3D-printed terracotta coral reefs could save the ‘rainforests of the sea'
The artificial corals mimic the natural complexity of a reef and aim to attract marine organism to support the regrowth.
Researchers in Israel have developed a method of 3D printing corals to help regrow bleached reefs. We spoke to Natalie Levy, a PhD candidate at the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University to find out more.
Why are corals so important to the ocean ecosystem?
Corals are often called the rainforests of the sea. They are the habitat for a number of organisms from the smallest creatures, such as small invertebrates that build the reef to huge commercial fishing species. All life - microbes, small animals, everything - depends on the coral reef. They’re hugely important for coastal communities, for livelihoods, for the economy, for tourism. Corals also help to break waves so that they don't erode islands and coastal cities. Whether directly or indirectly, we are all in some way benefiting from corals.
What does the structure of a reef look like?
If you strip away all of the coral and the sponges and different things that make up the reef, you're left with something that’s almost like a piece of rock - pretty much a kind of substratum that sits in the ocean. But as corals and other reef-building creatures settle and start to grow on this structure, they start to build and form the reef.
Existing artificial reefs have difficulty replicating the complexity of coral habitats and hosting reef species that mirror natural environments. What we're doing in our research is basically extracting the core characteristics of a reef by using 3D imaging and modelling. If you imagine throwing a blanket over the reef, you’d see the shape of the blanket. We’re basically taking this shape and mimicking it.
How do you scan the reefs?
Our partners from the University of Haifa have taken thousands of underwater images that they have stitched together in imaging software to create a model. This model is a realistic computer model of the exact reef. It is extremely accurate and has fine-scale details. You can move it around, you can zoom in on it, everything like that. And also you can tag and label different coral species.
We partnered with a 3D-printing and design team from the Technion – Israel Institute of Technology to translate information and put it into computer-aided design software, which can then be read by the 3D printer. The printer will basically interpret whatever design we give it - it will try to create the same complexity and detail as the design that we fed it.
How does the printing process work?
So 3D printing comes from an industry term called additive manufacturing. It's as simple as it sounds. It's literally adding and building layers on top of each other. So the printer will start layering the outline of the structure and will continue to build upon that. It layers it in hexagon shapes. The printer knows how it should interpret the design and how it should add the layers of material.
We use terracotta clay that becomes ceramic when you fire it in the kiln. Once it's fired in the kiln it maintains its porosity, which is very important for an underwater structure, and then it has similar properties to the actual coral skeleton.
What success have you seen so far?
We've deployed these reefs in the Gulf of Eilat in the Red Sea. At the moment, we're still in the phase of monitoring and collecting data. We’ve deployed 3D-printed ceramic tiles made from the same material, using the same process, just not such complex, massive structures.
We wanted to do a study to understand how the reef organisms would interact with the material, how they’d settle on the structure, what kind of species are were able to get to settle on it, such as the same species you’d get in a natural coral reef etc.
It's been known for a while that the ceramic terracotta is a great material for coral organisms and the methods we're using have been working great. We found that we were able to see all the main reef building organisms, a lot of coral, soft corals, other organisms that were the same as the ones seen in the reef that we put them in.
We've been monitoring those structures with photography and soon we'll do our first monitoring period of them with environmental DNA. Hopefully we will see the same - more enhancement [of the reef] and a bigger increase in biodiversity than if you just put a block of concrete or something in the water.
So this technique also has the ability to be rolled out in multiple regions?
That's the idea. We wanted to implement an algorithm and a model that could be employed for any coral reef that needs this kind of technology. So you could go and take 3D scans or models of reefs in Colombia or Panama or Brazil or Hawaii.
People also are working on the 3D modelling technology, the 3D imaging. It's something that institutions are currently implementing. You can download the models from the Internet for free. For example, I could take the models and build you a reef. Anyone can do the exact same process. So if people need it for helping their coral reefs they can use the technology wherever they are.
What's next for the project?
Well, the dream is, if we can get some big funding, we would like to implement this project in several coral reefs all over the world. Our philosophy is that we want to help all coral reefs that are degrading. The idea is to have a massive coral reef restoration project using our structures for wherever people need to add to reefs, to allow corals to settle and to grow. People anywhere in the world could use our technology. We're really looking for people that are able to help us, to work with us, to help to contribute to the dream of protecting the reef.
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Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.