HORIZONS
3D-PRINTED TERRACOTTA REEFS COULD SAVE THE WORLD’S CORALS FROM DEVASTATION
The artificial structures mimic the natural complexity of a reef and hope to attract marine organisms to support its regeneration
WHY ARE CORALS SO IMPORTANT?
Coral reefs are often called the ‘rainforests of the sea’. They’re the habitat for a number of organisms, from the smallest invertebrates to enormous species that are fished commercially. All life – microbes, small animals, everything – depend on the coral reefs.
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’re all in some way benefiting from corals.
WHAT DOES THE STRUCTURE OF A REEF LOOK LIKE?
If you strip away all of the living 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. 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, Israel, have taken thousands of underwater images that they have stitched together in imaging software.
This generates a realistic model of the reef that’s extremely accurate with lots of 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 (CAD) software, which can then be read by the 3D printer. The printer will basically try to create the same complexity and detail as the design that we fed it.
HOW DOES THE PRINTING PROCESS WORK?
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. The printer will start layering the outline of the structure and will continue to build upon that.
It layers it in hexagonal 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 been fired it maintains its porosity, which is very important for an underwater structure. It also 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. We wanted to find out how they’d settle on the structure, what kind of species are able to settle on it, and whether it would be the same species that you’d get in a natural coral reef.
It’s been known for a while that terracotta is a great material for coral organisms and the way we’re using it has been working really well. We knew reef-building organisms would settle on a test reef if we added them, but on the reefs we deployed in the Gulf of Eilat, we’ve seen all the main reef-building organisms settle on them naturally.
We’ve been monitoring those structures with photography and soon we’ll begin monitoring them using environmental DNA. Hopefully we’ll see the same further enhancement [of the reef] and a bigger increase in biodiversity than you’d get if you just put a block of concrete or something in the water.
CAN THIS TECHNIQUE BE REPRODUCED IN OTHER PLACES?
That’s the idea. We wanted to implement an algorithm and a model that could be employed for any coral reef that needs support. So you could go and take 3D scans and build models of reefs in Colombia, Panama, Brazil… wherever it’s needed.
The 3D CAD models can be uploaded to the internet and then are available for anyone to download for free. Anyone with the 3D-printing equipment required can take the CAD models and build a reef. Researchers at other institutions around the world have already started doing this.
WHAT ARE THE NEXT STEPS 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 reefs.
NATALIE LEVY
Natalie is a PhD candidate at the Mina and Everard Goodman Faculty of Life Sciences at Bar-Ilan University, Israel.