Coral reefs are important to the millions of species that live in them as well as humans, protecting coastlines from storm surges and offering income from tourism and fishing. Half of the world’s coral reefs have died in the last 30 years, and 90 percent of the world’s remaining reefs are at substantial risk of dying within the next 100 years if nothing is done. They are suffering mainly from climate change, overfishing and damage from boats.

3D printing is an effective way of creating artificial coral reefs, which are then dropped into the ocean, with the hope that free-floating coral polyps will attach themselves to them and grow into new coral structures. The coral will subsequently attract other species that make their homes in reefs, where a new reef will grow from the artificial seed material.

In August 2018, the Reef Design Lab of Melbourne, Australia created the largest ever 3D printed artificial coral reef. 3D printed moulds of the reef structures were made and used to cast the structures in ceramic, which is chemically similar to the calcium carbonate found in actual coral reefs. The 3D printed moulds were printed in Australia, shipped to the Maldives, filled with concrete, assembled at Summer Island and dropped into the ocean; they now rest seven meters below the ocean’s surface. Live coral was transplanted into the reef, where it will hopefully grow and colonize the structure to forming a living reef.

Sunken ships and concrete blocks have been previously used to create artificial reefs. In season 1 episode 10 of Amazon Video original television series The Grand Tour, the presenters travelled to Barbados to experiment with building an artificial coral reef out of 5 car body shells. 3D printing allows the natural structure of a coral reef to be imitated, attracting more marine life. Here, computer aided design was used to replicate naturally-occurring coral reef structures before 3D printing them. The complex shapes of natural reefs are difficult to create any other way, ergo 3D printing is a significant part of creating artificial reefs.

It won’t be known for several years if the experimental reef is working, as it will take that long for the relevant species to populate the structure. It is hoped that the reef will be covered in coral within the next two years.