This project is rooted in the society’s desire to combat climate change by reducing emissions of CO2. This can be done by using renewable energy sources, one of them being wind. As wind energy developments require considerable space and wind, they are often located in open, windy landscapes, which are widely available at sea, leading to a proliferation of offshore wind farms (OWFs). The wind turbines act as new artificial hard substrates and are rapidly colonised by fouling fauna in high densities, the majority of them (in terms of species, density and biomass) being suspension feeders, feeding on organic material from the water column. At the same time, in the immediate vicinity of turbines, strong changes in sediment characteristics and infauna have been revealed.

These changes encompass a fining and organic enrichment of the sediment, with increased anoxia in otherwise well-aerated sediment, and a shift in macrofaunal communities. These changes have been hypothesised to originate from the biodeposition of organic material, mainly in the form of faecal pellets and pseudofaeces produced by the fouling organisms on the turbines.

The overarching hypothesis of OUTFLOW is that the faecal pellet production by fouling fauna plays an important role in the local organic matter dynamics and carbon sequestration in sediments within offshore wind farms. This hypothesis will be tested through 6 objectives: (1) develop tracers for faecal pellets; (2) estimate the contribution of faecal pellets to the pelagic and sedimentary organic matter pool in OWFs; (3) model the spatial dimensions of enrichment of OWF sediments; (4) determine the fate of faecal pellets in the sediment; (5) estimate the carbon sequestration potential of altered offshore wind farm sediments, and (6) investigate the effect of offshore wind farms on organic matter dynamics and carbon sequestration at a larger geographical scale.