What is the status of biocolonization on the FloatGen wind turbine float? How does this biocolonization influence the underlying natural bottom, via the flux of organic matter?
This is what we will try to examine closely and quantify, for 3 years, on the scale of the only floating wind turbine prototype that currently exists in France, the FloatGen demonstrator, installed off the coast of Croisic.
Like any other submerged object at sea, offshore wind turbine foundations are quickly colonized by a variety of algal and benthic invertebrate species, including many filter feeders (up to several kilos per square meter!), but also non-indigenous species (which would not normally be found there).
The influence of offshore wind turbines, especially floating wind turbines, on benthic biodiversity does not end there. The surrounding natural bottoms can be locally impacted by the anchor lines, and can be influenced by the biocolonization (biofouling) present on the wind turbine float. Indeed, many mollusks (especially mussels), worms and crustaceans filter phytoplankton and particles from the sea water to feed and release feces in greater or lesser quantities depending on the species or the season. All this organic and inorganic matter (empty shells, animal corpses) can modify the nature of the benthic habitats and the diversity of the communities underneath.
Antoine Carlier (LEBCO), Nicolas Desroy (LER-BN)