In situ characterization of benthic fluxes and denitrification efficiency in a newly re-established mussel farm

Mussel farming has been proposed as a mechanism to mitigate eutrophication in coastal waters. However, localizing the intensive filtration of organic matter by mussels can cause concomitant enrichment sediments below farms, which may influence biogeochemical processes and fates nutrients system. In context mitigating eutrophication, it is important quantify sedimentary changes induced at early life stages mussel farms. Accordingly, this study investigated how newly re-established farm affected sedimentation rates, sediment characteristics, sediment-water solute fluxes nitrate (NO3?) reduction rates (measured situ) during first year production. Sedimentation were enhanced relative reference station, both inorganic carbon accumulated with time. Increased input likely drove slightly elevated effluxes ammonium (NH4+) dissolved phosphorus (DIP) farm. Denitrification was main NO3? process, however, there increase remobilization bioavailable nitrogen underneath dissimilatory (DNRA) >200% denitrification efficiency 49% lower compared station. The methane (CH4) release tended be higher farm, but not significantly different from conditions. Low pigment concentrations indicated reduced presence benthic microalgae influenced fluxes. Over production cycle, (DIN) DIP respectively 426% 510% Impacts thus measurable already establishment. These immediate biogeochemistry, well long-term effects, should considered when estimating environmental impact aquaculture.