Vol18 No.4: 878-890
【Title】Carbon isotope variationsof modern soils in the eastern margin of the Tibetan Plateau and their controlling factors
【Author】QI Lin1,2; QIAO Yan-song1,2*; LIU Zong-xiu1,2; PENG Sha-sha3; CHENG Yu4; WANG Yan2; ZHANG Xu-jiao5; TIAN Ming-zhong5; YANG Shuai-bin2; BAI Wen-bin5
【Addresses】1 Key Laboratory of Neotectonic Movement & Geohazard, Chinese Academy of Geological Sciences, Beijing 100081, China; 2 Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China; 3 Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; 4 Institute of Geological Survey of Jiangsu Province, Nanjing 210018, China; 5 School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
【Corresponding author】QIAO Yan-song
【Citation】Qi L, Qiao YS, Liu ZX, et al. (2021) Carbon isotope variations of modern soils in the eastern margin of the Tibetan Plateau and their controlling factors. Journal of Mountain Science 18(4). https://doi.org/10.1007/s11629-019-5863-3
【Abstract】The marginal areas of the Tibetan Plateau havegreat vertical altitude gradient and abundant vegetation, they are therefore the ideal places for investigating the relationships amongcarbon isotope composition (δ13C) of modern soils, vegetation and environmentalfactors, which would be very useful for thereconstructions of both paleovegetation and paleoclimate. In this paper, modern soilsamplescollected in different vegetation vertical zones along 4 km elevation gradient in the eastern margin of the Tibetan Plateauwere analyzedfor theircarbon isotope composition. The results show that the modern soils in different vegetation vertical zones show apparent difference of δ13C values, which getheavier in the sequence ofmixed evergreen and deciduous broad-leaved forest (-27.28‰ on average), evergreen broad-leaved forest (-27.25‰), subalpine shrub-meadow (-25.81‰), subalpine coniferous forest (-25.81‰), alpine bush-meadow (-25.16‰),and drought-enduring shrub (-24.07‰).1800 mand3500 m are two critical points forthe δ13C valueswith respect to altitude.Specifically, the δ13C values decrease with increasing altitude below both points while increasingwith increasing altitude above both points.Furtheranalyses indicatethatthe declining δ13C valuesaremainly controlled by the decreasing proportion of C4 plantswith elevation and the increasing δ13Cvalues are attributed to the plant physic-morphological adaptation to the alpine environment.In the absence of drought stress, temperature is the main controllingfactor for the carbon isotopic variations with altitude gradient.
【Keywords】Soil δ13C; C4 plant; Altitude; Vertical zonality