EFFECTS OF SUSPENDED MUSSEL CULTURE (MYTILUS SPP) ON SEDIMENTATION, BENTHIC RESPIRATION AND SEDIMENT NUTRIENT DYNAMICS IN A COASTAL BAY

Many studies have shown that the primary effect of shellfish culture o n nearshore marine systems is enhanced sedimentation. This study was d esigned to measure the effects of this enhanced sedimentation on the r espiration and nutrient fluxes of the benthic community and the coupli ng between the pelagic and benthic systems at a mussel culture site (M ytilus edulis and M. trossulus) in Upper South Cove, Nova Scotia, Cana da. There was a significant association between chlorophyll in the wat er column and sedimentation rate in Upper South Cove over the study ye ar, 1990, particularly under the mussel lines, but the majority of the particulate carbon and nitrogen which fell to the bottom was not inco rporated into the sediments. Suspended mussel culture had little impac t on sediment phosphorus dynamics. The largest response of the sedimen t community to suspended mussel culture was ammonium release, which wa s higher under the mussel lines at all times of the year. Over the yea r, the sediments of the reference site were a net sink for total disso lved nitrogen, while the sediments under the mussel line were a source .