Grantee Research Project Results

Critical Landscape Interfaces: The Coupled Role of Hydrologic Flowpaths and Biogeochemical Processes in Controlling Solute Fluxes From Forested Watersheds

EPA 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: The State University of New York
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2003 through January 1, 2006
Project Amount: $86,603
RFA: STAR Graduate Fellowships (2003) Recipients Lists
Research Category: Academic Fellowships , Fellowship - Aquatic Ecology and Ecosystems

Objective:

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).

Approach:

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, delta ¹⁵N, delta ¹⁷O, and delta 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.

Supplemental Keywords:

fellowship, biogeochemical processes, hydrologic flow paths, solute fluxes, forested watersheds, nitrogen, N, carbon, C, dissolved organic carbon, DOC, Sleepers River Research Watershed, Vermont, VT, nitrogen load, streamflow, groundwater, nutrients, nutrient sources, water cycles, soil.

Relevant Websites:

2004 STAR Graduate Fellowship Conference Poster (PDF, 1p., 312KB, about PDF)

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.