<p>Seep ecosystems connected to subseafloor methane reservoirs are widespread in the Arctic due to factors such as organic material accumulation and an extensive gas hydrate stability zone. Recently, submarine groundwater discharge (SGD) stemming from past glaciation has been identified as an additional factor that can generate Arctic seep systems. Despite seeps having an extended ‘sphere of influence’, links to the surrounding seafloor have not been studied in the Arctic, which is why we investigated the epifaunal megabenthos at the edges of an SGD-derived Arctic seep off northern Norway. Due to local, chemosynthesis-based food production and substrate heterogeneity, Arctic seeps are often local biodiversity hotspots. However, our study revealed that communities at the peripheries of the seep (transition zone/ecotone or ‘chemotone’) are an order of magnitude more diverse and species rich than inside the seep itself. Neither seep nor chemotone contain specialist fauna, and benthic species appear to aggregate differently at Arctic seeps, their peripheries and background, despite not being specifically adapted for any one of the habitats. Through stable isotope analyses, we detected chemosynthetically derived carbon in peripheral animals, suggesting that export beyond the seep is possible. Suspension feeders were numerous and diverse in the chemotone (e.g. thousands of individuals of colonial anemones) as well as in non-seep canyons in the region which brings forth the question of whether high latitude seeps benefit or promote these feeding styles overall as opposed to specific organisms such as corals. The cryosphere of both the past and present can generate seeps which can impact trophic dynamics and species composition well beyond their own boundaries.</p>