Impact of suspended mussel aquaculture on benthic oxygen fluxes and metabolism

Abstract

Suspension cultures of mussels generate large amount of highly labile faeces that alters the benthic-pelagic coupling. This study quantifies the impact of an extensive mussel aquaculture located in the NW Iberian coastal upwelling system on benthic oxygen fluxes and metabolism. Two aquatic eddy covariance (AEC) systems were deployed concurrently, one below a mussel raft and one at a reference site during the summer upwelling season. The sites were 3 km apart, located in the aphotic zone, and exposed to comparable bottom currents. The intense oxygen consumption found below the mussel raft (48 mmol m-2 d-1) was 2.4 times larger than at a reference site. These results were consistent with the higher biodeposition below the mussel raft observed in previous studies, and emphasize the impact mussel aquaculture can have on the benthic-pelagic coupling