Grantee Research Project Results
Sediment Entrainment and Stream Benthic Communities: Implications for Freshwater BioassessmentEPA Grant Number: U915239
Title: Sediment Entrainment and Stream Benthic Communities: Implications for Freshwater Bioassessment
Investigators: Kenworthy, Stephen T.
Institution: Johns Hopkins University
EPA Project Officer: Edwards, Jason
Project Period: December 1, 1997 through December 1, 2000
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1997)
Research Category: Fellowship - Geography , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The goal of this research project is to document how the spatial and temporal characteristics of sediment disturbance influence the composition of benthic invertebrate communities in streams. The intensity of sediment entrainment and transport will be related to changes in the relative abundance of benthic macroinvertebrate taxa. This information will be used to evaluate the influence of sediment dynamics on stream benthos in different fluvial settings, and to infer likely biological responses to changes in watershed hydrology and sediment loading.Approach:
The research includes experimental investigation of the effects of sediment entrainment and transport on benthic organisms and simulation of sediment disturbance and benthic community dynamics in settings that differ in hydrologic and bed material characteristics. The experimental work involves treatment of aquatic insect populations with flow and substrate disturbances of varying intensity in an artificial stream. The composition of experimental sediment beds is designed to replicate gravel-bed river surface structure. The selection of organisms is based on behavioral and physical characteristics expected to produce differential responses to substrate disturbance. The degree of sediment entrainment and transport is carefully controlled, and the resulting washout and mortality of benthic organisms is measured. Simulation of disturbance-response dynamics will utilize the results of the laboratory work to explore the influence of hydrologic regime, river bed topography, and substrate composition on the spatial pattern and taxonomic structure of benthic communities in gravel-bed channels.Expected Results:
The experiments will provide data on the mortality and displacement of benthic invertebrates as a function of flow strength, sediment characteristics, and organism traits.Supplemental Keywords:
fellowship, benthos, disturbance, biomonitoring.