Kato Tomomichi, Yamada Keita, Tang Yanhong, Yoshida Naohiro, Wada Eitaro
a Research Institute for Global Change , Japan Agency for Marine-Earth Science and Technology , Yokohama , Kanagawa , Japan.
b Research Faculty of Agriculture , Hokkaido University , Sapporo , Hokkaido , Japan.
Isotopes Environ Health Stud. 2017 Dec;53(6):597-609. doi: 10.1080/10256016.2017.1326916. Epub 2017 May 25.
On the Qinghai-Tibetan Plateau, isotopic signatures in soil-atmosphere CH fluxes were investigated in nine grasslands and three wetlands. In the grasslands, the fractionation factor for soil CH uptake, α, was much smaller than the usually reported value of 0.9975-1.0095. Stepwise multiple variation analysis indicates that α is higher for higher soil water contents but is lower for higher C/N ratios of soil surface biomass. In the three wetlands, the soil-emitted δC-CH was similar (-55.3 ± 5.5 ‰ and -53.0 ± 5.5 ‰) in two bogs separated by >1000 km but was lower (-63.4 ± 6.3 ‰) in a marsh. Environmental factors related to intrasite variations in soil-emitted δC-CH include the soil C/N ratio, oxidation-reduction potential, soil C concentration and soil water contents. Geographical isotopic surveys revealed environmental constraints on the CH consumption pathways in grasslands and the biome type-specific consistency in CH production pathways in wetlands.
在青藏高原，研究人员对9片草地和3片湿地土壤 - 大气CH通量的同位素特征进行了调查。在草地中，土壤CH吸收的分馏因子α远小于通常报道的0.9975 - 1.0095的值。逐步多元方差分析表明，土壤含水量越高，α值越高，但土壤表层生物量的C/N比越高，α值越低。在3片湿地中，被超过1000公里隔开的两片沼泽地土壤排放的δC-CH相似（-55.3±5.5‰和-53.0±5.5‰），但在一片沼泽中较低（-63.4±6.3‰）。与土壤排放δC-CH的位点内变化相关的环境因素包括土壤C/N比、氧化还原电位、土壤C浓度和土壤含水量。地理同位素调查揭示了草地中CH消耗途径的环境限制以及湿地中CH产生途径的生物群落类型特异性一致性。
