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三峡水库干-支流作用下生态水文过程的氢氧同位素示踪

叶振亚1,王雨春1,2*,胡明明2,汪国骏1,梁顺田2,王启文2,高继军2,刘德富1#br#   

  1. 1中国水利水电科学研究院水环境研究所, 北京 100038;2流域水循环模拟与调控国家重点实验室, 北京 100038; 3三峡大学, 湖北宜昌 443000)
  • 出版日期:2017-08-10 发布日期:2017-08-10

Hydrogen and oxygen stable isotope tracing of eco-hydrological processes in water bodies mixing the mainstream and a tributary of the Three Gorges Reservoir.

YE Zhen-ya1, WANG Yu-chun1,2*, HU Ming-ming2, WANG Guo-jun1, LIANG Shun-tian2, WANG Qi-wen2, GAO Ji-jun2, LIU De-fu1#br#   

  1. (1China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 2State Key Laboratory of Water Cycle Modeling and Controlling, Beijing 100038, China; 3China Three Gorges University, Yichang 443000, Hubei, China).
  • Online:2017-08-10 Published:2017-08-10

摘要: 三峡工程蓄水运行后,三峡库区支流不同区域的水动力状态存在差异。为了阐明支流库湾的生态水文过程,本文以库腹支流(朱衣河)为研究对象,应用同位素示踪技术,分析了2015年朱衣河及其毗邻长江干流的氢氧同位素时空变化特征,并揭示了干支流、源头支流等端元混合过程中的水团特性。结果表明:(1)朱衣河库湾回水区河水的δD组成范围为-84.1‰~-54.4‰,δ18O组成范围为-11.71‰~-8.13‰,与毗邻的干流水体接近,明显低于支流源头来水(δD为-49.6‰~-46.1‰,δ18O为-7.61‰~-7.19‰)。(2)运用二元线性混合模型估算出长江干流对朱衣河回水区的水量补给率约为95%,库湾水体主要受干流倒灌作用的支配。(3)长江干流水体对朱衣河库湾的倒灌模式主要为:汛前消落期和枯水期集中在河口中层;汛期和蓄水期则集中在河口中上层。氢氧同位素示踪技术在分析库湾受干流倒灌模式上具有较好的适用性。(4)长江流域位于季风性气候区域,雨季影响朱衣河库湾氢氧同位素组成的主要因素排序为:干流倒灌作用>降水>同位素分馏作用,不同于旱季(干流倒灌作用>同位素分馏作用>降水)。

关键词: 氮肥利用率, 干物质积累量, 氮肥最大效率期, 苹果, 氮积累量

Abstract: There exists heterogeneity in water dynamics in different areas of the Three Gorges Reservoir tributaries after impoundment. In order to illustrate the processes of ecological hydrology in tributaries, a tributary (Zhuyi Bay) was chosen to analyze the spatiotemporal characteristics of hydrogen and oxygen isotopic compositions using isotope tracing technique. The water mass characteristics of endmember mixing process of the mainstreamtributary and sourcetributary was also revealed. The results showed that: (1) In backwater area of Zhuyi Bay, the δD values ranged from -84.1‰ to -54.4‰, and δ18O from -11.71‰ to -8.13‰. These values were respectively similar to those of adjacent water body in mainstream, while obviously less than those in source water of the tributary (δD: -49.6‰ to -46.1‰; δ18O: -7.61‰ to -7.19‰). (2) The rate of water recharge of the mainstream of Yangtze River to the backwater area of Zhuyi Bay was approximately 95% using binary linear mixed model. This value indicated that bay water was mainly affected by the backward flowing from the mainstream to the tributary. (3) The backward flowing from the mainstream of Yangtze River to Zhuyi Bay occurred in the middle layer of Zhuyi Bay estuary during preflood hydrofluctuation period and dry period, whereas in the uppermiddle layers during flood period and storage period. Hydrogen and oxygen isotope tracing technique has relatively good applicability in analyzing the mode of backward flowing. (4) Yangtze River locates in monsoon climate areas, and the main factors affecting hydrogen and oxygen isotope compositions of Zhuyi Bay in rainy season could be ordered in significance as: backward flowing > rain > isotope fractionation. However, this order changed as backward flowing > isotope fractionation > rain in dry season.

Key words: dry matter accumulation, fertilizer N maximum efficiency period, fertilizer N utilization, N accumulation, apple