Microbial communities in terrestrial surface soils are not widely limited by carbon |
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| Authors: | Yongxing Cui Shushi Peng Manuel Delgado-Baquerizo Matthias C. Rillig César Terrer Biao Zhu Xin Jing Ji Chen Jinquan Li Jiao Feng Yue He Linchuan Fang Daryl L. Moorhead Robert L. Sinsabaugh Josep Peñuelas |
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| Affiliation: | 1. Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China;2. Laboratorio de Biodiversidad y Funcionamiento Ecosistémico, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Sevilla, Spain;3. Institute of Biology, Freie Universität Berlin, Berlin, Germany;4. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Boston, Massachusetts, USA;5. Institute of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, China;6. State Key Laboratory of Grassland Agro-Ecosystems, and College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, Gansu, China;7. Department of Agroecology, Aarhus University, Tjele, Denmark;8. Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Institute of Biodiversity Science and Institute of Eco-Chongming, School of Life Sciences, Fudan University, Shanghai, China;9. College of Resources and Environment, Huazhong Agricultural University, Wuhan, China;10. School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan, China;11. Department of Environmental Sciences, University of Toledo, Toledo, Ohio, USA;12. Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA;13. CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain |
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| Abstract: | Microbial communities in soils are generally considered to be limited by carbon (C), which could be a crucial control for basic soil functions and responses of microbial heterotrophic metabolism to climate change. However, global soil microbial C limitation (MCL) has rarely been estimated and is poorly understood. Here, we predicted MCL, defined as limited availability of substrate C relative to nitrogen and/or phosphorus to meet microbial metabolic requirements, based on the thresholds of extracellular enzyme activity across 847 sites (2476 observations) representing global natural ecosystems. Results showed that only about 22% of global sites in terrestrial surface soils show relative C limitation in microbial community. This finding challenges the conventional hypothesis of ubiquitous C limitation for soil microbial metabolism. The limited geographic extent of C limitation in our study was mainly attributed to plant litter, rather than soil organic matter that has been processed by microbes, serving as the dominant C source for microbial acquisition. We also identified a significant latitudinal pattern of predicted MCL with larger C limitation at mid- to high latitudes, whereas this limitation was generally absent in the tropics. Moreover, MCL significantly constrained the rates of soil heterotrophic respiration, suggesting a potentially larger relative increase in respiration at mid- to high latitudes than low latitudes, if climate change increases primary productivity that alleviates MCL at higher latitudes. Our study provides the first global estimates of MCL, advancing our understanding of terrestrial C cycling and microbial metabolic feedback under global climate change. |
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| Keywords: | decomposer community ecological stoichiometry global climate change heterotrophic respiration resource limitations soil carbon cycling soil-climate feedback |
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