Rebuilding the Arctic Seafloor: Elnida-rif® Reefs in the Porsangerfjord, Norway

• September 24, 2025

In the far north of Norway, deep inside the Porsangerfjord, an ambitious marine restoration effort has taken shape. On August 29, 2025, 30 Elnida-rif® reef units were placed on the seafloor. Developed by Underwater Gardens International (UGI) in close collaboration with Norway’s Institute for Marine Research (IMR), the project forms part of OCEAN CITIZEN.

These reefs are more than artificial platforms. They are purpose-built habitats designed to respond to two pressing challenges: creating safe refuge for young Atlantic cod (Gadus morhua) and encouraging healthy kelp forests to return. Kelp such as Saccharina latissima, Alaria esculenta, and Laminaria species play a central role in biodiversity and maintaining balance in Arctic waters.

Blending science with design

The reefs were arranged in an organic pattern, forming an underwater constellation of structures. This design offers more surface area for algae, kelp, and invertebrates to colonize, while also improving connectivity between habitats – an important factor for building a stronger, more diverse ecosystem.

The work was carried out in late summer, a moment carefully chosen to coincide with kelp reproduction. As spores drift through the water at this time of year, they seek new surfaces to settle on. By spring, the hope is that lush kelp forests will be thriving once again, providing food and shelter for countless smaller organisms.

Why it matters now

The Arctic is warming at an unprecedented pace, and with that comes added pressure from overfishing and habitat loss. Together, these forces have dramatically reduced both cod numbers and kelp coverage. Their decline is not only an ecological concern but a cultural and economic one too—cod fisheries have sustained local communities in northern Norway for centuries.

What the reefs bring to the ecosystem

The Elnida-rif® reefs are expected to generate multiple ecological benefits:

• Higher survival rates for juvenile cod, essential both for marine food webs and fisheries.
• Restoration of kelp habitats, which support biodiversity and absorb carbon.
• Increased habitat complexity, providing room for invertebrates, microorganisms, and other marine life to thrive.
• A working model of restoration that could be adapted to other marine environments, within and beyond the Arctic.

Alongside their installation, the project is backed by a scientific monitoring system. Researchers will track biodiversity levels, kelp development, and the abundance of young cod, enabling them to assess outcomes in real time.

A living laboratory in the Arctic

With these reefs in place, the Porsangerfjord becomes an open-air laboratory for marine recovery. Scientists from IMR and the OCEAN CITIZEN network will be able to follow species colonization, shifts in biodiversity, and ecosystem changes as they happen. The lessons gathered here could inform restoration strategies in other corners of the world.

Collaboration across borders

This initiative stands as an example of what can happen when science, technology, and international cooperation come together. UGI contributes expertise in marine restoration design, IMR guides with local knowledge, and OCEAN CITIZEN unites research institutions across countries. The shared goal is not only conservation but the rebuilding of ecosystems long diminished by human and environmental pressures.

Seeds of renewal under Arctic waters

The reefs in Porsangerfjord are more than concrete or steel structures on the seafloor—they are starting points for renewal. As fish, algae, and kelp establish themselves, they give life back to the waters. Quietly and steadily, they remind us that regeneration is not just an idea, but something already happening in the depths of the Arctic.

More information: https://oceancitizen.eu/news/rebuilding-the-arctic-seafloor-elnida-rif-reefs-in-the-porsangerfjord-norway/