faster.”

Since corals lack roots, they are particularly vulnerable to sedimentation. To address this, experimentation involved using traditional materials such as concrete blocks, metal bars and PVC pipes to support new coral communities. These communities are often populated with ‘corals of opportunity’, fragments of surviving corals collected from the seabed. Despite these efforts, the team experienced mixed results over several years. “We realized that if traditional methods were not fully effective, it was time to innovate,” says Yu.

In Hong Kong in 2020 Yu founded Archireef, a nature-tech startup that expanded to Abu Dhabi two years later and which is dedicated to the restoration of degraded marine environments. The company has developed the world’s first 3D-printed Reef Tiles, hexagonal clay blocks optimised to function as a foundation for new coral communities. The tiles boast a number of innovations, primarily the complex pattern on its surface; an example of biomimicry design, inspired by an existing brain coral called platygyra, that creates grooves in which coral can be planted and hold firm as it grows.

The 50cm-wide hexagonal tiles also lend themselves to modular construction, making it easy for divers to assemble or relocate the tiles while working underwater. Unlike plastic or metal, which leak toxic chemicals, the clay tiles are made from natural materials and are PH neutral. A single diver can deploy up to 40sq m of Reef Tiles per day, and Archireef monitors the reef for a minimum of three years, providing valuable data and ensuring ongoing ecological support. It is a slow process, but one that bears fruit. The survival rate of coral on Archireef tiles is 95 per cent, says Yu, which is at least four times better than traditional reef restoration methods.

Archireef started as a team of three. Since it became operational, it has grown to a team of 30 and deployed 500sq m of reef in the South China Sea and Arabian Gulf. Its business model is focused on B2B and government contracts, pitching within the context of growing pressure on states and businesses to invest in conservation initiatives. Clients include Asia-region hotel groups that are looking to benefit from reef eco-tourism, as well as boosting their sustainability credentials – and oil and gas companies that are eager to go beyond just net zero and engage with, as Yu describes it, “nature positivity”. 

Yu does not have a business background. This, she admits, has been a challenge at times, but she has benefited from the expertise of her co-founders David Baker, an experienced marine ecologist and Deniz Tekerek, who has a background in establishing and growing startups. Archireef is a commercial enterprise but it will not facilitate short term projects motivated by PR. It guards against more cynical uses of its products by expecting clients to invest properly in the initiative. Its reef deployment service – which is called Build-a-Reef and includes the installation of a reef of any size – comes with a minimum three-year subscription in which Archireef monitors and maintains the reef. “We need to see the impact and the result, and make sure that our client is not just seeing this as an exercise or a one-year programme, but rather as a long-term commitment,” says Yu. The startup won’t share financials, but says growth is strong – even more so since COP28, held at the end of 2023.

Driven to help counter the impacts of climate change, Yu also wants Archireef to preserve coral within an evolving planet. Typically, coral exists in tropical climates, but as sea temperatures rise and tropical waters become inhospitable, subtropical regions are increasingly viable, which is why focusing on the waters around Hong Kong and Abu Dhabi makes sense to her. “That subtropical belt is providing a refugia for coral to migrate to,” she says. “I think it’s important to buy yourself that silver lining to make sure that we are able to secure the future of corals in light of climate change.”