In the Face of Climate Change: Saving Coral Reefs with 3D Printing
Michael Molitch-Hou posted on October 15, 2018 |

A combination of human activities has put a number of species of coral on both the endangered and threatened species lists, but as humanity as a whole eradicates these crucial creatures, some people are doing their part to try and restore coral populations around the world. Among them is Alex Goad, whose Australia-based Reef Design Lab is creating artificial structures using 3D printing on which to grow new coral colonies.

Alex Goad’s MARS structure, made with 3D printing. On the left, the structure upon installation in the Maldives. On the right, the structure as it begins to support life. (Image courtesy of Reef Design Lab.)
Alex Goad’s MARS structure, made with 3D printing. On the left, the structure upon installation in the Maldives. On the right, the structure as it begins to support life. (Image courtesy of Reef Design Lab.)
Engineering.com reached out to Goad to learn about what he’s doing to benefit the marine ecosystem and how 3D printing fits in with his company’s work.

The State of Coral

Perhaps best known for the stunning colors and shapes decorating the Great Barrier Reef, coral are crucial to many aspects of life related to marine ecosystems and, thus, the larger global ecosystem as a whole.

These invertebrates live in dense colonies within large, self-made calcium carbonate exoskeletons, which provide shelter for a wide variety of marine life, while also protecting coastlines from waves and tropical storms. In addition to the benefits that their exoskeleton provides, coral act as the source of nitrogen and other nutrients within the marine food web, regulate carbon and nitrogen within the oceans, and play a role in nutrient recycling.

Unfortunately, a range of human activities is actively destroying coral populations around the globe. Most notably are the rising temperatures and ocean acidification associated with climate change. While rising temperatures cause thermal stresses that result in bleaching, the oceans’ massive absorption of carbon dioxide (about a third of total anthropogenic emissions) is decreasing pH levels, which inhibit coral growth and the integrity of reefs. Other climate change-related issues, such as increased sea levels and more intense storms, negatively impact the life of coral as well.

As the Intergovernmental Panel on Climate Change (IPCC) noted in its special report on global warming of 1.5°C, humanity has until 2030 to cut carbon dioxide emissions by about 45 percent in order to keep average global warming at 1.5°C above preindustrial levels. Even at such a high temperature, the IPCC reports that, “coral reefs would decline by 70-90 percent with global warming of 1.5°C, whereas virtually all (> 99 percent) would be lost with 2°C.”

Outside of climate change, humans are also killing coral through such practices as coral mining, pollution, over fishing and runoff from agriculture and urban environments. At least 10 percent of coral reefs have already died, and 60 percent are at risk even before the planet reaches higher average temperatures.

As dire as the picture is, there are many groups doing what they can to protect and restore these vital creatures, including Reef Design Lab.

Artificial Exoskeletons

Goad explained that there are many low-tech methods already being deployed to restore coral populations. Essentially, reef protectors will create artificial coral farms using objects such as pipes, steel lattices or pieces of limestone rock, which then have individual pieces of coral manually attached to them in an effort to successfully cultivate a colony.

These methods have mixed results, but Goad hopes to add a new type of structure to the mix. Working closely with researchers, Reef Design Lab creates organic-looking, complex geometries from materials like ceramic and concrete in the hope that marine life will find suitable nooks and crannies within the structures in which to thrive.

Designer Alex Goad with a MARS module. (Image courtesy of Alex Goad.)
Designer Alex Goad with a MARS module. (Image courtesy of Alex Goad.)
The organization sprang out of Goad’s graduation project while he was obtaining a degree in industrial design at Monash University in Melbourne. The project, dubbed “MARS” for “Modular Artificial Reef Structure,” is made up of parametrically designed, LEGO-like blocks into which coral can be transplanted. The modules are first designed in CAD software before molds are 3D printed on a desktop fused filament fabrication system and the final blocks are cast from ceramic.

In the summer of 2018, this method was used to install the world’s largest “3D-printed” reef in the Maldives. Installed in a region of the ocean where there were previously no coral reefs, MARS serves as a substrate for farmed coral to grow and, hopefully, form a natural reef.

“The head of [the MARS] dive built the coral in this area over the last three years,” Goad said. “He’s built an entire coral farm in his spare time essentially. The corals have had a lot of success growing there because they’re in slightly deeper waters, avoiding a lot of the bleaching events that have been happening in water above certain temperature.

“Essentially, MARS is a fancier version of some of the more traditional techniques,” he continued. “I’m going to be really interested to see if it’s much more effective using a ceramic material. It’s going to be the first large test of this system and it’s kind of the perfect area to do it because we can directly compare it with steel and ropes and limestone rock and the other techniques they’re using.”

Saving Other Sea Life

While MARS is dedicated to restoring coral populations, Reef Design Lab is not solely dedicated to aiding coral. The structures the firm creates also aid in providing habitats for other species.

“The thing about the MARS structure is that, even if it’s not really successful with coral transplants, it has the three-dimensionality that’s important for other species that live on this coral farm, like moray eels. There’s already a moray eel living in the structure,” Goad said.

A sea wall created with Sydney Institute of Marine Science. (Image courtesy of Reef Design Lab.)
A sea wall created with Sydney Institute of Marine Science. (Image courtesy of Reef Design Lab.)
To provide habitats for other species, Reef Design Lab teamed up with Sydney Institute of Marine Science (SIMS) to create a sea wall with built-in crevices for sea creatures to make their homes. Typically, sea walls might be made of flat slabs of concrete to prevent roiling seas from encroaching on and eroding the land. The SIMS project looks into how these structures can be redesigned to accommodate sea life more effectively.

“We’ve come up with a range of different sea wall panels, basically looking at what the ideal geometry is to include in a seawall for increasing oyster colonization for the Sydney Harbor specifically,” Goad said. “When building a new sea wall in the future, instead of making a flat concrete seawall, you could include these strange parametric patterns or water-retaining devices, like rock holes and that sort of thing, to increase the biodiversity on the seawall. Unfortunately, it’s inevitable that we will continue to build into the marine environment, so really Reef Design Lab is looking at what’s a better way to do that. How can we do that and build with nature and for nature.”

Low-carbon sandstone structures designed by Reef Design Lab and 3D-printed by D-Shape. (Image courtesy of Reef Design Lab.)
Low-carbon sandstone structures designed by Reef Design Lab and 3D-printed by D-Shape. (Image courtesy of Reef Design Lab.)
Similarly, Goad worked with the World Wildlife Foundation Netherlands to design artificial oyster reefs for placement into the North Sea. In this case, the reef units were 3Dprinted using Enrico Dini’s large-scale D-Shape 3D printer. A total of 50 different structures with heights ranging from 50cm to 120cm were 3D printed in sandstone, which uses much less carbon dioxide to manufacture than concrete, and installed in the sea, where they will be monitored on an ongoing basis.

“I’m particularly interested in modularity,” Goad said.“It’s fine to 3D print something really large, but how do you implement it? Implementing the MARS project didn’t take heavy cranes. That type of project can all be done by hand. That’s what Reef Design Lab is especially interested in looking at: the whole process of implementing these projects from manufacture to final installation and looking at how we can make that as easy as possible.”

Reef Design Lab is focused primarily on working with researchers, who have the expertise to deploy the firm’s design in the most effective way possible. Goad currently runs the firm by himself, so he is now looking to expand and bring in engineers. He is also into ways to continue developing the MARS structure, including making it more economical to install.

To learn more about Reef Design Lab, visit the firm’s website.


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