Overfishing, pollution and climate change are pushing the ocean’s coral reefs to the brink of extinction. Depending on the region, average declines in coral reef cover can range from 40 to 80 percent. And a recent study reports that reefs may be eradicated entirely in the lifetime of a child born today if steps aren’t taken to reduce ocean acidification.
In an effort to restore that lost ocean life, Reef Arabia, a group of marine biologists in the Middle East, is using 3-D printing to manufacture synthetic reefs and deposit them on the Persian Gulf floor. The gulf is no stranger to mass coral death: According to the World Resources Institute, rampant offshore and coastal developments in Bahrain have contributed to depletion of coral reef cover in the waters there to almost 0 percent.
Reef Arabia has been using concrete molds to create artificial reefs in the region for some time. (Reefs aren’t just good for coral; they provide crucial habitat for tropical fish as well as other ecosystem benefits.) Three thousand of its trademarked “Reef Balls” have already been sunk in the gulf. Now, after partnering with U.K. company D-Shape, the group has begun 3-D printing of more-refined reef formations.
David Lennon, director of Sustainable Oceans International and a member of Reef Arabia, told Forbes, “With 3D printing we can get closer to natural design because of its ability to produce very organic shapes and almost lay down material similar to how nature does it.”
Whereas the Reef Balls look like perforated half-domes, the printed reefs, made out of a patented sandstone material, closely resemble living coral. That bumpy, knobby texture attracts the species that use it as a refuge, and its horizontal surfaces attract coral larvae. The hope is that printed reefs will be more effective than concrete models at fostering biodiversity, a crucial component in making ecosystems more resilient against the effects of climate change.
Two prototype printed reefs, each weighing 1,100 pounds, were submerged off the coast of Bahrain last fall. While the group reports on its Facebook page that those reef units are thriving with invertebrates and algae, it’s still too early to tell if they’ll become more biodiverse than their concrete counterparts.
The printed prototypes took about a week to fabricate from scratch, though the actual printing took only about a day. If it goes into wider production, Reef Arabia expects to be able to print four reef units at a time.
But while the idea of using 3-D printing to replace a vital element of our oceans is a seductive one, it shouldn’t be mistaken as a cure-all for coral decline.
Michael Webster, executive director of Coral Reef Alliance, says most people forget that corals are the invertebrate animals that build these rock structures. “If the problems that are causing the decline of the corals aren’t addressed,” he says, “just putting in an artificial reef isn’t going to get us what was once there. It’s never going to get a structure that grows on its own, that can regenerate on its own. What we should be striving for is creating conditions for corals to thrive.”
Webster adds that artificial structures can have a place in coral restoration—if they’re used in conjunction with meaningful actions that address the causes of the animals’ decline, such as climate change, overfishing and ocean acidification.
Otherwise, he says, “you’re not creating a coral reef; you’re creating a habitat for certain species. You can put down structures that attract fish and create an ecosystem, so you get some of the value from them, and that’s not without merit. But it’s not the same thing as restoring a reef.”