JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2022, Vol. 46 ›› Issue (2): 169-178.doi: 10.12302/j.issn.1000-2006.202104021

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Hydrogen and oxygen isotopes and hydrochemical parameters of water samples from the Sichuan Zoige Wetland Nature Reserve

SUN Rongqing1(), DONG Liqin1,*(), ZHANG Kun2,3,*(), LIU Hongqiang2, WANG Heyi1, HU Zhaoyi1   

  1. 1. School of Geography and Ecotourism, Southwest Forestry University, Kunming 650224, China
    2. School of Wetland, Southwest Forestry University, Kunming 650224, China
    3. National Plateau Wetlands Research Center, Kunming 650224, China
  • Received:2021-04-15 Accepted:2021-10-02 Online:2022-03-30 Published:2022-04-08
  • Contact: DONG Liqin,ZHANG Kun E-mail:820923639@qq.com;dongliqin2013@163.com;zhangkun@swfu.edu.cn

Abstract:

【Objective】 This study aimed to clarify the water environment characteristics and water supply relationship in the Zoige Wetland Nature Reserve, thereby providing a theoretical reference for protecting and improving this wetland and water ecosystem. 【Method】 In this study, the abundance of stable hydrogen and oxygen isotopes was measured using a liquid water/water vapor isotope analyzer, and eight ion hydrochemical characteristic indexes were measured using ion chromatography. The chemical parameters and stable hydrogen and oxygen isotopes of different water bodies (precipitation water, river water, swamp water, and underground water) in Zoige Wetland National Nature Reserve were analyzed[(δ(D) and δ(18O)], the hydrochemical types and spatial distribution characteristics of isotopes in this area were preliminarily examined, and their formation causes and environmental significance were discussed. 【Result】 (1) The main chemical type of lake water and that of the Heihe River which flows in and out of the wetlands is $HCO_{3}^{-}$-Ca (calcium bicarbonate) water. (2) The “atmospheric water line” in Ruoergai in summer is δ(D)=8.28 δ(18O)+13.86, indicating that it is less affected by the local water vapor and secondary evaporation, but evaporation is strong. Lower δ(18O) and δ(D) values reflect the characteristics of concentrated and abundant precipitation in the rainy season under the influence of marine warm and humid air masses and intense erosion of heavy isotopes along the way. The split simulation results showed that the water vapor in Zoige in summer originated from the stable westerly zone and was controlled by a westerly circulation. (3) Precipitation is the initial source of river water, swamp water, and groundwater, and the slope of river water is similar to that of swamp water, which indicates that the supply relationship between them is close and will occur most frequently. Swamp water was supplied by the tributaries of the Heihe River (Guoqu, Jingu, Amengqu, and Dena rivers), whereas the mainstream of Heihe River and the swamp were supplied through the respective intersections. 【Conclusion】 Hydrochemical characteristics of each water body in Zoige were mainly affected by water-rock interactions in the basin. The stable hydrogen and oxygen isotope characteristics of the water bodies revealed the processes of precipitation, evaporation, atmospheric circulation, and hydrological cycling in the basin.

Key words: Zoige Wetland Nature Reserve, atmospheric precipitation, hydrogen and oxygen isotopes, deuterium surplus, hydrochemical

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