Microbial Iron Cycling in Acidic Geothermal Springs of Yellowstone National Park: Integrating Molecular Surveys, Geochemical Processes, and Isolation of Novel Fe-Active Microorganisms

A comprehensive study of acidic iron oxide mats in Yellowstone National Park's geothermal springs reveals that microbial community structure is intricately linked to iron cycling across a broad temperature range (53–88°C). The research integrates geochemical, molecular, and physiological analyses, identifying novel iron-oxidizing and iron-reducing microorganisms, including Sulfolobales str. MK5 and Acidicaldus str. MK6. These microbes exhibit distinct biomineralization patterns, producing ferric oxyhydroxides, K-jarosite, goethite, hematite, and scorodite under varying geochemical conditions. The study highlights the diverse metabolic strategies employed by these microorganisms, with some strains capable of autotrophic iron oxidation while others utilize mixotrophic pathways or anaerobic reduction of ferric iron.

Kozubal, M. A., Macur, R. E., Jay, Z. J., Beam, J. P., Malfatti, S. A., Tringe, S. G., Kocar, B. D., Borch, T., & Inskeep, W. P. (2012). Microbial Iron Cycling in Acidic Geothermal Springs of Yellowstone National Park: Integrating Molecular Surveys, Geochemical Processes, and Isolation of Novel Fe-Active Microorganisms. Frontiers in Microbiology, 3. https://doi.org/10.3389/fmicb.2012.00109