Two offshore wind farms became functional in the Belgian part of the North Sea during 2009 and 2010 on respectively the Thorntonbank (C-Power) and the Bligh Bank (Belwind). Since 2005, a monitoring programme has been carried out to determine the baseline situation on the soft-sediment macrobenthos in these areas, together with any primary impacts that could have arisen during and after construction. During the first and second years after implementation of the turbines no large-scale impacts were detected on the macrobenthos. Therefore, a small scale sampling strategy was carried out from 2010 until 2012 to detect any impacts around the fifth gravity based turbine on the Thorntonbank. Macrobenthic communities can be highly dependent of sedimentological characteristics such as median grain size and organic matter content. The increased epifaunal communities colonizing the hard substrates (turbines) could produce organic enriched sediments, possibly modifying the soft-sediment macrobenthic communities. Any impact detected at small-scale can be extrapolated to a possible large-scale impact. Since future plans have been made to construct additional wind farms in the Belgian part of the North Sea it is very important to understand the possible changes that could occur in the marine environment.
