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3D printed reefs: Monaco reforms its underwater landscape

Rich in life, but delicate in balance: coral reefs cover just 0.2% of our oceans yet support 30% of all marine species known to date. They are also increasingly under threat. If the natural can’t survive, could science and technology provide a solution?  

At the UN Ocean Conference in June 2017, Monaco’s Prince Albert II called on those present to sign the Coral Reef Life Declaration, saying, “Life above water depends upon the health of life below water.”

Some months later at the Our Ocean conference held in Malta, the principality was joined as a signatory by the nations of Australia, Cook Islands, Fiji, France, French Polynesia, Grenada, Indonesia, Mexico, Niue, Palau, and the Seychelles. But coral reefs are not exclusive to the world’s tropical seas as it would seem by the names of countries supportive of Prince Albert II’s declaration. They can be found all over the world, including in the temperate Mediterranean and, locally, off the coast of Monaco.

A quarter of coral reefs worldwide are already considered ‘damaged beyond repair’ and another two thirds under serious threat, according to the World Wildlife Fund. As with countless sites around the world, Monaco’s own reefs are also sensitive to climatic change, pollution and destructive fishing (among other threats). If Prince Albert is a well-known international activist, the health of coral is as much a domestic concern as it is global.

One of the six large 3D printed reefs to be submerged at the end of 2017. Copyright J M Mille/AMPNEarly experiments

In the mid to late 1970s, Monaco became one of the first coastal sites in Europe to experiment with artificial reefs. From concrete blocks, caves and stacked pyramids to an intentionally sunken wooden boat, the principality’s early efforts were varied – each a precursor to the latest underwater innovation – and carried a special goal.

“Artificial reefs have several functions,” explains Jacqueline Gautier-Debernardi, the director of the Association Monégasque pour la Protection de la Nature (AMPN). “Some are immersed to prevent trawling, others create more attractive diving sites, and some help increase fish stocks.”

In Monaco, however, the artificial reefs were specifically designed to restore habitats damaged by human activity.

Around the same time as these installations, Prince Rainier III created the first of two marine reserves along Monaco’s 3.8km of coast. La Réserve du Larvotto, in the east of the principality, measures 33.6 hectares and was established in 1975. It shelters some 140,000 square metres of posidonia oceanica, a Mediterranean seagrass that forms meadows below the Monegasque waves at a depth of eight to 25 metres. It also recently became home to a 30-strong community of pinna nobilis – the noble pen shell or giant fan mussel – that was replanted in the protected zone ahead of dredging for the new land extension.

On the western side of the development lies the Tombant des Spélugues, a smaller reserve of 1.9 hectares that was founded in 1986. Despite its close proximity to Port Hercule, the aire marine is populated by numerous types of coral, such as corallium rubrum (also known as precious coral for its uses in jewellery making since Antiquity) and sponges as well as large rockfish. 

“Artificial reefs were laid in Larvotto between 1977 and 1992,” explains Philippe Mondielli, the scientific director of the Fondation Prince Albert II (FPA2). “The most successful for fauna were giant slabs of concrete weighing up to 12 tonnes. There are as many as 600 and were organised into various forms: towers with a central ‘well’ or random piles and labyrinth-type shapes. They were relatively cheap to produce and popular with benthic organisms [starfish, oysters, clams and sea anemones].” Other experiments, such as the Thalamé reefs of 1990, shaped like a turtle’s shell, were better suited to small coastal fish looking for somewhere to escape from conger and moray eels. Rocky blocks deposited at a depth of 30 metres provided reliable – and more natural – surfaces for a whole community of creatures, including algae and shellfish.

“The Larvotto Reserve has ten times the number of animals as the area surrounding it, with a biomass 100 times as big,” says Mondielli. “The protection of the zone, the seagrass and the implantation of artificial reefs have, over the last few decades, brought back a number of emblematic species to our coastline: the brown meagre or corb, the red scorpionfish, gilt-headed bream or dorade royale, and the Mediterranean lobster.” Despite their notable successes, the early attempts in Monaco – and around the world – were built out of concrete and experts now say they were just ‘too simple’ in their design.

“They have been unable to imitate the intricacies of the natural world or adapt to different sites,” says Mondielli.

An idea emerges

During an official visit to the Netherlands in 2014, Prince Albert and the vice-president of his foundation, Bernard Fautrier, attended an event during which Boskalis (a company that manages construction projects and the maintenance of maritime infrastructure around the world) presented a unique concept: 3D printed reefs. “On one hand, Boskalis was looking for a good, 3D printed reef pilot project to increase its knowledge about and experience with the designing, production, placement monitoring, and performance of 3D printed reefs,” says Boskalis engineer Jamie Lescinski, who would later lead the project in Monaco. “On the other, the FPA2 had been looking to create more artificial reefs within Monaco’s waters to continue to improve the ecological health of the Monegasque marine system. Together with the AMPN, the foundation also [saw] this as a unique opportunity to be at the forefront of artificial reef technology and design.”

Boskalis was looking for a good 3D printed reef pilot to increase its knowledge [in the field] and the FPA2 had been looking to create more artificial reefs within Monaco's water to continue to improve the ecological health of the marine system.

