This research represents a multi-disciplinary and multi-institutional effort to extrapolate research, monitoring, and modeling results, including physical, chemical, and biological findings from intensively-studied lakes to the regional population of acid-sensitive Adirondack lakes. A total of 70 watersheds were included in this effort, which involved field sampling to develop a statistically-representative soils database and model projections using the MAGIC and PnET-BGC models to classify lakes according to their sensitivity to change in atmospheric sulfur (S) and nitrogen (N) deposition. Results of this research will allow fuller utilization of data from on-going chemical and biological monitoring and process-level studies. A mechanism is provided for regionalization of findings. This approach was accomplished by developing/refining relationships among watershed characteristics, chemical change, and biological responses to changing levels of acid deposition. Such information is important for the management of the ecosystems in New York that are most responsive to changes in acid deposition. Project completion was November 2006.