title: Response of stable carbon isotope in epilithic mosses to atmospheric nitrogen deposition.
abstract: Epilithic mosses are characterized by insulation from substratum N and hence meet their N demand only by deposited N. This study investigated tissue C, total Chl and delta13C of epilithic mosses along 2 transects across Guiyang urban (SW China), aiming at testing their responses to N deposition. Tissue C and total Chl decreased from the urban to rural, but delta13C(moss) became less negative. With measurements of atmospheric CO2 and delta13CO2, elevated N deposition was inferred as a primary factor for changes in moss C and isotopic signatures. Correlations between total Chl, tissue C and N signals indicated a nutritional effect on C fixation of epilithic mosses, but the response of delta13C(moss) to N deposition could not be clearly differentiated from effects of other factors. Collective evidences suggest that C signals of epilithic mosses are useful proxies for N deposition but further works on physiological mechanisms are still needed.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China. liuxueyan@vip.skleg.cn
authors.forename: Xue-Yan
authors.initials: XY
authors.lastname: Liu
authors.forename: Hua-Yun
authors.initials: HY
authors.lastname: Xiao
authors.forename: Cong-Qiang
authors.initials: CQ
authors.lastname: Liu
authors.forename: You-Yi
authors.initials: YY
authors.lastname: Li
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Xiao
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000032:analysis; D044002:Bryophyta / Q000737:chemistry / Q000254:growth & development*; D002245:Carbon Dioxide / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis; D002681:China; D004784:Environmental Monitoring / Q000379:methods; D009584:Nitrogen / Q000032:analysis*; D014507:Urbanization
chemical_list: D000393:Air Pollutants; D002247:Carbon Isotopes; D002245:Carbon Dioxide; D009584:Nitrogen