title: The Role of Microbial Community Composition in Controlling Soil Respiration Responses to Temperature.
abstract: Rising global temperatures may increase the rates of soil organic matter decomposition by heterotrophic microorganisms, potentially accelerating climate change further by releasing additional carbon dioxide (CO2) to the atmosphere. However, the possibility that microbial community responses to prolonged warming may modify the temperature sensitivity of soil respiration creates large uncertainty in the strength of this positive feedback. Both compensatory responses (decreasing temperature sensitivity of soil respiration in the long-term) and enhancing responses (increasing temperature sensitivity) have been reported, but the mechanisms underlying these responses are poorly understood. In this study, microbial biomass, community structure and the activities of dehydrogenase and β-glucosidase enzymes were determined for 18 soils that had previously demonstrated either no response or varying magnitude of enhancing or compensatory responses of temperature sensitivity of heterotrophic microbial respiration to prolonged cooling. The soil cooling approach, in contrast to warming experiments, discriminates between microbial community responses and the consequences of substrate depletion, by minimising changes in substrate availability. The initial microbial community composition, determined by molecular analysis of soils showing contrasting respiration responses to cooling, provided evidence that the magnitude of enhancing responses was partly related to microbial community composition. There was also evidence that higher relative abundance of saprophytic Basidiomycota may explain the compensatory response observed in one soil, but neither microbial biomass nor enzymatic capacity were significantly affected by cooling. Our findings emphasise the key importance of soil microbial community responses for feedbacks to global change, but also highlight important areas where our understanding remains limited.
authors: University of Aberdeen, Cruickshank Building St Machar Drive, Aberdeen AB24 3UU, United Kingdom.
authors: Marc D
authors: http://orcid.org/0000-0002-2321-8219
authors: MD
authors: Auffret
authors: University of Exeter Amory Building, Rennes Drive, Exeter EX4 4RJ, United Kingdom.
authors: Kristiina
authors: K
authors: Karhu
authors: Hawkesbury Institute for the Environment, University of Western Sydney, Penrith 2751 NSW, Australia.
authors: Amit
authors: A
authors: Khachane
authors: Sustainable Soils and Grassland Systems Department, Rothamsted Research North Wyke, Okehampton, EX20 2SB, United Kingdom.
authors: Jennifer A J
authors: JA
authors: Dungait
authors: School of Energy, Environment and Agrifood, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, United Kingdom.
authors: Fiona
authors: F
authors: Fraser
authors: The Royal Agricultural University, Cirencester, Gloucestershire, GL7 6JS, United Kingdom.
authors: David W
authors: DW
authors: Hopkins
authors: Institute of Life & Earth Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom.
authors: Philip A
authors: PA
authors: Wookey
authors: Hawkesbury Institute for the Environment, University of Western Sydney, Penrith 2751 NSW, Australia.
authors: Brajesh K
authors: BK
authors: Singh
authors: The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, United Kingdom.
authors: Thomas E
authors: TE
authors: Freitag
authors: University of Exeter Amory Building, Rennes Drive, Exeter EX4 4RJ, United Kingdom.
authors: Iain P
authors: IP
authors: Hartley
authors: University of Aberdeen, Cruickshank Building St Machar Drive, Aberdeen AB24 3UU, United Kingdom.
authors: James I
authors: JI
authors: Prosser
mesh_terms: D018533:Biomass; D019069:Cell Respiration; D005651:Fumigation; D016014:Linear Models; D064307:Microbiota; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors
chemical_list: D012987:Soil