A set of experiments was performed to test 1) how various physicochemical perturbations (salinity, zinc, temperature, soil moisture, and pH) influenced denitrification and nitrous oxide production on short timescales (<1 day) in agricultural soils from Lancaster, PA, USA 2) how variation in a single parameter (salinity) influenced rates of denitrification and nitrous oxide production in sediments that experience a range in that parameter (tidal freshwater, oligohaline, and mesohaline estuarine sediments from the Scheldt River estuary Belgium/Netherlands) on short timescales (< 1 day), and 3) how denitrification and nitrous oxide production along with key functional gene expression in tidal freshwater estuarine soils from the Delaware River, NJ, USA responded to a long-term (6 month) change in a single parameter (salinity) in a press experiment with subsequent short-term (< 1 day) pulses. In the final long-term experiment, nitrite reductase (nirS) and nitrous oxide reductase (nosZ) gene expression was measured at three timepoints (days 7, 35, and 110).