Nitrogen (N) deposition associated with acid rain represents a chronic input of reactive N to temperate ecosystems in the Appalachian Mountains. Given N cycling is relatively closed in temperate ecosystems, where inputs and outputs are low compared to internal circulation, N deposition may act as a broad scale environmental driver if systems are sensitive to excess nitrogen. While many studies have examined the influence of acid deposition on terrestrial biogeochemical dynamics, stream acidification and toxic metal mobility, few studies have investigated the effect of N loading on carbon (C) dynamics. To explore the influence of N deposition on C dynamics, we investigated changes in dissolved organic matter (DOM) bioavailability across 18 watersheds in the Appalachian Mountains along an N deposition gradient (5.1 – 32.2 kg N ha-1 yr-1). Further, we addressed how loading influences may vary with location within the watershed-soils, groundwater, and surface water. We found a strong relationship between increased N deposition and decreased DOM bioavailability in compartments (e.g. surface water, r2=.82) along the biogeochemical continuum. Significant decreases in DOM bioavailability also exist along continuums from soil to stream. N deposition appears to be a regional driver of C dynamics, substantially changing DOM bioavailability in local and contiguous systems.