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Metal Biogeochemistry
        in Mineralized Areas: Impacts on Ecosystem Healths: Steve W. Blecker

Project Title: Metal Biogeochemistry in Mineralized Areas: Impacts on Ecosystem Healths
Mendenhall Fellow: Steve W. Blecker, (775)784-5036,
Duty Station: Reno, NV
Start Date: December 10, 2007
Education: Ph.D., Soil Science, Colorado State University, 2005
Research Advisors: Lisa Stillings,; Larry Gough,; Paul Lamothe,; Milan Pavich,; Bronwen Wang,; Michael Amacher (USDA-Forest Service),; Cheryl Mackowiak (University of Florida),
  Steve Blecker

Project Description:

Studies of soil quality and ecosystem health employ a wide variety of approaches designed to monitor ecosystem functioning impacted from an array of natural and anthropogenic disturbances. Definitions of soil health, though varied, typically involve the soil's role in mediating nutrient, water and energy cycles in support of associated flora and fauna. The limited mobility and inherent sensitivity of soil microbial communities to external stressors makes them well suited to study ecosystem health, though this sensitivity and variability can complicate interpretation. Measures of plant community characteristics can provide a more complete picture of the impact that a particular disturbance or condition may have on an ecosystem; especially considering the importance of vegetation in phytoremediation, impact on the hydrologic cycle, and nutritional value to fauna.

The focus of this study is on metal-microbe-vegetation interactions in mineralized terrestrial ecosystems, and the potential impact on ecosystem functioning (for example, microbial activity), and plant community biomass and composition. This study is designed to provide a toolbox of procedures from which the appropriate ecosystem measures can be applied, based on site and disturbance characteristics, in support of geoenvironmental assessments, reclamation monitoring and other studies of ecosystem health. In addition, a hierarchy of sampling intensity and analyses could be established based on budget and personnel constraints.

An extensive reconnaissance study (Phase 1) within several Western U.S. mining districts of contrasting mineralogy and/or climate will be carried out in order to examine metal biogeochemical interaction between mineralized and adjoining non-mineralized areas and test the utility of these measures in different systems. Phase 2 will involve a more intensive examination at one or two of these sites, incorporating spatial and/or temporal (for example, seasonal) variability. Biotic response measures will include soil microbial biomass, enzyme activity and functional diversity, along with vegetation productivity, composition and metal content. Abiotic parameters will include sequential metal extraction (to identify more labile or bioavailable phases) and associated parameters.

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