title: Effects of environmental and biotic factors on carbon isotopic fractionation during decomposition of soil organic matter.
abstract: Decomposition of soil organic matter (SOM) plays an important role in the global carbon cycle because the CO2 emitted from soil respiration is an important source of atmospheric CO2. Carbon isotopic fractionation occurs during SOM decomposition, which leads to (12)C to enrich in the released CO2 while (13)C to enrich in the residual SOM. Understanding the isotope fractionation has been demonstrated to be helpful for studying the global carbon cycle. Soil and litter samples were collected from soil profiles at 27 different sites located along a vertical transect from 1200 to 4500 m above sea level (a.s.l.) in the south-eastern side of the Tibetan Plateau. Their carbon isotope ratios, C and N concentrations were measured. In addition, fiber and lignin in litter samples were also analyzed. Carbon isotope fractionation factor (α) during SOM decomposition was estimated indirectly as the slope of the relationship between carbon isotope ratios of SOM and soil C concentrations. This study shows that litter quality and soil water play a significant role in isotope fractionation during SOM decomposition, and the carbon isotope fractionation factor, α, increases with litter quality and soil water content. However, we found that temperature had no significant impact on the α variance.
authors.affiliation: Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Guoan
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yufu
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
mesh_terms: D002244:Carbon / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002247:Carbon Isotopes / Q000737:chemistry*; D005591:Chemical Fractionation / Q000379:methods; D004777:Environment; D008031:Lignin / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D013696:Temperature
chemical_list: D002247:Carbon Isotopes; D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon; D008031:Lignin