3–5 juni: Cold-water corals in Bratten

Deep below the surface in the Skagerrak, in steep underwater canyons and on hard-bottom habitats, cold-water corals form fragile, garden-like communities. In June 2026, researchers from the University of Gothenburg return to Bratten Marine Protected Area with R/V Skagerak to continue their work on some of Sweden’s least-known deep-sea coral ecosystems.

The expedition is led by Professor Rhian Waller and takes place 3–5 June 2026. It follows the research team’s first expedition to Bratten in autumn 2025, when scientists used R/V Skagerak to study cold-water corals in areas with different levels of fishing pressure. That expedition was part of the long-term research project REEFS, funded by the Swedish Environmental Protection Agency.

Returning to Bratten’s coral gardens

Cold-water corals can grow as reefs, gardens and bioherms, creating complex habitats for thousands of associated invertebrates and fish. As ecosystem engineers, they influence local water movement and provide shelter, spawning areas and nursery grounds for marine life.

Unlike tropical corals, cold-water corals do not rely on photosynthetic algae. Instead, they feed on marine snow — particles of organic matter that sink through the water column. They also grow very slowly, often only millimetres per year, which makes them highly vulnerable to disturbance. If damaged, recovery can take decades or even centuries.

The Skagerrak hosts several species of cold-water corals, but only Desmophyllum pertusum has been studied in detail. Less is known about other species, including several octocorals found in Bratten that are listed as threatened by OSPAR and the Swedish Red List.

Why Bratten matters

Bratten is one of the most important marine protected areas in Swedish waters. Designated as a Natura 2000 site in 2011 and an OSPAR Marine Protected Area in 2012, it covers more than 1,200 square kilometres and includes a mosaic of habitats such as pockmarks, canyons, hard-bottom areas and soft sediments.

It is also an important fishing area for Sweden, Norway and Denmark, with species such as shrimp, cod, flounder and halibut. Although Bratten includes several no-take zones, large parts of the area remain open to bottom fishing.

Understanding how cold-water coral ecosystems function in both protected and fished areas is therefore essential for supporting ecosystem-based management.

The research

The main goal of the project is to strengthen knowledge about biodiversity and ecosystem function in Bratten Marine Protected Area.

During the expedition, the research team will investigate the ecological roles of three key cold-water coral species:

Primnoa resedaeformis
Paramuricea placomus
Swiftia sp.

The researchers will compare coral communities in protected areas and areas open to fishing, with the aim of better understanding how these species contribute to the wider ecosystem — and how they may be affected by human activity and environmental change.

In the previous expedition, the team used R/V Skagerak as a platform for work with ROV, plankton sampling and CTD measurements, allowing them to study the coral habitats from the seabed to the water column.