Offshore wind farms (OWFs) introduce artificial hard-substrates into generally soft-bottom environments and are rapidly colonized by suspension feeders. The new biomass attracts fish and top predators and enriches macrobenthos in the surrounding area. However, these changes are dynamic, evolving over time through shifts in community composition and dominance. Using a unique 14-year dataset (2009-2023) from the C-Power OWF (Belgium), spanning both early colonization and mature operational stages of OWF development, we present the first long-term, data-driven assessment of OWF impacts on the marine food web and its carbon flows. By combining qualitative and quantitative food web (Linear Inverse Model) modelling approaches, we demonstrate that OWF development enhances carbon flow through the system and reshapes how energy is distributed among trophic pathways. A shift towards a suspension-feeding-dominated community lowers connectance, trophic level, and omnivory, thereby reducing trophic flexibility. Over time, a greater number of hard-substrate organisms emerge as module connectors, decreasing overall modularity and facilitating the spread of potential perturbations. Overall secondary production does not show increasing trends with time. Our findings suggest that OWF development alters the marine food web in a dynamic process that evolves through time, with several food web indices pointing towards a potential reduction in ecosystem stability over time. Our insights emphasize the value of using food web indices for monitoring ecosystem functioning under anthropogenic pressures. |
