A new research project aims to restore damaged reefs faster than ever, utilizing 3D-printed skeletons made of the same material as the real thing.

First of all, there have been other projects that attempted to encourage the regrowth of coral by placing artificial skeletons on existing reefs. In most cases, though, those skeletons were made of materials such as concrete or polymers.

This means that waterborne coral polyps arriving at the reef have had to secrete calcium carbonate onto the structures, in order to "make them their own." Given that some corals grow at a rate of just a few millimeters per year, it can take quite a long time to rebuild reefs in this fashion.

Seeking to speed things up, scientists at Saudi Arabia's King Abdullah University of Science and Technology (KAUST) have developed a technique for producing skeletons made entirely of calcium carbonate. Known as 3D CoraPrint, the process begins with a 3D scan being performed on a natural coral skeleton. From there, either of two printing methods can be used.

In one scenario, the resulting 3D computer model is used to print a replica of the skeleton, made of an ordinary material such as plastic. That model is then used to create a silicone mold, which is subsequently filled with an "eco-friendly and sustainable" calcium carbonate ink. Once that ink cures in response to exposure to light, the finished calcium carbonate skeleton is removed from the mold.

The other option is to simply 3D-print the replica skeleton directly out of the calcium carbonate ink, which cures as it's deposited on the print bed. In either case, the finished product is then seeded with small fragments of live coral, in order to jumpstart the polyp colonization process once the artificial skeleton is placed on the reef.