Mesophilic mineral-weathering bacteria inhabit the critical-zone of a perennially cold basaltic environment

Summers, Stephen; Thomson, Bruce C.; Whiteley, Andrew and Cockell, Charles S. (2016). Mesophilic mineral-weathering bacteria inhabit the critical-zone of a perennially cold basaltic environment. Geomicrobiology Journal, 33(1) pp. 52–62.



The weathering of silicate in the world’s critical-zone (rock-soil interface) is a natural mechanism providing a feedback on atmospheric CO2 concentrations through the carbonate-silicate cycle. We examined culturable bacterial communities from a critical-zone in western Iceland to determine the optimum growth temperature, ability to solubilise phosphate-containing minerals, which are abundant within the critical-zone area examined here. The majority of isolated bacteria were able to solubilize mineral-state phosphate. Almost all bacterial isolates were mesophilic (growth optima of 20-45°C), despite critical-zone temperatures that were continuously below 15°C, although all isolates could grow at temperatures associated with the critical-zone (-2.8 – 13.1°C). Only three isolates were shown to have thermal optima for growth that were within temperatures experienced at the critical-zone. These findings show that the bacteria that inhabit the western Icelandic critical-zone have temperature growth optima suboptimally adapted to their environment, implying that other adaptations may be more important for their long-term persistence in this environment. Moreover, our study showed that the cold basaltic critical-zone is a region of active phosphate mineral-weathering.

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  • Item ORO ID
  • 43257
  • Item Type
  • Journal Item
  • ISSN
  • 1521-0529
  • Project Funding Details
  • Funded Project NameProject IDFunding Body
    Not SetNot SetThe Centre for Ecology and Hydrology, UK
    Not SetNot SetThe Open University, UK
  • Keywords
  • critical-zone; weathering; bacteria; MPS; soil microbiology
  • Academic Unit or School
  • Faculty of Science, Technology, Engineering and Mathematics (STEM)
  • Copyright Holders
  • © 2016 Taylor and Francis
  • Depositing User
  • Stephen Summers