Distribution of Acidophilic Microorganisms in Natural and Man-made Acidic Environments

Abstract

Acidophilic microorganisms can thrive in both natural and man-made environments. Natural acidic environments comprise hydrothermal sites on land or in the deep sea, cave systems, acid sulfate soils and acidic fens, as well as naturally exposed ore deposits (gossans). Man-made acidic environments are mostly mine sites including mine waste dumps and tailings, acid mine drainage and biomining operations. The biogeochemical cycles of sulfur and iron, rather than those of carbon and nitrogen, assume centre stage in these environments. Ferrous iron and reduced sulfur compounds originating from geothermal activity or mineral weathering provide energy sources for acidophilic, chemolithotrophic iron-and sulfur-oxidizing bacteria and archaea (including species that are autotrophic, heterotrophic or mixotrophic) and, in contrast to most other types of environments, these are often numerically dominant in acidic sites. Anaerobic growth of acidophiles can occur via the reduction of ferric iron, elemental sulfur or sulfate. While the activities of acidophiles can be harmful to the environment, as in the case of acid mine drainage, they can also be used for the extraction and recovery of metals, as in the case of biomining. Considering the important roles of acidophiles in biogeochemical cycles, pollution and biotechnology, there is a strong need to understanding of their physiology, biochemistry and ecology. Populations in natural acidic environmentsEnvironments where acid is formed naturally without the influence of mining include geothermal terrestrial sites (solfatara) that occur at active volcanoes, deep-sea hydrothermal systems, and naturally exposed sulfide ore deposits. These sites are of great interest when searching for organisms to be used, for example in biomining operations, as it is often the case that these environments have existed for many years and therefore indigenous microorganisms are potentially adapted to high metal and salt concentrations, extreme temperature and low pH (Table 10.1).

Enabling large-scale hydrogen storage in porous media – the scientific challenges

“…H2 loss by Fe(II) production, clogging laboratorial* 68,102,103,104,105,106 Please do not adjust margins Please do not adjust margins driven by the rate of stress change, but are often also timedependent, potentially giving rise to time-dependent (creep) deformation of the reservoir even during periods of no pore pressure change. When these processes occur within faults, it may affect their stability and frictional behaviour, thereby potentially affecting the economic and regulatory viability of the hydrogen storage complex.…”

Evolution of Predicted Acid Resistance Mechanisms in the Extremely Acidophilic Leptospirillum Genus

“…In contrast, extreme or "professional" acidophiles are organisms that thrive in extremely low pH environments (≤pH 3.5). They include Bacteria, Archaea, and Eukarya and are found widely distributed across the Tree of Life (reviewed in [1,[7][8][9][10]).…”

Extremophiles in Soil Communities of Former Copper Mining Sites of the East Harz Region (Germany) Reflected by Re-Analyzed 16S rRNA Data

“…The sample material (No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] is not any kind of typical natural soil, but surface material from the mine dumps, was brought from the ground to the surface during the site-related mining phases. The soil material was taken during dry weather periods.…”

“…19 has a special position between the soil samples of the ancient mining areas (No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] and the comparative samples (20)(21)(22)(23)(24)(25). In contrast to the ancient shaft hole places and small mine dumps, the base area of the industrial mine dump has no vegetation and nearly no humus formation.…”