Grantee Research Project Results
Final Report: UM SEER: Determining the Role of Microbial Community Structure and Function in Establishing the Health of Multicomponent-Metal Contaminated River Benthic Systems
EPA Grant Number: R827457E02Title: UM SEER: Determining the Role of Microbial Community Structure and Function in Establishing the Health of Multicomponent-Metal Contaminated River Benthic Systems
Investigators: Holben, William E. , Gannon, James , Moore, Johnnie
Institution: University of Montana
EPA Project Officer: Chung, Serena
Project Period: July 1, 1999 through June 30, 2002
Project Amount: $140,000
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (1998) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)
Objective:
The objective of this research project was to determine the impact of fluvially deposited metal contamination on the structure and function of microbial communities in riverine systems. Four hypotheses regarding the effects of heavy metals on water and watersheds contaminated with metals from past mining operations were addressed: (1) initial exposure to metals inhibits or kills sensitive organisms leaving tolerant populations as dominant, resulting in an initial net decrease in diversity; (2) gradual changes occur in the microbial community over time as the resident community becomes more tolerant of metal contamination; (3) decreased apparent toxicity from metal contamination occurs with prolonged exposure; and (4) these bacterial community changes have fundamental implications for determining the ecological health of watersheds because of the primary role bacteria play in a host of biogeochemical processes and their position at the base of the ecosystem trophic structure.
Using a suite of molecular and activity-based techniques, we demonstrated that fluvially deposited metals have a measurable effect on microbial communities. Research performed under this U.S. Environmental Protection Agency-Experimental Program to Stimulate Competitive Research (EPSCoR) project has formed the basis for several theses to fulfill the degree requirements of two Ph.D. students (Kevin Feris, Ph.D. expected 4/03; Philip Ramsey, Ph.D. expected 8/04), and one M.S. student (Chris Frazar, M.S. granted 5/02). In addition, six undergraduate students gained valuable laboratory and research experience serving as laboratory aides or conducting independent research projects supported by, or related to, the funded research.
Summary/Accomplishments (Outputs/Outcomes):
Microbial communities are exquisitely sensitive bioindicators of natural resource damage. The techniques employed here reveal significant metal effects on microbial community structure at metal levels at least an order of magnitude lower than minimal levels required to see detectable effects in macroinvertebrates. The findings of this research project are as follows:
· Short-term effects of metal contamination include impacts on microbial community structure and function (measured as total community activity).
· Long-term effects of metals on microbial communities are primarily exhibited at the level of community composition, but not altered activity or total biomass. This indicates that, with prolonged exposure, metal tolerant microbial populations allow the system to achieve its carrying capacity with regard to the microbial community.
· Higher metal concentrations at constant pH and lower pH at constant metal concentrations both affect community productivity. Thus, there may be synergistically enhanced impacts in environments where pH is lower as a result of metal contamination.
Supplemental Keywords:
ecological health, watersheds, arsenic, microbial community and structure, ecological effects, bacteria, heavy metal, DNA, restoration, indicators, Northwest United States, Montana, MT, aquatic biota, aquatic ecology, biochemical indicators, biodegradation, biodiversity, bioremediation, bioremediation of soils, contaminated groundwater, contaminated sediment, ecological assessment, ecosystem assessment, ecosystem indicators, environmental stress indicators, groundwater, hazardous waste treatment, heavy metal contamination, heavy metals, microbial communities, microbial degradation., RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Waste, Water, ECOSYSTEMS, Hazardous, Ecological Indicators, Chemical Engineering, Ecosystem Protection, Environmental Chemistry, Ecosystem/Assessment/Indicators, Contaminated Sediments, exploratory research environmental biology, Monitoring/Modeling, Hazardous Waste, Ecological Monitoring, Ecological Effects - Environmental Exposure & Risk, Biochemistry, heavy metals, aquatic biota , bioremediation of soils, contaminated sediment, microbial degradation, biodiversity, ecosystem assessment, aquatic ecology, hazardous waste treatment, redox, ecological assessment, contaminated groundwater, ecosystem indicators, biodegradation, bioremediation, groundwater, biochemical indicators, environmental stress indicators, heavy metal contaminationProgress and Final Reports:
Original AbstractThe 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.