1. Effects of Acidic Deposition and Calculating Critical Loads of Acidic Deposition in the Adirondack Region of New York By Charles T. Driscoll Syracuse University

2. Outline Data sets Model calculations Critical load calculations Conclusions

4. Collaborators Syracuse University – Wei Wu – Jing Zhai – Richard Warby – Chris Johnson – Brenden McNeil NYDEC/ALSC – Karen Roy SUNY ESF – Myron Mitchell E&S – Tim Sullivan Univ. Virginia – Jack Cosby USDA FS – Linda Pardo – Natasha Duarte

5. Data Sets and Tools Survey – ALSC (chemistry, fish) – EMAP/Time (chemistry) – DDRP (chemistry, soil, foliage) Monitoring – ALTM (chemistry, soil) – RPI (aquatic biota?) GIS – Atmospheric deposition – Vegetation – Land disturbance Models – PnET-BGC (dynamic) – MAGIC (dynamic) – VSD (steady-state)

6. % Less than Ca

11. Climatic data Solar radiation Precipitation Temperature PnET Water balance Photosynthesis Living biomass Litterfall Net Mineralization BGC – Surface water Aqueous reactions Uptake Deep water flow Shallow water flow Weathering Wet Deposition Dry Deposition BGC Aqueous reactions Surface reactions Cation exchange Adsorption Humic binding Aluminum dissolution/precipitation

15. Model simulated median concentrations for lake chemistry and soil % BS at the 44 EMAP sites for pre- industrial and current conditions. Pre-industrial conditions (1850) Current conditions (1990) SO 4 2- (μeq/L)15.988.8 NO 3 - (μeq/L)3.820.0 ANC (μeq/L)67.727.8 pH6.635.95 Soil %BS12.37.9

17. The mean water concentrations from model for the 44 EMAP sites in 2000 and 2100 for three future scenarios. Values are expressed as ueq/L, except pH. 2000 2100 Base Case 2100 Moderate 2100 Aggressive SO 4 2- +NO 3 - 92.379.855.746.0 ANC48.047.862.168.4 pH5.905.866.106.19

20. Very Simple Dynamic Model Atmospheric deposition Net nutrient uptake Rooting Zone Soil leaching Soil weathering Biomass removal N Immobilization N leaching = f(soil C:N) BC Exchange (Gapon or Gaines-Thomas)

22. Conclusions Soils and surface waters in the Adirondacks have been impacted by acidic deposition Databases, data layers and tools are available to facilitate critical load calculations Regional scale applications of PnET-BGC have been conducted to quantify past and potential future response of soil and lakes to changes in acidic deposition Preliminary efforts are underway to investigate critical load calculations in the Adirondacks