EU network of mesocosms facilities for research on marine and freshwater ecosystems open for global collaboration.

Study of mesopredator effects in mesocosms.

At the research station Solberstrand (NIVA, Norwegian Institute for Water Research), South Norway, we have over years established 12 similar rocky shore ecosystems with high diversity of seaweeds and macrofauna. Each mesocosm has a volume of about 12 m3, has continuous sea water supply, a wave generator, and tidal regulation. The 12 mesocosms give possibilities to make short and long-term controlled ecosystem manipulation experiments with different and multiple anthropogenic based drivers as pollutions or biological interactions.

Overfishing of top predator fish have resulted in release of mesopredators, in Norway we have observed high densities of wrasses and green crabs. Experiments with these small predators separate and in combination has shown their negative impacts on the ecosystem if they occur in high densities. A recent publication shows their rapid total removal of small mussels and barnacles on stones transplanted into the mesocosms. In mesocosms with both mesopredators present, the removal of mussels was particularly quick although they had plenty alternative food organisms.

Christie H, Kraufvelin P, Kraufvelin L, Niemi N, Rinde E. (2020). Disappearing blue mussels -can mesopredators be blamed? Frontiers in Marine Science, section Marine Ecosystem Ecology. Front. Mar. Sci., 07 July 2020 | https://doi.org/10.3389/fmars.2020.00550