In situmacrofaunal respiration rates and their importance for benthic carbon mineralization on the northwestern Black Sea shelf

Abstract

Abstract Benthic fauna assemblages and organic carbon mineralization processes were studied in the northwestern Black Sea along a transect from the well-oxygenated shelf to the (deep) anoxic basin. Bivalves dominated the coenoses at the three oxygenated stations, but with decreasing macrofaunal biomass at increasing water depth. The previously well-described zonation of macrofaunal communities for the northwestern shelf of the Black Sea was also found in this study (Mytilus galloprovincialis coenosis at Station 1 (62 m), Modiolus phaseolinus coenosis at Station 2 (77 m) and 3 (100 m)). The highest meiofauna density was found at the transition from oxic to anoxic bottom waters (Station 4, 130 m, < 5 μM O2). Reduced predation and sufficient food supply are suggested to be of importance at that site. The weight-specific fauna-mediated respiration rate of the mussel community was independent of water depth and always around 14 nmol O2 mg ww-1 d-1. Thus indicating that the mussel communities on the northwester...