3D-printed bio-reefs: How printed concrete helps the Baltic Sea
- thomasliebhardt
- Sep 12
- 3 min read
Coming soon – this is what you can expect in this blog post:
PERI 3D Construction puts concrete underwater – for species protection.
Joint pilot project with Holcim, the Fraunhofer Institute and the city of Kiel
Printed reef structures create new habitats for marine life.
3D-printed “fish hotels” strengthen endangered fish species such as cod.
Why does the Baltic Sea need artificial reefs?
The seabed in the Kiel Fjord is under significant pressure: The construction of a barrier-free ferry terminal in Friedrichsort required the removal of old World War II munitions. To do so, large areas of the seabed had to be dredged and cleared — with serious consequences for the local marine habitats.
The solution: artificial reef structures made of concrete – strategically placed as a compensatory measure.
How 3D construction printing helps protect the oceans
Unlike conventional embankments, this project's artificial reefs are made of precisely formed concrete elements. They use a specially developed, climate-friendly concrete that is not only durable but also resource-efficient. A central element of the reef system are three individually designed fish hotels, specifically tailored to the needs of different animal species.
The advantages of this method are obvious: The targeted shaping creates diverse surface structures and cavities that provide ideal habitats for a wide variety of organisms. Algae, mussels, barnacles, and other marine animals find optimal conditions here for permanent settlement. The solid construction also ensures stable anchoring to the seabed – making the structures not only durable but also particularly ecologically effective.
Particular attention is paid to the protection of cod. The printed fish hotels were designed to precisely meet the needs of this endangered fish species—with protected refuges and suitable spawning grounds.
Underwater 3D printing: precision for nature
The printing was done using the proven PERI 3D printing technology, this time not for houses, but for the sea.
Special requirement:
Structural diversity for the settlement of marine organisms
Longevity underwater
Resource-saving production with CO₂-reduced concrete
The bio-reefs were precisely positioned underwater on site by specialists, with the help of professional divers and hydraulic engineers.
The result: a 24 m² reef with carefully placed structures for maximum effect.
Promote biodiversity – improve water quality
What at first glance appears merely as gray concrete quickly transforms underwater into a vibrant ecosystem. After just a short time, mussels and algae begin to colonize the rough surfaces of the printed structures. These organisms perform important functions in the natural cycle – for example, mussel colonies filter up to 200 liters of water per hour, thus contributing to improving water quality.
In addition, the diverse structures create new microhabitats in which fish, crustaceans, and aquatic plants can settle. Cod, in particular, whose populations in the Baltic Sea have declined sharply, finds urgently needed refuges and spawning grounds here. Thus, the artificial reefs not only provide protection but also make an active contribution to the regeneration of marine biodiversity. The first marine life is expected to arrive in just a few weeks – and within about 18 months, a completely new underwater landscape is expected to be established.
Sustainable construction meets environmental protection
This project impressively demonstrates how modern construction technologies and environmental commitment can be combined:
3D printing = precise, resource-saving, scalable
Concrete = durable, versatile, moldable for any environment
PERI 3D Construction + Holcim = innovative partnership for marine conservation
Through targeted planning, intelligent design and automated production, we work together to create solutions that are both ecologically and economically viable.
Conclusion: 3D concrete printing as a key technology for biodiversity
Whether on the construction site or underwater, 3D construction printing is changing the way we build – and how we interact with nature.
With the first printed bio-reef in the Baltic Sea, a new chapter in environmentally conscious construction was opened:
New habitat for endangered species
Clear sign of sustainable innovation
Pilot project with future prospects
Printed by PERI 3D Construction. Developed with Holcim. Placed in the Baltic Sea.
Learn more about 3D concrete printing now
PERI 3D Construction focuses on innovation – above and below water. Whether it's residential construction, infrastructure, or environmental protection: With our 3D printing technology, we offer solutions that inspire lasting impact.
Find out more now & build with us for the future:
