title: Convergence of microbial assimilations of soil carbon, nitrogen, phosphorus, and sulfur in terrestrial ecosystems.
abstract: How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P, and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P and S, implying a unifying mechanism of microbial assimilating soil elements. This correlation explains the well-constrained C:N:P:S stoichiometry with a slightly larger variation in soils than in microbial biomass. Meanwhile, it is estimated that the minimum requirements of soil elements for soil microbes are 0.8 mmol C Kg(-1) dry soil, 0.1 mmol N Kg(-1) dry soil, 0.1 mmol P Kg(-1) dry soil, and 0.1 mmol S Kg(-1) dry soil, respectively. These findings provide a mathematical explanation of element imbalance in soils and soil microbial biomass, and offer insights for incorporating microbial contribution to nutrient cycling into Earth system models.
authors.affiliation: Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79902, USA.|Climate Change Science Institute and Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.|Biology Department, San Diego State University, San Diego, CA 92182, USA.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Biological Sciences, Tennessee State University, Nashville, TN 37209, USA.
authors.forename: Dafeng
authors.initials: D
authors.lastname: Hui
authors.affiliation: Climate Change Science Institute and Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Anthony W
authors.initials: AW
authors.lastname: King
authors.affiliation: Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, 79902, USA.|Climate Change Science Institute and Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Xia
authors.initials: X
authors.lastname: Song
authors.affiliation: Climate Change Science Institute and Environmental Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Thornton
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lihua
authors.initials: L
authors.lastname: Zhang
mesh_terms: D018533:Biomass; D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D017753:Ecosystem; D008827:Microbiological Phenomena; D015233:Models, Statistical; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D010758:Phosphorus / Q000737:chemistry / Q000378:metabolism*; D012044:Regression Analysis; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism*
chemical_list: D012987:Soil; D010758:Phosphorus; D013455:Sulfur; D002244:Carbon; D009584:Nitrogen