If you dive off the coast of Israel at a beach near the city of Eilat, you might come across a tall pole underwater covered in donut-shaped attachments. It doesn’t look like a coral reef. But the researchers who 3D printed the structure are hoping that it could be used for rebuilding diversity in areas where reefs are dying.
“As a diver, I was seeing the early signs of this five years ago,” says Ezri Tarazi, an industrial design professor at the Technion—Israel Institute of Technology, who is collaborating with other researchers from his university, Ben-Gurion University of the Negev, and Bar-Ilan University on the project. “I was thinking, how can we take a reef that’s totally collapsing—which means there are no branches of corals anymore because they collapse, and fish cannot hide—and how can we reignite life in it? Because I’m an industrial designer, the idea to print corals was the first thing coming to mind.”
Reefs are disappearing for multiple reasons, including dynamite fishing that blasts fish to the surface and turns coral into rubble, toxic chemicals in sunscreen, invasive fish, and, crucially, climate change, which is making it harder for reefs to survive as the water gets hotter and more acidic and sea levels rise. At the beginning of 2019, coral cover in parts of the Great Barrier Reef was at record lows. Heat waves in 2016 and 2017 killed huge swaths of coral there; 30% of the coral died after the heat wave in 2016 alone. If the average global temperature rises 2 degrees Celsius, 99% of coral reefs will be lost—and that will decimate part of the food system, since reefs are crucial nurseries for fish that feed more than a billion people around the world.
Using a 3D printer to build a structure to replace part of a damaged reef can’t tackle the underlying problems facing reefs. But it could potentially help support fragile ecosystems in areas where reefs have been so damaged that they aren’t likely to regenerate on their own. The Israeli researchers aren’t the first to take this approach. Reef Design Lab, founded by an Australian industrial designer, installed the world’s largest 3D-printed reef in the Maldives last year, taking advantage of the technology’s ability to recreate natural shapes.
The new design now being tested in Israel looks less like coral, but is similarly complex, says Tarazi. “It can create large variety and complexity,” he says. A computer program generates differences in the design so that each printed part can attract different types of fish. The design uses a cheap material, a ceramic made from local clay. The structures can be quickly installed and then planted with coral.
It’s not a complete solution; if there aren’t enough living corals on a structure, it won’t be able to grow to keep up with sea-level rise. It would be expensive to do over large areas. Other approaches, like farming coral on land and then replanting it underwater (something that could be combined with artificial reefs, in some cases), are also difficult to do at a large scale, though researchers are working on technology like coral-planting robots. Some experts argue that this type of work could take money away from proven strategies like patrolling marine protected areas.
Ultimately, the world needs to tackle the underlying problem of climate change. But it’s also true that we need solutions now. When I spoke with Tarazi, he had just emerged from a dive to look at the test site. “What I’ve seen over the last three days is something that I’ve never seen, ever,” he says. The temperatures on his dive computer were higher than they had ever been, at 84 degrees Fahrenheit, when the water is usually around 73 degrees. It’s a clear example, he says, of the way water is heating up around the world, and the urgency of finding ways to protect coral, which is sensitive to even small changes in temperature. The research team hopes to eventually build a large 3D-printed garden in the area. “We want to make it as a kind of test for really constructing a dead reef,” he says.