Long-term warming in a Mediterranean-type grassland affects soil bacterial functional potential but not bacterial taxonomic composition.


Gao Y(1)(2), Ding J(2)(3), Yuan M(4), Chiariello N(5), Docherty K(6), Field C(5), Gao Q(2), Gu B(7), Gutknecht J(8)(9), Hungate BA(10)(11), Le Roux X(12), Niboyet A(13)(14), Qi Q(2), Shi Z(4), Zhou J(2)(4)(15), Yang Y(16).
Author information:
(1)Institute of Desertification Studies, Chinese Academy of Forestry, Beijing, China.
(2)State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
(3)Key Laboratory of Dryland Agriculture, Ministry of Agriculture of the People's Republic of China, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China.
(4)Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA.
(5)Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA.
(6)Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA.
(7)Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
(8)Department of Soil Ecology, Helmholtz Centre for Environmental Research - UFZ, Halle, Germany.
(9)Department of Soil, Water, and Climate, University of Minnesota, Twin Cities, Saint Paul, MN, USA.
(10)Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
(11)Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
(12)Mirobial Ecology Centre LEM, INRA, CNRS, University of Lyon, University Lyon 1, UMR INRA 1418, Villeurbanne, France.
(13)Institut d'Ecologie et des Sciences de l'Environnement de Paris
(Sorbonne Université, CNRS, INRA, IRD, Université Paris Diderot, UPEC), Paris, France.
(14)AgroParisTech, Paris, France.
(15)Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
(16)State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China. [Email]


Climate warming is known to impact ecosystem composition and functioning. However, it remains largely unclear how soil microbial communities respond to long-term, moderate warming. In this study, we used Illumina sequencing and microarrays (GeoChip 5.0) to analyze taxonomic and functional gene compositions of the soil microbial community after 14 years of warming (at 0.8-1.0 °C for 10 years and then 1.5-2.0 °C for 4 years) in a Californian grassland. Long-term warming had no detectable effect on the taxonomic composition of soil bacterial community, nor on any plant or abiotic soil variables. In contrast, functional gene compositions differed between warming and control for bacterial, archaeal, and fungal communities. Functional genes associated with labile carbon (C) degradation increased in relative abundance in the warming treatment, whereas those associated with recalcitrant C degradation decreased. A number of functional genes associated with nitrogen (N) cycling (e.g., denitrifying genes encoding nitrate-, nitrite-, and nitrous oxidereductases) decreased, whereas nifH gene encoding nitrogenase increased in the warming treatment. These results suggest that microbial functional potentials are more sensitive to long-term moderate warming than the taxonomic composition of microbial community.