Acid mine drainage

Introduction

Acid mine drainage in a stream just outside of Pittsburgh, PA. [[1]]

Acid mine drainage (AMD) occurs when metal sulfides, most commonly pyrite, are exposed to and react with air and water. When water flows over or through sulfur-bearing mine tailings, a chemical reaction occurs between the water and rocks resulting in metal-rich water. AMD typically has a bright orange, yellow, or reddish color to it. The mine drainage is acidic, as its name states, and found around ore and coal mines. Abandoned and currently operating mining activities contribute to AMD. Metal rich drainage can also occur in areas that have not been mined. Areas like construction sites and other places that have been highly disturbed can exacerbate natural rock weathering processes leading to acidic drainage.

An area heavily mined for coal, therefore greatly impacted by AMD, is the mid-Atlantic region in the middle of the Appalachian Mountains. Here, and everywhere AMD occurs, has a highly altered ecosystem. The greatest consequence of AMD is water pollution. This in turn results in contaminated drinking water, damage to aquatic flora and fauna, and corrosion of man-made infrastructure.

Microorganisms like bacteria and archaea significantly affect AMD. When metal sulfides, usually pyrite, that are contained in rock are exposed to water and air, an oxidation reaction takes place. Microbes speed up the decomposition of these metal ions. Microorganisms also play a huge part in the bioremediation of AMD. Techniques that are being researched include using metal-immobilizing bacteria, biocontrol with bacteria and archaea, and bioleaching.

Physical environment

Describe the physical and chemical characteristics of the environment, using as many sections/subsections as you require. Look at other topics available in MicrobeWiki. Which involve processes similar to yours? Create links where relevant.

Biological interactions

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Microbial processes

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Key Microorganisms

What kind of microbes do we typically find in this environment? Or associated with important processes in this environment? Describe key groups of microbes that we find in this environment, and any special adaptations they may have evolved to survive in this environment. Add sections/subsections as needed. Look at other microbe listings in MicrobeWiki. Are some of the groups of microbes from your environment already described? Create links to those pages. Specific microbial populations will be included in the next section.

Examples of organisms within the group

Acicithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans and related species

Current Research

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References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Angela Kent at the University of Illinois at Urbana-Champaign.