Several years earlier, Italian civil engineer Enrico Dini –a pioneer of 3D printing – had met Sydney architect James Gardiner at a conference in Chicago. After introducing Gardiner to his work and experiments with 3D printing, which included designs for aquarium installation, the pair decided to make something for the sea. “James came to stay with me at my facilities in Buti, Pisa, for four months,” says Dini. “He designed the first printed piece I put into the water near Porto Santo Stefano, which was incidentally found and stolen by divers. The next experiment was a 3D printed ring that I observed over several months to monitor the dissolution of the material and the growth of organic matter.”

One of the world's first 3D printed reefs, which was created by Italian civil engineer Enrico Dini, Australian architect James Gardiner and artifical reef pioneer David Lennon for the Reef Arabia projectIn 2012, the duo joined forces with David Lennon of the Reef Design Lab, a leader in advanced and sustainable artificial reef and aquatic habitat design, to create the world’s first 3D printed reef for Reef Arabia in Bahraini waters. Shortly after, Dini was contacted by Boskalis. He would provide the equipment (he gave the international company a printer that had previously been used by the Italian military to build shelters for soldiers) and expertise; Boskalis would provide the commercial power and clout; the AMPN would provide logistical support; and the FPA2 would provide the access. 

3D printing

Developed in the 1980s at the Massachusetts Institute of Technology, the technology of 3D printing was significantly advanced by Dini, known in the tech community as The Man Who Prints Houses for his development of the world’s first 3D printer capable of printing construction-scale structures. The Italian is, however, a very modest man and insists he merely ‘cleaned up the process’.

The Boskalis team printing a reef using Enrico Dini's patented machineToday he is working towards the production of a printer able to create structures up to 36 cubic metres in size. Monaco’s latest artificial reefs were produced using dolomite, volcanic ash and a mysterious binder. Dini says that if a geologist looked at the final product, they would agree it was like solid rock.

“Arriving at the perfect formula was part luck and part mistake,” laughs Dini, who explains that the binder used is ‘basically concentrated seawater’.

The process begins with a 3D object created using a computer-aided design model that is then split into hundreds or even thousands of slices. Dolomite that has been ground into a powdery form is spread out in thin layers of 5mm and the binder is applied to only the exact areas identified in that slice.

“The key aspect of the printing technology is that it enables the reproduction of not only the outer, but also the inner shape of natural reefs,” says a spokesperson for Boskalis. “A scientific study has revealed that the water flow characteristics through the reef contribute greatly to the health of an artificial reef.”

Printing each reef took over 12 hours – not including the amount of time it took to dig out each piece and clear away the aggregate from its interior holes and spaces. “While dolomite isn’t traditionally used for maritime purposes, the calcium magnesium carbonate is essentially the seafloor,” explains Dini. “There’s poetry in returning it to that environment! It gives a very homogeneous finish in a beautiful creamy pink colour, and the pH of dolomite is also ideal for the reefs as it is close to the natural pH of coral. It provides a much friendlier home to species than concrete, which has a basic pH of 13 and can contaminate the organisms that make their home on the reef.”

A reef is craned into position from a boat organised by the AMPN, one of the teams central to the operation. Copyright J M Mille/AMPNTime for immersion

Three years after Prince Albert first heard about Boskalis’ project, the reefs were finally immersed off the coast of Monaco at a depth of 27 metres in November 2017. In total, six large reefs measuring 1.95m in diameter and 1.25m in height (and weighing 2.5 tonnes each) were sunk in a triangle shape, with two at each point, several metres from the reserve’s seagrass fields on the silty seabed. At the centre of the triangle, a mini-vil-lage of reefs a quarter of the size was planted.

“This specific set-up, in a place where there are little natural habitats, will increase the likelihood of colonisation by different species,” explains AMPN’s Gautier-Debernardi, “and allow us to develop an index by which to measure their structural complexity that we can compare with natural habitats.”

As previously mentioned, recent scientific studies have suggested that the increase in the complexity of a structure leads to an increase of biological diversity. “These 3D printed structures are the first step in imagining reefs designed to draw in certain species: the dusky grouper, octopus, langoustine, and juveniles, for example,” continues Gautier-Debernardi. “The reefs feature cavities and holes of different sizes; they are well-adapted for a range of animals.”

Over the next two years, the reefs will be closely monitored by divers and students from the ECOMERS laboratory of the University of Nice, and AMPN will inspect the units on a frequent basis.

Various associations will be keeping a close eye on the reefs and their developments over the next two years. Copyright J M Mille/AMPN“They will be looking at the behaviour of the fish and crustaceans, as well as the colonisation of the reef by taking samples of the biofilm where the growth of algae and bacteria is evident,” explains a spokesperson from Boskalis, which hopes to extend the project if it proves successful. “The results will then be compared with other artificial and natural reefs in the Larvotto Reserve and surrounding research sites.”

Dini too will be keeping a close eye on the Monegasque reefs: “This kind of work is so very interesting and it is huge news for Monaco and the Mediterranean. I have been diving and snorkelling since my childhood and would ever say that seawater is in my blood. In these dangerous times of global warming and depleted fish stocks, I am proud to be fighting for marine populations – building for another form of life is not a matter of business, but a passion borne out of love. You can create almost anything imaginable with 3D printing; it is a beautiful and unique art.”


Elsa Carpenter

*Originally published in the #177 edition of Riviera Insider