Frequent freeze-thaw cycles yield diminished yet resistant and responsive microbial communities in two temperate soils

• Published in: FEMS Microbiology Ecology
• Main Authors: Stres, Blaž, Faganeli, Jadran, Tiedje, James M., Philippot, Laurent
• Format: Other/Unknown Material
• Language: English
• Published: Elsevier 2016
• Subjects: mikrobiologija; mikrobi; nizke temperature; adaptacija; info:eu-repo/classification/udc/579; permafrost
• Online Access: https://repozitorij.uni-lj.si/IzpisGradiva.php?id=83238; https://repozitorij.uni-lj.si/Dokument.php?id=85367&dn=; http://www.cobiss.si/scripts/cobiss?command=DISPLAY&base=cobib&rid=2671752&fmt=11

Few studies have been conducted on adaptations of microbial communities to low and fluctuating temperatures using environmentally relevant conditions. In this study, six Himalayan and two temperate soils were selected as candidates for low temperature/freeze-thaw (FT) adapted and susceptible soils, respectively. Redundancy analysis with foward selection was used to create a model of environmental parameters explaining variability in initial microbial abundance and 4oC activities. The best predictor was soil carbon, explaining more than 74% of data variability (P=0.002), despite significant differences in soil characteristics and environmental history. We tested the hypothesis that the reproduced Hymalayan FT fluctuations selected physiologically similar communities in distinct soils. Microcosmos were experimentally subjected to two separate 50 and 60 FT-cycle experiments. Significant decrease in abundance, 4oC basal respiration and drastic rearrangements in community-level physiological profiles (CLPP) were observed in microcosmos with temperate soils until 40 FT cycles. CLPP remained distinct from those of the Himalayan soils. Minor changes were observed in the Hymalayan soils confirming that microbial populations with physiological traits consistent with the non-continous permafrost conditions reside in the Himalayan soils whereas the surviving temperature soil microbes actively adjusted to novel environmental conditions.