Abstract
Soil microbes are major drivers of soil carbon cycling, yet we lack an understanding of how climate warming will affect microbial communities. Three ongoing field studies at the Harvard Forest Long-term Ecological Research (LTER) site (Petersham, MA) have warmed soils 5°C above ambient temperatures for 5, 8, and 20 years. We used this chronosequence to test the hypothesis that soil microbial communities have changed in response to chronic warming. Bacterial community composition was studied using Illumina sequencing of the 16S ribosomal RNA gene, and bacterial and fungal abundance were assessed using quantitative PCR. Only the 20-year warmed site exhibited significant change in bacterial community structure in the organic soil horizon, with no significant changes in the mineral soil. The dominant taxa, abundant at 0.1% or greater, represented 0.3% of the richness but nearly 50% of the observations (sequences). Individual members of the Actinobacteria, Alphaproteobacteria and Acidobacteria showed strong warming responses, with one Actinomycete decreasing from 4.5 to 1% relative abundance with warming. Ribosomal RNA copy number can obfuscate community profiles, but is also correlated with maximum growth rate or trophic strategy among bacteria. Ribosomal RNA copy number correction did not affect community profiles, but rRNA copy number was significantly decreased in warming plots compared to controls. Increased bacterial evenness, shifting beta diversity, decreased fungal abundance and increased abundance of bacteria with low rRNA operon copy number, including Alphaproteobacteria and Acidobacteria, together suggest that more or alternative niche space is being created over the course of long-term warming.
Department
Soil Biogeochemistry and Microbial Ecology
Publication Date
2-13-2015
Journal Title
Frontiers in Microbiology
Publisher
Frontiers
Digital Object Identifier (DOI)
Document Type
Article
Recommended Citation
DeAngelis KM, Pold G, Topçuoğlu BD, van Diepen LTA, Varney RM, Blanchard JL, Melillo J and Frey SD (2015) Long-term forest soil warming alters microbial communities in temperate forest soils. Front. Microbiol. 6:104. doi: 10.3389/fmicb.2015.00104
Rights
© 2015 DeAngelis, Pold, Topçuoğlu, van Diepen, Varney, Blanchard, Melillo and Frey.
Comments
This is an open access article published by Frontiers in Frontiers in Microbiology in 2015, available online: https://dx.doi.org/10.3389/fmicb.2015.00104