Few people realize that, despite its reputation as a concrete jungle, Hong Kong is one of Asia's most bio-diverse cities, with more hard coral species than the Caribbean. However, pollution and growing urbanization pose a threat to these corals.

Coral reefs, which are found in warm, shallow water, cover less than 1% of the ocean floor yet are home to more than 25% of all marine species and. They have been present in Hong Kong for thousands of years, but pollution and coral mining have decimated the population.

ArchiREEF, a Hong Kong University spin-off, claims to have a solution: 3D-printed terracotta tiles that help corals grow and restore ocean life. The company, which was co-founded in 2020 by marine biology professor David Baker and PhD student Vriko Yu, wants to make corals "more resilient" to climate change.           

Since 2016, Baker and Yu have been working with the Agriculture, Fisheries, and Conservation Department (AFCD) to rebuild coral at Hoi Ha Wan Marine Park. The crew needed to lay a new foundation on which the corals could develop. They began creating an artificial coral reef utilizing the university's 3D printing facilities.

This artificial reef is comprised of two-foot-wide tiles that replicate the natural shape of platygyra, sometimes known as "brain coral." According to Yu, the twisting "valleys" attract marine species that can nest or hide from predators. The team uses non-toxic glue to connect newborn corals to the tile once it has been placed in the water. The tile's design encourages corals to grow vertically, attracting marine species that makes their homes in reefs.

In the summer of 2020, more than 130 of these tiles were put on the seabed in Hoi Ha Wan Marine Park, and archiREEF was created.