Grantee Research Project Results
Final Report: Microbial Community Diversity, Structural and Functional Responses to Multi-Component Metal Contamination of River Benthic Systems
EPA Grant Number: R829400E03Title: Microbial Community Diversity, Structural and Functional Responses to Multi-Component Metal Contamination of River Benthic Systems
Investigators: Holben, William E. , Gannon, James , Moore, Johnnie , Rillig, Matthias
Institution: University of Montana
EPA Project Officer: Chung, Serena
Project Period: September 24, 2001 through September 22, 2004
Project Amount: $375,000
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2000) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)
Objective:
The Montana U.S. Environmental Protection Agency (EPA)/Experimental Program to Stimulate Competitive Research (EPSCoR) program to Establish Research in the Biogeochemistry and Biological Effects of Toxic Metal from Historic Mining Activities consists of a Strategic Improvement Plan (SIP) and two Science and Engineering Environmental Research (SEER) projects. This report summarizes the activities of the SEER project carried out at the University of Montana, Missoula. The objective of this research project was to study the diversity, structure, and function of microbial communities in river sediments contaminated by multicomponent metals resulting from decades of mining activities. To understand the effect of metals on biological systems, experiments tested the effect of heavy metal exposure to microbial communities, which are considered primary actors in the watershed ecosystem, and analyzed their composition, physiological/metabolic activities, and chemical environment over time.
Summary/Accomplishments (Outputs/Outcomes):
Microbial communities inhabiting the hyporheic zone of six different river sites, encompassing a wide range of sediment metal loads resulting from large-scale base-metal mining activity in the region, were compared. No correlation was found between sediment metal content and the total hyporheic microbial biomass present within each site; however, the microbial community structure showed a significant linear relationship with the sediment metal loads. The abundance of four phylogenetic groups (Groups I, II, III, and IV) most closely related to a, b, and g-proteobacteria, and Cyanobacteria, respectively, were determined. Sediment metal content was correlated positively with Group II abundance and correlated negatively with Group III abundance. No correlation was apparent with regard to Group I or IV abundance. This is the first documentation of a relationship between fluvially deposited heavy metal contamination and hyporheic microbial community structure.
Further research showed no seasonal variation in the relationship between hyporheic microbial community structure and heavy metal contamination was determined; however, a strong and consistent linear relationship between the percent different in microbial community composition (populations present) and the difference in heavy metal content of hyporheic sediments throughout the year was demonstrated. Data on the abundance of the four specific phylogenetic groups suggested that the abundance of susceptible populations responded to heavy metals primarily during the seasons that hold the greatest potential for growth (i.e., the fall and early winter), when the most organic matter is deposited into regional streams.
Controlled laboratory experiments measured the rates of change in hyporheic microbial communities in response to heavy metal contamination at intervals during a 12-week period. There was a consistent, strong curvilinear relationship between community composition and heavy metal contamination, evident after only 7 days of metal exposure (i.e., short-term exposure). The abundance of each phylogenetic group was affected negatively by the heavy metal treatments; however, each group recovered from the metal treatments to a different extent and at unique rates. The structure of hyporheic microbial communities responded rapidly and at contamination levels an order of magnitude lower than those shown to elicit a response in aquatic macroinvertebrate assemblages. Collectively, these data indicate that hyporheic microbial communities are a sensitive and useful indicator of both long-term and short-term effects of heavy metal contamination in streams.
The final achievement of the grant was a comprehensive phylogenetic survey of the bacterial assemblage present in the hyporheic sediments of a noncontaminated freestone river in western Montana. A unique combined approach first fractionated the complex mixture of microbial community DNA based on percentage of G + C content, then exhaustively sampled each fraction through analysis of partial 16S rDNA sequences. The sequence information obtained provided the first major survey of freestone river bacterial communities and the sequence library obtained serve as a resource for future research efforts involving the development and application of quantitative PCR approaches for monitoring microbial community dynamics at various levels of resolution.
The expertise and approaches developed through the auspices of this EPA EPSCoR project were directly responsible for members of this group obtaining a 5-year National Science Foundation Microbial Observatory Program project to define more fully the interplay between microbes and the hyporheic environment in a western Montana river.
Journal Articles on this Report : 4 Displayed | Download in RIS Format
Other project views: | All 6 publications | 4 publications in selected types | All 4 journal articles |
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Feris KP, Ramsey PW, Frazar C, Rillig MC, Gannon JE, Holben WE. Structure and seasonal dynamics of hyporheic zone microbial communities in free-stone rivers of the western United States. Microbial Ecology 2003;46(2):200-215. |
R829400E02 (2003) R829400E03 (Final) |
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Feris KP, Ramsey PW, Frazar C, Rillig M, Moore JN, Gannon JE, Holben WE. Seasonal dynamics of shallow-hyporheic-zone microbial community structure along a heavy-metal contamination gradient. Applied and Environmental Microbiology 2004;70(4):2323-2331. |
R829400E02 (2003) R829400E03 (Final) |
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Feris KP, Ramsey PW, Rillig M, Moore JN, Gannon JE, Holben WE. Determining rates of change and evaluating group-level resiliency differences in hyporheic microbial communities in response to fluvial heavy-metal deposition. Applied and Environmental Microbiology 2004;70(8):4756-4765. |
R829400E02 (2003) R829400E03 (Final) |
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Feris K, Ramsey P, Frazar C, Moore JN, Gannon JE, Holben WE. Differences in hyporheic-zone microbial community structure along a heavy-metal contamination gradient. Applied and Environmental Microbiology 2003;69(9):5563-5573. |
R829400E02 (2003) R829400E03 (Final) |
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Supplemental Keywords:
microbial community, heavy metal, DNA, mining, restoration, indicators, Montana, pollutants/toxics, environmental monitoring, hazardous waste, mining wastes, environmental chemistry,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Water, Geographic Area, POLLUTANTS/TOXICS, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Arsenic, State, Chemicals, Monitoring/Modeling, Microbiology, Fate & Transport, Hazardous Waste, Environmental Monitoring, Water Pollutants, Ecology and Ecosystems, Hazardous, EPA Region, fate and transport, monitoring, aquatic ecosystem, contaminant dynamics, fate and transport , contaminant transport, mine tailings, Region 8, analytical chemistry, chemical kinetics, mining, chemical releases, groundwater contamination, Montana , chemical transport models, groundwater, heavy metals, mining wastes, mining impacted watershed, stream ecosystemProgress 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.