Offshore wind farms can enhance the structural composition and functional dynamics of coastal waters

Offshore wind farms (OWF) are rapidly emerging as essential infrastructure for transitioning to renewable energy, and this has been particularly important in the waters of China. To evaluate the impact of OWF construction, Ecopath models were developed for an OWF area and, separately, for a nearby control area, using biological and environmental survey data collected in 2022 and 2023. Functional groups were initially categorized into soft-substrate and hard-substrate (turbine monopiles) communities. The results showed that the colonization of turbine monopiles by sessile organisms significantly increased the productivity of most fish functional groups in the OWF area compared to the control. The OWF ecosystem exhibited higher trophic levels, especially for macroinvertebrates and fish, and a more complex food web with enhanced detritus flow than the control area. Mixed trophic impact analysis indicated a shift from a pelagic to a benthic-dominated system following OWF construction. Notably, detritus accounted for 52% of total system throughput in the OWF area, compared to 38% in the control area, highlighting a transition toward detritus-based energy flow. Furthermore, the OWF system showed significantly higher values for total system throughput, omnivory index, connectivity, Finn’s cycling index, and ascendency. Overall, the presence of the OWF resulted in significant changes in the trophic flow and system structure, creating a more complex, mature, and stable benthic-dominated ecosystem. These findings indicate that the establishment of OWF enhances both the structural composition and functional dynamics of surrounding marine ecosystems. • Ecopath models for offshore windfarm and control ecosystems were developed. • 27 functional groups including soft- and hard-substrate (turbine monopiles) communities. • Windfarm was dominated by benthic species and a more complex food web than Control. • Windfarm had enhanced detrital flow, higher maturity and greater stability.