Sulfur, nitrogen, and climate change biogeochemical and empirical effects modeling in the eastern United States: what are we doing and why might anybody care?

T.J. Sullivan1 and T.C. McDonnell2

Recent research has focused attention on the responses of aquatic and terrestrial resources in the eastern United States to decreasing levels of atmospheric nitrogen (N) and sulfur (S) deposition in the context of a changing climate. Both empirical and coupled biogeochemical and ecological response models have proven useful in highlighting uncertainties in data availability and scientific understanding of the major processes that govern chemical and biological responses. Research undertaken recently by our project team is highlighted here, including 1) empirical analysis of the influence of climate on the long-term recovery of Adirondack Mountain lake chemistry from prior high levels of atmospheric S and N deposition; 2) interactions between stream acidification (top-down stressor) and stream warming (bottom-up stressor) as controls on the suitability of stream habitats for cool water species in the southern Appalachian Mountain region; and 3) biogeochemical and terrestrial plant biodiversity modeling at three sites in New Hampshire, Virginia, and Tennessee, using the coupled model chains ForSAFE-Veg and VSD+PROPS. Results of model projections and some of their uncertainties are discussed.

 

1E & S Environmental, tim.sullivan@esenvironmental.com
2E & S Environmental, todd.mcdonnell@esenvironmental.com