Marine Ecosystem Renewal

Zaha Hadid Architects’ Nereid is a 3d-printed concrete structure designed to restore Hong Kong’s marine ecosystem by creating the perfect environment for organisms to thrive.

The white dolphins are leaving the waters around Hong Kong, and the reasons are all too predictable: overfishing, pollution and excess surface vessel traffic. “These problems have combined to degrade the marine environment, particularly the seabed, to the point where it is no longer able to support the numbers of fish the dolphins need,” says Christos Passas, design director with Zaha Hadid Architects. “So we have looked at how we can use good design to help restore the seabed, and make it more conducive to sea life.”

The result is Nereid, a 3D-printed concrete structure. When placed on the seabed, it will provide an optimal environment for the growth of phytoplankton and shellfish – the foundation of the marine ecosystem’s food chain. A 1m-high prototype, constructed by Hong Kong firm D-shape, was exhibited at this year’s World Design Congress (WDC) in London.

“Using 3D-printed concrete provides a number of useful features,” says Passas. “We can create an object with a rough, naturalistic surface that suits the plants and animals that will attach themselves to it. We can also easily mimic the features of natural reefs – for example, by making hollows in the structures where fish can safely lay eggs or hide from predators.”

Almost any object left on the seabed will eventually attract sea life of some sort: “But Nereid gives us the opportunity to intervene in a very specific way. For example, by providing safe hiding spaces of the right size, and at the right depth for a particular species.”

Using printed concrete makes it relatively easy to adapt the design to respond to other challenges: “We can adjust the base so Nereid does not sink too far into a soft sea bed, or we can adjust the strength and weight to discourage trawlers, which can cause damage by scraping nets along the seabed.”

It also offers logistical advantages: while solid concrete forms are very heavy, Nereid’s outer shell is only around 20mm thick. “Larger forms can therefore be much lighter, and easier and cheaper to transport to where they are needed,” says Passas. “And of course, non-solid structures can be much more efficient in terms of material usage.”

The mix used to create Nereid has been carefully designed to be eco-friendly. D-shape deploys an unusual technology which, instead of printing pre-mixed concrete, lays down a layer of sand and cement before jetting it with pure water. “There are minimal additional binders or other chemicals involved – obviously a benefit when you are trying to restore a natural ecosystem.” The mix is resilient to the chloride in seawater and also pH neutral: “Sea life prefers surfaces that are not too acid or alkaline.”

Though Nereid was developed with the waters around Hong Kong in mind, Passas says it could be fine-tuned to suit other locations and ecosystems. “There could be a variety of applications,” he says. “For example, there’s an underwater sculpture park off the shores of Cyprus. It is like a civic plaza, with statues of people on phones and of children playing. It is a great draw for recreational divers. With the flexibility 3D-printing gives us, you can easily imagine how Nereid-type structures could help create environments like that. They could be beautifully sculpted, and help marine life at the same time.”

Nereid is well-named – after the sea nymphs of ancient Greece who were charged with protecting the oceans and the life they contained. If all goes to plan, Zaha Hadid’s concrete Nereids could soon be luring the white dolphins back to the seas around Hong Kong. 

Interview by Tony Whitehead

Photos Luke Hayes