3D-Printed Artificial Reefs Revive Marine Life in Danish Ports

Introduction

In early September 2025, Danish port authorities launched an environmental initiative aimed at reviving marine ecosystems inside harbors. The plan involves installing 3D-printed artificial reef units along submerged quay walls, responding to decades of biodiversity loss and encouraging the return of fish and other organisms once common in these waters.

Installation of 3D-printed reef modules on a quay wall at Helsingør Port — Workers install 3D-printed artificial reef modules to enhance marine biodiversity at Helsingør Port.

Technology and Materials

Each unit is produced with low-carbon concrete, blended local aggregates, and crushed mussel shells to create a rough texture that helps marine larvae attach and grow.
The design imitates natural reefs through small cavities and perforations, offering safe micro-habitats and supporting the early stages of an aquatic food chain.

Implementation Sites

Aarhus Port
Korsør Port
Helsingør Port
Sprogø Port
Fredericia Port

Growth of algae and small fish on 3D-printed reef modules — The image shows marine life returning to the 3D-printed reef modules a few months after installation.

On 20 August 2025, the Port of Copenhagen also began installing its first reef units as part of a wider rollout.

Early Results

Algae and mussels appeared within just a few months of installation.
Small fish soon followed, and later larger species such as cod and eel, particularly in Fredericia.
The structures provide natural shelter, helping restore ecological balance without disrupting port operations.

Project Partners

Stonereefs – lead developer and designer of the reef modules
Cobod – 3D printing specialist supplying the BOD2 printer
Universities and students – contributing new design concepts and monitoring reef colonization through live camera feeds

Installation of 3D-printed reef units at Fredericia Port — Workers install 3D-printed reef modules at Fredericia Port to support local marine biodiversity.

Statement

Mikkel Brich, founder of Stonereefs, noted:

“3D printing allows us to enhance biodiversity without interfering with daily port activities. Once you give nature a foothold, life returns within months.”

✦ ArchUp Editorial Insight

This project demonstrates the use of 3D-printed artificial reef units to restore marine life in Danish ports, employing low-carbon concrete and local mussel shells to provide surfaces suitable for larvae settlement. The design includes fine cavities that mimic natural reefs, fostering rapid colonization by fish and algae. Yet, while the initial outcomes are promising, questions remain regarding the long-term sustainability of the units and their integration with the local ecosystem. Nonetheless, the project provides a practical example of innovative sustainable design strategies applicable to future marine environments.

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