Assessment of soil microbial communities involved in cellulose utilization at two contrasting Alpine forest sites
Abstract
Soil microbial communities involved in C-13-labeled cellulose utilization from two contrasting (in terms of vegetation and climatic conditions) forest sites at different elevations were studied by using a laboratory microcosm experiment and a PLFA (phospholipid fatty acid)-SIP (stable isotope probing) approach considering the effects of incubation temperature (0, 10 and 20 degrees C) and time (1-4 weeks). The amounts of cellulose-C-13 assimilated by soil microorganisms and the composition of microbial communities utilizing cellulose were site dependent.
Total, bacterial and actinobacterial biomass incorporated higher amounts of C-13 in soil from the deciduous forest site (at the lower elevation), while fungal biomass contained increased amounts of C-13 in soil from the coniferous forest site (at the higher elevation). Increasing temperatures resulted in increased amounts of C-13 assimilated by the different PLFA-based microbial groups, except fungi, and in significant changes in the community structure of cellulose utilizers.
Fungi were better adapted to cold conditions than bacteria. Longer incubation times determined an increase in the amount of C-13 incorporated into total and bacterial PLFAs but had no effect on the composition of labeled microbial communities.