Grantee Research Project Results

Carbon Supply in a Subsurface Ecosystem: Sources, Patterns, and Response to Nitrogen Loading

EPA Grant Number: U915845
Title: Carbon Supply in a Subsurface Ecosystem: Sources, Patterns, and Response to Nitrogen Loading
Investigators: Gurwick, Noel P.
Institution: Cornell University
EPA Project Officer: Hahn, Intaek
Project Period: August 1, 2000 through August 1, 2003
Project Amount: $102,000
RFA: STAR Graduate Fellowships (2000) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology

Objective:

The goal of this research project is to compare carbon (C)-availability among morphologically distinct organic matter patches in C-poor subsurface soils below the water table and to use paired site comparisons to assess feedback between groundwater nitrogen (N) loading and root-derived (C)-supply in subsurface ecosystems.

Approach:

To understand sources of microbially available C in subsurface riparian ecosystems, the investigator is conducting laboratory studies using aerobic incubations. Within-site spatial variation in C-availability is being assessed using 1-meter long soil cores taken from: (1) a transect through poorly-drained glacial outwash; and (2) a transect along a steep hydrology-vegetation gradient. These cores are also being used in combination with soil pits to characterize soil profiles, and to measure root biomass, total C, and soil particle size distribution. To assess variation in C-avalability among subsurface patches, characteristic patch material (e.g., lenses, buried horizons, root channels) is being incubated.

To assess feedback between N-loading and C-supply, root production, C-availability in soil, C:N ratios in belowground biomass, and in-situ decomposition rates will be compared between paired sites differing primarily in the magnitude of subsurface N-loads. This comparison will be interpreted as a long-term fertilization experiment. Root production will be measured using ingrowth cores, and root biomass will be measured using static cores to 1 meter.

Expected Results:

This study is expected to result in a better understanding of microbially availalble C in subsurface riparian ecosystems.

Supplemental Keywords:

spatial heterogeneity, carbon cycle, coastal eutrophication, root production, riparian zone, hydrology, watershed, biogeochemistry., RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Water & Watershed, Ecosystem/Assessment/Indicators, Environmental Chemistry, Geochemistry, Aquatic Ecosystem, Ecological Effects - Environmental Exposure & Risk, Ecology and Ecosystems, Watersheds, Ecological Indicators, nutrient dynamics, bioassessment, soil water chemistry, nitrogen loading, ecosystem processes, sediment core, nitrogen cycling, Riparian ecosystem, biogeochemcial cycling, sediment metabolism, biomass, nitrogen inputs, aquatic ecosystems, carbon exchange, carbon flux, carbon availability, carbon storage, nitrogen uptake, carbon supply, aquatic ecology, riparian habitat, watershed assessment, nitrogen, ecological research, groundwater, riparian ecosytem integrity

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.