title: Temperature sensitivity of soil respiration rates enhanced by microbial community response.
abstract: Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.
authors.affiliation: 1] Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK [2] Department of Forest Sciences, University of Helsinki, 00014 Helsinki, Finland.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Karhu
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Auffret
authors.affiliation: Rothamsted Research-North Wyke, Okehampton, Devon EX20 2SB, UK.
authors.forename: Jennifer A J
authors.initials: JA
authors.lastname: Dungait
authors.affiliation: School of Agriculture, Food &Environment, The Royal Agricultural University, Cirencester, Gloucestershire GL7 6JS, UK.
authors.forename: David W
authors.initials: DW
authors.lastname: Hopkins
authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3UU, UK.
authors.forename: James I
authors.initials: JI
authors.lastname: Prosser
authors.affiliation: Hawkesbury Institute for the Environment, University of Western Sydney, Penrith 2751, New South Wales, Australia.
authors.forename: Brajesh K
authors.initials: BK
authors.lastname: Singh
authors.affiliation: School of Natural Sciences, Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK.
authors.forename: Jens-Arne
authors.initials: JA
authors.lastname: Subke
authors.affiliation: School of Life Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Wookey
authors.affiliation: Department of Ecology, Swedish University of Agricultural Sciences (SLU), 750 07 Uppsala, Sweden.
authors.forename: Göran I
authors.initials: GI
authors.lastname: Agren
authors.affiliation: 1] Laboratory of Functional Ecology and Global Change, Forest Sciences Centre of Catalonia (CTFC), 25280 Solsona, Spain [2] Department of Horticulture, Botany and Landscaping, School of Agrifood and Forestry Science and Engineering, University of Lleida, 25198 Lleida, Spain.
authors.forename: Maria-Teresa
authors.initials: MT
authors.lastname: Sebastià
authors.affiliation: Laboratory of Functional Ecology and Global Change, Forest Sciences Centre of Catalonia (CTFC), 25280 Solsona, Spain.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Gouriveau
authors.affiliation: Department of Crop Production Ecology, Swedish University of Agricultural Sciences (SLU), 750 07 Uppsala, Sweden.
authors.forename: Göran
authors.initials: G
authors.lastname: Bergkvist
authors.affiliation: 1] School of Geosciences, University of Edinburgh, Edinburgh EH8 9XP, UK [2] Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Patrick
authors.initials: P
authors.lastname: Meir
authors.affiliation: School of Geosciences, University of Edinburgh, Edinburgh EH8 9XP, UK.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Nottingham
authors.affiliation: Seccion Quimica, Pontificia Universidad Catolica del Peru, Lima 32, Peru.
authors.forename: Norma
authors.initials: N
authors.lastname: Salinas
authors.affiliation: Geography, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4RJ, UK.
authors.forename: Iain P
authors.initials: IP
authors.lastname: Hartley
mesh_terms: D001110:Arctic Regions; D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D003081:Cold Climate; D005246:Feedback; D057232:Global Warming; D009584:Nitrogen / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013696:Temperature; D014329:Tropical Climate
chemical_list: D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen