HR: 1340h
AN: H53A-0958    [Abstracts]
TI: A role for high frequency hydrochemical sampling in long term ecosystem studies
AU: * Sebestyen, S D
EM: ssebestyen@fs.fed.us
AF: USDA Forest Service, Northern Research Station 1831 Highway 169 East, Grand Rapids, MN 55744-3399, United States
AU: Shanley, J B
EM: jshanley@usgs.gov
AF: US Geological Survey, 87 State St Room 324, Montpelier, VT 05602, United States
AU: Boyer, E W
EM: boyer@nature.berkeley.edu
AF: University of California, Mulford Hall 3114, Berkeley, CA 94720-3114, United States
AU: Kendall, C
EM: ckendall@usgs.gov
AF: US Geological Survey, 345 Middlefield Road, Menlo Park, CA 94025, United States
AB: Monitoring of surface waters for major chemical constituents is needed to assess long-term trends and responses to ecological disturbance. However, the typical fixed-interval (weekly, monthly, or quarterly) sampling schemes of most long-term ecosystem studies may not capture the full range of stream chemical variation and do not always provide enough information to discern the landscape processes that control surface water chemistry and solute loadings. To expand upon traditional hydrochemical monitoring, we collected high frequency event-based surface water samples at an upland, forested basin of the Sleepers River Research Watershed (Vermont, USA), one of five intensively studied sites in the Water, Energy, and Biogeochemical Budgets (WEBB) program of the US Geological Survey. We present several examples that highlight the importance of linking long-term weekly data with intensive, high frequency sampling. We used end-member mixing analysis and isotopic approaches to trace sources of stream nutrients (e.g. nitrate, dissolved organic carbon) and quantified how atmospheric pollutants (e.g. nitrogen, sulfate, and mercury) affect stream chemistry. High frequency sampling generates large numbers of samples and is both labor and resource intensive but yields insights into ecosystem functions that are not readily discerned from less-frequent sampling. As the ecological community contemplates the scope and foci of environmental observatories as benchmarks for deciphering the effects of natural and anthropogenic change, incorporating high frequency hydrochemical sampling will further our understanding of ecosystem functions across a range of ecosystem types and disturbance effects.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 1804 Catchment
DE: 1806 Chemistry of fresh water
DE: 1860 Streamflow
SC: Hydrology [H]
MN: 2007 Fall Meeting