According to New Atlas, coral reefs are made up of hard, porous "skeletons" inhabited by tiny polyps. A new research project aims to restore damaged reefs faster than ever before, using 3D printed skeletons of the same material as the actual thing.
First, there have been other projects that have tried to get corals to grow back by placing artificial skeletons on existing reefs. In most cases, though, these skeletons are made of materials such as concrete or polymers.
This means that aquatic polyps that reach coral reefs have to secrete calcium carbonate onto these structures in order to "make them their own." Given that some corals grow at a rate of only a few millimeters per year, rebuilding coral reefs in this way can take quite a long time.
To speed up the pace, scientists at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia have developed a technique for producing a skeleton made entirely of calcium carbonate. The process, known as 3D coraprint, begins with a 3D scan of a natural coral skeleton. From there, you can use either of the two printing methods.
In one case, the resulting 3D computer model was used to print a copy of a skeleton made of common materials such as plastic. The model was then used to create a silicone mold that was subsequently filled with an "eco-friendly and sustainable" calcium carbonate ink. Once the ink solidifies under light, the finished calcium carbonate skeleton is removed from the mold.
Another option is to 3D print the skeleton of the replica directly with calcium carbonate ink, which solidifies as it is deposited on the print bed. In either case, the finished product is injected with small pieces of live coral fragments to initiate the colonization process when the artificial skeleton is placed on the reef.
According to the researchers, both printing techniques have their advantages and disadvantages. If a mold is created, many skeletons can be cast from that mold in rapid succession, but they must be relatively small in order for the ink to solidify. Direct 3D printing takes longer, but can make large skeletons of various shapes.
"With 3D printing and molds, we can both gain flexibility and mimic what has already happened in nature," said Zainab Khan, who led the study with Charlotte Hauser and Hamed Albalawi. "Structures and processes can be as close to nature as possible. Our goal is to promote this. ”
The study was described in a paper recently published in the journal ACS Sustainable Chemistry and Engineering.