Impacts of long-line aquaculture of Pacific oysters (Crassostrea gigas) on sulfate reduction and diffusive nutrient flux in the coastal sediments of Jinhae–Tongyeong, Korea

We investigated the environmental impacts of long-line aquaculture of Pacific oysters (Crassostrea gigas) on sediment geochemistry and carbon oxidation by sulfate reduction and diffusive benthic nutrient flux in a coastal ecosystem in Korea. Inventories of the NH 4 + and HPO 4 2 - at the farm site were 7.7–11.5 and 1.8–8.0 times higher, respectively, than those at a reference site. Sulfate reduction rates (SRRs) at the oyster farm were 2.4–5.2 times higher than SRRs at the reference site. The SRRs at the farm site were responsible for 48–99% (average 70%) of the total C oxidation in the sediment. The diffusive benthic fluxes of NH 4 + and HPO 4 2 - at the oyster farm were comparable to 30–164% and 19–58%, respectively, of the N and P demands for primary production, and were responsible for the enhanced benthic microalgal biomass on the surface sediment.