Loss of macrofaunal bioturbation and bioirrigation activity may strongly reduce benthic biogeochemical cycling and thus ecosystem functioning. The identification of bioturbating key species in the marine benthic realm is therefore of high importance for ecosystem management purposes. In this study top bioturbators in the German Bight were identified by mapping the trait based bioturbation potential (BPc) for 423 North Sea stations. BPc mapping highlighted the importance of Amphiura filiformis, Echinocardium cordatum and Nucula nitidosa as major bioturbating species in the German Bight. Effects of their bioturbation and bioirrigation activity on silicate, ammonium and nitrate flux were investigated in laboratory experiments. While E. cordatum significantly influenced biogeochemical cycling, effects of A. filiformis remained inconclusive probably due to arm regeneration. N. nitidosa showed little impact on biogeochemical cycling, although the bivalve was found to be an important bioturbator. E. cordatum may thus be considered an essential mediator of biogeochemical cycling in the sediment water interface as well as one of the most important bioturbators in the German Bight.