The importance of sandbanks and mussel reefs in the marine ecosystems

More than 30 years after the EU Habitats Directive was adopted, numerous marine habitats and species still fail to meet conservation goals. This is especially evident in Northern Europe, where the marine habitats in the Kattegat-Skagerrak region continue to exhibit poor conservation status.

A new Horizon Europe project, MARHAB, aims at addressing the pressing conservation issues.

As part of this initiative, DTU Aqua takes the lead of a work package focusing on the roles of sandbanks and mussel reefs in marine ecosystems. 

"Diving into the intricacies of these habitats not only fascinates us but is also really important to formulating robust conservation strategies. It's about piecing together a larger ecological puzzle, where each habitat's function and service play a critical role in the overall health of our oceans,” says Associate Professor, DTU Aqua, Mikael van Deurs who is leading the MARHAB work package.

Unravelling the Habitat Puzzle: The Critical Role of Sandbanks

While much attention has often focused on habitat-forming biogenic reefs, such as those formed by mussels, Mikael van Deurs highlights the critical but often overlooked significance of gravel- and sandbanks within marine ecosystems:

"Gravel- and Sand-banks are not just underwater barren landscapes. They are bustling ecosystems housing a myriad of infaunal life, which is animals that live buried in the seabed. Sandy bottoms also serve as essential substrate for seagrass and act as crucial nurseries and essential habitats for a diverse range of fish species, including flatfish and sandeels,” says Mikael van Deurs and underlines the necessity for a deeper exploration and protection of these vital habitats:

“Given their ecological importance, these habitats deserve heightened attention and conservation efforts to ensure the health and resilience of our marine environments.”

Achieving healthy and rich marine habitats

MARHAB, for marine habitats, was kicked off in Norway in February, with participation from all MARHAB-partners, The European Research Executive Agency, European Commission Directorate-General for the Environment, and representatives of MARHAB’s scientific advisory board. 
In response to the ongoing conservation challenges, the international team of researchers join forces in MARHAB to explore ways of achieving healthy and rich marine habitats to sustain the ocean´s ecosystems. 

Their work will focus on the Kattegat and Skagerrak region, aiming to identify and propose effective conservation measures to reverse the current trends.

Even Moland, principal researcher at the Institute of Marine Research (IMR), is leading MARHAB, and he points out the complex relationship between the state of marine habitats and fishing activities as some of the central themes in MARHAB: 
“The status of marine habitats in Europe and elsewhere is tightly linked to fisheries, both via the direct physical impact of fishing – for example caused by bottom trawling, but importantly also via indirect effects of fisheries,” says Even Moland.

Bridging Borders for Ocean Conservation

The roots of the collaboration behind MARHAB can be traced back to a recent and smaller project called SamSkag funded by the Nordic Council of Ministers. 

SamSkag was a smaller-scale initiative that laid the groundwork for this broader, international cooperation.

This new venture represents an exhilarating opportunity to bridge expertise across borders, bringing together a diverse array of science advisors, researchers, and institutions.

Adding to the project's dynamic, Ole Henriksen, a young scientist recently employed as a full-time researcher at DTU Aqua, emphasizes the unique aspect of this collaboration.

"It's not that common to see such a comprehensive assembly of Scandinavian expertise across research fields focused on a shared marine region. This project not only highlights the importance of regional cooperation but also sets a precedent for future endeavours in marine conservation," states Ole Henriksen.

Thus, Ole Henriksen highlights the project's potential to foster a deeper understanding and more effective management of the shared marine resources in the Scandinavian waters.
MARHAB runs for four years from 2024 to the end of 2027.

Illustration:
Mosaic by Mikael van Deurs and Thomas Warnar
Group picture from the kick-off meeting with partners of MARHAB standing on the highest point of the island of Lyngør, Norway