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Mesophilic Mineral-Weathering Bacteria Inhabit the Critical-Zone of a Perennially Cold Basaltic Environment

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Original languageEnglish
Pages (from-to)52-62
Number of pages11
JournalGeomicrobiology journal
Volume33
Issue number1
DOIs
Publication statusPublished - 2 Jan 2016

Abstract

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 and their ability to solubilize 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 degrees C), despite critical-zone temperatures that were continuously below 15 degrees C, although all isolates could grow at temperatures associated with the critical-zone (-2.8-13.1 degrees 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 persistance in this environment. Moreover, our study showed that the cold basaltic critical-zone is a region of active phosphate mineral-weathering.

    Research areas

  • bacteria, critical-zone, MPS, soil microbiology, weathering, PHOSPHATE-SOLUBILIZING BACTERIA, 16S RIBOSOMAL-RNA, SILICATE ROCKS, TEMPERATURE, SOIL, PLANTS, GENES, RATES, ICELAND, GROWTH

ID: 25221552