Critical Landscape Interfaces: The Coupled Role of Hydrologic Flowpaths and Biogeochemical Processes in Controlling Solute Fluxes From Forested WatershedsEPA Grant Number: U916154
Title: Critical Landscape Interfaces: The Coupled Role of Hydrologic Flowpaths and Biogeochemical Processes in Controlling Solute Fluxes From Forested Watersheds
Investigators: Sebestyen, Stephen D.
Institution: SUNY Health Science Center at Syracuse
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $86,603
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Ecology and Ecosystems
The objective of this research project is to focus on N (nitrogen) and its associations with dissolved organic carbon (DOC) and water cycles at the Sleepers River Research Watershed, Vermont, to determine: (1) how variations in soil C (carbon) and N pools, N transformations, and flowpath connections can explain N and DOC fluxes in stream water; and (2) how contributions from various N sources (different subbasins of the Sleepers River Research Watershed) contribute to lowland streams and how dominant transformations in subbasins control N loading. Biogeochemical processes control the movement and retention of solutes in watersheds. Notably, water chemistry can be reset by biogeochemical transformations that occur where electron donors and acceptors converge along flowpaths—the "hot spots" in space (e.g., riparian and hyporheic zones) and "hot moments" in time (e.g., during flushing events).
Through synoptic stream surveys and detailed event sampling (rainfall and snowmelt), I will characterize N loads, sources, and transformations that influence N movement from landscapes to streams using new tracing techniques (the isotopes of nitrate, 15N, 17O, and 18O). To characterize the spatial distribution of nutrients across the watershed, I will measure soil C to N ratios and the chemistry of stream, soil, and groundwaters (nutrients, DOC, and cations). Hydrological connectivity of the landscape to the stream will be determined through hydrometrics (water levels in wells, discharge and recharge locations with piezometers, streamflow, and soil moisture) and hydrological modeling (TOPMODEL). With these approaches, I will determine how nutrient sources and biogeochemical transformations link N in the landscape to streams to understand factors that influence the fate and transport of solutes from watersheds.