Nitrogen and Carbon Quality
Thin discs in action.
Denitrification has also been shown to be directly related to total organic carbon concentration across wetland types and engineered marshes typically have less stored carbon than mature marshes with more labile carbon and less recalcitrant carbon. Because constructed salt marshes likely have a lower pool of recalcitrant carbon available to fungal communities than older natural marshes which have had more time to accumulate organic matter, these created sites may not support fully-functioning microbial communities which rely on carbon as a substrate for a variety of heterotrophic processes like denitrification. My thesis research explores carbon quality differences as a potential factor in the loss of nitrogen removal capacity in constructed salt marsh sediment. By adapting thin sediment disc incubations used in estuarine and marine research to terrestrial wetlands, we can efficiently measure nutrient kinetics in mesocosms under different carbon and nitrogen addition regimes.