3D-printed coral could help restore the Great Barrier Reef

By Betsy Verecky

The Great Barrier Reef is one of the seven natural wonders of the world. But lately, it hasn’t looked that way.

Every year, tourists flock to Australia to snorkel along the reef, marveling at its brilliant colors and the marine life that calls it home. However, in recent years, rising sea temperatures, overfishing and pollution have bleached the once colorful coral a ghostly white. While corals used to bounce back from these extreme bleaching events, that is no longer the case, research shows.

The Great Barrier Reef. Photo by Manny Moreno/Unsplash.

“Corals are quite sensitive to temperature rise,” says Charlotte Hauser, a bioengineer and chemist at King Abdullah University of Science and Technology in Saudi Arabia. Pollution, chemicals, oil spills and tourist are all factors that impact the health behavior of corals, she explains, noting that “temperature is one of the major ones.”

In fact, according to the Intergovernmental Panel on Climate Change, a 1.5°C increase in water temperatures over the next century could lead to a loss of 70-90% of reef areas. Meanwhile, the Global Coral Reef Monitoring Network estimates that 14% of the coral reefs around the world have been decimated specifically due to hot ocean temperatures. And, unfortunately, corals take a long time to regenerate after they die. The National Oceanic and Atmospheric Administration estimates that massive corals have growth rates of 0.3 to 2 centimeters per year and that, depending on their size, reefs and atolls (ring-shaped coral reefs) can take as long as 100,000 years to 30,000,000 years to fully form.

Australia’s Great Barrier Reef contains the largest coral reef system in the world, but corals exist all around the world and play a crucial role in biodiversity. They help curb local flooding and support 25% of all marine creatures, the Environmental Protection Agency estimates. They are also home to 4,000 kinds of reef fish, 840 species of corals and 1 million types of other animals, according to the Coral Reef Alliance.

Hauser and a team of researchers are aiming to revive the world’s coral reef population, working on a project with corals in the Red Sea that uses 3D technology to replicate them at a much faster rate. The research—funded by King Abdullah University of Science and Technology in Saudi Arabia—uses a technique called bioprinting, which transplants living cells onto 3D-created models to regenerate new, living coral creatures.

Corals can be propagated just like plants

Corals aren’t all that dissimilar from how plants grow and reproduce, Hauser says. “You can cut them, snip them in small pieces like you do with plants,” she says. “You take a leaf or a branch, put it in water, and then suddenly, some roots grow out of it. Coral is similar.”

Hauser and her team used this framework to guide their process. They collected coral from the Red Sea, then used 3D technology to scan each structure to create a new model that could be used to create an entirely new skeleton.

3D-printed coral. Photo courtesy of Anastasia Serin, King Abdullah University of Science and Technology.

3D printing has numerous advantages in this process. It’s cost-effective and has already been used in large-scale projects, such as new home construction. So when you think about using 3D technology to heal the Great Barrier Reef “the size of the state of Texas,” it doesn’t seem that far-fetched to “repair such a huge project so quickly,” Hauser says.

The team’s design uses a silicone mold made with an eco-friendly calcium carbonate ink that the corals can grow on, one with a “very similar surface to a normal coral’s skeleton, slightly a little bit rough.”

Hauser says this material isn’t harmful to the environment. If it decomposes, it won’t damage marine life. “This is something which I feel is super, super important. We don’t want to use metal. We don’t want to use concrete. We don’t want plastic. There’s enough plastic in the ocean.”

Once Hauser created a 3D prototype, she and her fellow researchers added small pieces of living coral to it. They chose coral that could tolerate high heat, using an eco-friendly glue that can be placed underwater and attached to the bleached structures.

Using coral from the Red Sea has an advantage, given its year-round warm water. Any coral that survives in a hot location would be a good candidate to transplant to other areas of the world. Currently, the team is focusing on growing coral in aquariums, but they hope to successfully transplant their 3D coral directly into the Red Sea.

“Given the overall rise of temperature in the ocean, you need a species that can tolerate a warmer climate, and the Red Sea has an advantage because it is in a warmer area,” Hauser says.

Putting it out to sea

The team’s new hybrid corals can grow much faster than natural corals—in months, not decades. One challenge, however, will be figuring out whether the high-heat corals can grow with different strands once transplanted into the Red Sea.

“There might be certain types that don’t like each other and don’t grow together,” Hauser says, “so even these things need to be considered.”

Close-up of 3D-printed coral. Photo courtesy of Anastasia Serin, King Abdullah University of Science and Technology.

Researchers have been growing these corals for two years in aquariums. The next step is to transplant them into the ocean. They initially tried to do this too fast and realized that the corals needed a longer time period to grow. Once they waited longer for the corals to grow in aquariums, evidence showed that it was a success: The corals were able to grow new tissue.

Transplanting these corals in the ocean shouldn’t be too difficult, Hauser says, given that corals are found in warm, shallow water, covering less than 1% of the ocean floor. This means it’s easier for people to transplant them because they won’t have to dive down to the bottom of the ocean.

In terms of how the corals will be transplanted, the hope is that the team will be able to make larger 3D models on land, assemble them outside of the water, and then place them in the ocean. She noted that underwater 3D printing could be a possibility in the future, minimizing an extra step. The team is also looking at whether it’s possible to 3D print the actual new tissue that these hybrid corals make when they begin to spread.

“The study is ongoing, but it looks like the [eco-friendly calcium carbonate ink] material is really supporting the growth very, very well,” Hauser says. “We have tanks where we can put the coral in and observe it every day, but obviously the proof will be putting it into the sea” after the corals have grown to a certain age and size.

Five years from now, Hauser thinks they will have completed the construction of a 3D reef in the ocean. Hauser is also noodling on another idea that would cover coral with an eco-friendly protective film that could keep coral cool and protect it from bleaching during a heatwave. “We have plenty of things to explore for the future.”

Lead Photo courtesy of Anastasia Serin, King Abdullah University of Science and Technology

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