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Visualization of In-Situ Douglas Fir Roots and Ectomycorrhizae in the Context of Phyto Remediation of Acid Mine Wastes
Primary Issue Addressed: Sustainability
Secondary Issue Addressed: Characterization
Project Site: Badger Mine site, Butte, Montana, and Montana Tech Greenhouse
Collaborating Entities: Montana Tech
Cost Share: None
Project Description
Douglas fir (Pseudotsuga menziesii) is a coniferous evergreen tree with the capacity to colonize harsh and severe environments. Douglas fir may have physiological attributes allowing it to survive while being exposed to the potentially toxic levels of metals and low soil pH of acid mine wastes. These attributes may include fine root respiration rates indicative of an active metabolism, root turnover rates, resistance to metal toxicity, and/or ectomycorrhizal fungi associated with Douglas fir roots. For this project, the physiology of ectomycorrhizal Douglas fir will be investigated in the context of contaminated mine wastes and low soil pH. Ultimately, ectomycorrhizal fungi from the Douglas fir tree may be used in biological remediation processes and as a stabilizing agent for mine wastes. The objectives of this research are to: 1) define physiological attributes of Douglas fir trees that allow it to tolerate toxic soils; 2) determine whether the addition of ectomycorrhizal fungi provides a growth advantage for trees in these types of soils; and 3) install a minirhizotron to assess the development of Douglas fir root systems.
Status
Seedlings were planted at both the Badger Mine site and in the Montana Tech greenhouse in the autumn of 2004. In August 2005, survival rates were quantified as follows: Badger Mine site, mycorrhizal 20%, Badger Mine site nonmycorrhizal 7.5%, greenhouse mycorrhizal 90%, greenhouse nonmycorrhizal 70%. The autumn and winter of 2004 were unusually dry, which may have played a role in the poor survival rate of the Badger Mine site seedlings.
Ecophysiolgical measurements of both Badger Mine site seedlings and greenhouse seedlings began in November 2005. Flourescence and chlorophyll content measurements were completed within the month, while respiration measurements took longer due to calibration and warm-up requirements for the equipment. This extended measurement time was facilitated by harvesting entire seedlings and associated soil and keeping them alive in the laboratory.
Vegetative samples of both living and dead seedlings, along with soil samples, were submitted for metals analysis. Interpretation of analytical results is pending. An in-depth evaluation and analysis of the data will be provided in the final report that is expected to be completed in fiscal 2006.