Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901-2008

Abstract

We used a process-based land model, Dynamic Land Ecosystem Model 2.0, to examine how climatic and anthropogenic changes affected riverine fluxes of ammonium (NH ), nitrate (NO ), dissolved organic nitrogen (DON), and particulate organic nitrogen (PON) from eastern North America, especially the drainage areas of the Gulf of Maine (GOM), Mid-Atlantic Bight (MAB), and South Atlantic Bight (SAB) during 1901-2008. Model simulations indicated that annual fluxes of NH , NO , DON, and PON from the study area during 1980-2008 were 0.019 ± 0.003 (mean ± 1 standard deviation) Tg N yr , 0.18 ± 0.035 Tg N yr , 0.10 ± 0.016 Tg N yr , and 0.043 ± 0.008 Tg N yr , respectively. NH , NO , and DON exports incr..