U.S. EPA LTM/TIME
The Environmental Protection Agency’s Regionalized Long-Term Monitoring (RLTM), Temporally Integrated Monitoring of Ecosystems (TIME), and High Elevation Lakes (HELM) projects began prior to implementation of the U.S. Clean Air Act Amendments. The projects documented first the effects of acidic deposition and then changes in geochemistry as acidic inputs have declined. The 30 years of long-term data support U.S. EPA acid rain assessments. Newly-funded UMaine research is using data from these lakes to assess the effects of extreme events on surface waters and changes in dissolved organic carbon through time. Long-term funding has been through U.S. EPA and USGS; HELM and ALPS projects also received funding from the Maine Department of Environmental Protection. University of New Hampshire professor William McDowell is the lead PI; the UMaine lead PI is Sarah Nelson, with Co-PI Jasmine Saros.
- Accelerated Recovery of Maine Lakes (6/2014)
- Mitchell Center Researcher Completes EPA Report Compiling 30 Years of Lake Sampling
- Strock, K., S. Nelson, J. Kahl, J. Saros, W. McDowell, 2014. Decadal trends reveal recent acceleration in the rate of recovery from acidification in the northeastern US. Environ. Sci. Technol. 48(9):4681-4689.
- Sanclements, M., G. Oelsner, D. McKnight, S.J. Nelson, J. Stoddard, 2012. New insights into the source of decadal increases of dissolved organic matter (DOM) in acid-sensitive lakes of the northeastern U.S. Environmental Science and Technology, DOI: 10.1007/s11356-009-0176-7
Bear Brook Watershed in Maine
The Mitchell Center has been involved in research at a pair of instrumented watersheds at Bear Brook Watershed in Maine (BBWM) for a number of years. BBWM is a whole ecosystem manipulation experiment that has been underway since 1987. It encompasses two contiguous 25-acre forested watersheds. Ammonium sulfate fertilizer (surrogate ‘acid rain’) has been applied by helicopter to the experimental watershed since 1989. The adjacent watershed is used as an untreated reference. The BBWM response provides a major evaluation of watershed models used by federal agencies to generate predictions of environmental response to emission control scenarios. UMaine professor Ivan Fernandez is the lead PI; Mitchell Center assistant research professor Sarah Nelson is one of the investigators on the BBWM project.