Effects of a commercial, suspended eastern oyster nursery upon nutrient and sediment chemistry in a temperate, coastal embayment

We explored chemical effects of a commercial Floating-Upwelling-System (FLUPSY) stocked with juvenile oysters Crassostrea virginica in a small embayment. Water from the FLUPSY outflow was analyzed for nutrients (total ammonia, nitrate+nitrite, phosphate, and silicate), total suspended material (TSM), chlorophyll (chl) a, and particulate organic carbon and nitrogen (C:N). The output from the FLUPSY was compared to estuarine transects in the Bay to determine if any outputs from the FLUPSY could be detected within the embayment. Sediment samples taken near the FLUPSY and throughout the embayment were analyzed for fluxes of total ammonia, hydrogen sulfide, and oxygen. Dissolved nutrient concentrations in the FLUPSY output were no higher than in the rest of the embayment. There were, however, elevated concentrations of TSM and chl a near the FLUPSY compared to other sites in the embayment. Furthermore, suspended organic matter near the FLUPSY had a C: N ratio near the Redfield ratio, while the rest of the embayment had an elevated C: N ratio indicative of phytoplankton nitrogen limitation. These findings suggest that nutrient recycling by microbes may have been occurring in the vicinity of the FLUPSY. Sediment data showed no difference in fluxes of oxygen, hydrogen sulfide, or total ammonia between the FLUPSY output and elsewhere in the embayment. These findings suggest that the FLUPSY had very minimal effects on the chemical ecology of the embayment.