From 3D-printed tiles to sunken statues: 4 innovative approaches to coral restoration

A team of marine scientists from the University of Hong Kong is using 3D-printed tiles to help save endangered coral reefs.

Seeded with coral fragments, the terra-cotta slabs are being used in three locations throughout Hong Kong's Hoi Ha Wan Marine Park. Their impact will be measured for the next two years. Three types of coral have been chosen, according to the University of Hong Kong: Acropora, Platygyra and Pavona, which have different growth forms to create a diverse underwater habitat.

The area is an important biodiversity location, home to more than three-quarters of Hong Kong’s reef-building corals and more than 120 different species of fish.

Those corals are under threat from coral bleaching and other forms of degradation, leading to a collapse of marine life populations. Around the world, coral reefs are a vitally important habitat for an estimated 25% of all sea life, yet they only take up around 1% of the ocean floor.

The tiles will cover an area of approximately 40 square metres in total and were developed jointly by marine scientists and architects at the university. They have been designed to contain ridges and indentations that will mimic the kinds of environment where coral reefs naturally occur.

This is just one approach to helping restore coral reefs, which have been badly affected by rising sea temperatures and ocean deoxygenation. According to the International Union for Conservation of Nature: “Oxygen loss from warming has alarming consequences for global oceanic oxygen reserves, which have already been reduced by 2% over a period of just 50-years (from 1960 to 2010).”

The chief source of this problem is climate change, which is the greatest threat to coral reefs and many other marine habitats, while increasing levels of carbon dioxide in the world’s oceans is leading to acidification.

Here are some of the other innovative projects working to save coral reefs around the world.

Automated coral seeding

Off the coast of Western Australia, work is underway to protect the Scott Reef, which suffered losses in a 2016 bleaching event that has been described as one of the worst of its kind.

In a joint initiative between marine scientists and the tech company, Autodesk, a project called Coral Maker has been developed to scan, design and create pre-made coral skeletons. These will then be seeded with live coral material, using automation techniques more commonly seen in factories.

Underwater statue

In the waters off Thailand, a slightly different approach has been taken toward rebuilding reefs. A series of specially made structures, including statues, have been left on the seabed for marine creatures to inhabit. These include a giant sculpture of the sea goddess Mazu, weighing in at 1,800 kilogrammes.

The non-profit organization Global Coralition worked with conservation group Eco Koh Tao, to place dozens of structures containing 5,000 coral transplants in the sea around Koh Tao island.

Reef cubes

While some of the Koh Tao structures are shaped like pyramids, a start-up called ARC Marine has developed a reef cube, to perform the same function. The interlocking cubes contain a series of gaps that create space for fish, crabs, lobsters and others to make their home.

Their chief use is likely to be as part of artificial reefs, constructed near offshore wind farms. Large blocks are frequently placed around the base of turbine towers to provide a stable footing, and there are 40,000 of them in the seas around the UK alone. The ARC Marine cubes are plastic-free and designed to encourage more marine life to become established.