title: Ammonium first: natural mosses prefer atmospheric ammonium but vary utilization of dissolved organic nitrogen depending on habitat and nitrogen deposition.
abstract: Mosses, among all types of terrestrial vegetation, are excellent scavengers of anthropogenic nitrogen (N), but their utilization of dissolved organic N (DON) and their reliance on atmospheric N remain uncharacterized in natural environments, which obscures their roles in N cycles. Natural (15) N abundance of N sources (nitrate (NO(3)(-)), ammonium (NH(4)(+)) and DON in deposition and soil) for epilithic and terricolous mosses was analyzed at sites with different N depositions at Guiyang, China. Moss NO(3)(-) assimilation was inhibited substantially by the high supply of NH(4)(+) and DON. Therefore, contributions of NH(4)(+) and DON to moss N were partitioned using isotopic mass-balance methods. The N contributions averaged 56% and 46% from atmospheric NH(4)(+), and 44% and 17% from atmospheric DON in epilithic and terricolous mosses, respectively. In terricolous mosses, soil NH(4)(+) and soil DON accounted for 16% and 21% of bulk N, which are higher than current estimations obtained using (15) N-labeling methods. Moreover, anthropogenic NH(4)(+) deposition suppressed utilization of DON and soil N because of the preference of moss for NH(4)(+) under elevated NH(4)(+) deposition. These results underscore the dominance of, and preference for, atmospheric NH(4)(+) in moss N utilization, and highlight the importance of considering DON and soil N sources when estimating moss N sequestration and the impacts of N deposition on mosses.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.|Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 1838509, Japan.
authors.forename: Xue-Yan
authors.initials: XY
authors.lastname: Liu
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 1838509, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Koba
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 1838509, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Makabe
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Li
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, 1838509, Japan.
authors.forename: Muneoki
authors.initials: M
authors.lastname: Yoh
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Cong-Qiang
authors.initials: CQ
authors.lastname: Liu
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism* / Q000494:pharmacology; D001272:Atmosphere / Q000737:chemistry*; D044002:Bryophyta / Q000187:drug effects / Q000378:metabolism*; D002681:China; D017753:Ecosystem; D058465:Nitrification / Q000187:drug effects; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes; D009930:Organic Chemicals / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D012995:Solubility
chemical_list: D064751:Ammonium Compounds; D009587:Nitrogen Isotopes; D009930:Organic Chemicals; D012987:Soil; D009584:Nitrogen