3D printed terracotta ‘reef tiles’ to repopulate coral communities

Researchers at the University of Hong Kong (HKU) developed specially designed 3D printed ‘reef tiles’ for attachment by corals to enhance their chance of survival.

The tiles were developed for use in the Hoi Ha Wan Marine Park in Hong Kong, a local biodiversity hotspot accounting for more than three quarters of reef-building corals in Hong Kong and more than 120 fish species. In recent years, gradual deterioration, also known as bioerosion, combined with coral bleach and mass mortality events in 2015-2016, put the coral at risk.

The 3D printed terracotta tiles, designed by a team of architects and marine scientists, are especially designed to aid coral restoration by providing a structurally complex foundation for coal attachment and to prevent sedimentation, one of the major threats to corals.

The tiles were ‘planted’ in July 2020, seeded with the three coral species common in the park (Acropora, Platygyra and Pavona). Each has a different growth form to create a diverse habitat for other marine species.

In total, the team printed 138 tiles of 600mm using a robotic 3D clay printing method with generic terracotta clay, which were fired at 1125 degrees Celsius. The design was inspired by the patterns typical to corals and integrated several performative aspects addressing the specific conditions in Hong Kong waters.

In addition to the novel design of the tiles, the materials used are more eco-friendly than the conventional use of concrete and metal. The team plans to expand their collaboration to new designs with additional functions for seabed restoration in the region.

The aim of the project is to help restore corals and conserve biodiversity more efficiently. The researchers will monitor in the next year and a half.

Photos: HKU