1. 1.中山大学地理科学与规划学院,广东省城市化与地理环境空间模拟重点实验室,广东 广州 510275
2.广东省地质过程与矿产资源探查重点实验室,广东 广州 510275
• 收稿日期:2018-09-03 出版日期:2018-12-10
• 通讯作者: 陶贞 E-mail:junnyinfujian@163.com;taozhen@mail.sysu.edu.cn
• 基金资助:
*国家自然科学基金项目“雅砻江下游梯级筑坝对河流生源物质性质和输出的改变机制研究”(编号:41771216)和“湿热流域源区坡面径流及壤中流驱动的碳的生物地球化学循环”(编号:41871014)资助.

### Research Advance of Changing Biogenic Substance Cycling in River Systems by Damming *

Haojun Deng 1( ), Zhen Tao 1, *( ), Quanzhou Gao 1, 2, Ling Yao 1, Yong Feng 1, Yinhua Li 1

1. 1.Geography and Planning School of Sun Yat-Sen University,Guangdong Provincial Key Laboratory for Urbanization and Geosimulation,Guangzhou 510275,China
2.Key Laboratory of Mineral Resource & Geological Processes of Guangdong Province,Guangzhou 510275,China;
• Received:2018-09-03 Online:2018-12-10 Published:2019-01-18
• Contact: Zhen Tao E-mail:junnyinfujian@163.com;taozhen@mail.sysu.edu.cn
• About author:

First author:Deng Haojun(1990-),male,Guangzhou City,Guangdong Province,Ph.D student. Research areas include riverine carbon cycle and global change. E-mail:junnyinfujian@163.com

• Supported by:
Project supported by the National Natural Science Foundation of China "Study of the altering riverine biogenic matter transformation and its export fluxes with cascade damming in the lower reach of the Yalongjiang River"(No.41771216) and "Biogeochemical cycling of carbon driven by slope runoff and subsurface flow in the headwater catchments of the humid subtropical basins"(No.41871014).

River damming transforms allotropic natural rivers into autotrophic 'impound river' (referred to "reservoir"), which changes the processes of river biogenic substance cycle and the matter properties as well as export flux from land to ocean, thus becoming one of the key problems of element biogeochemical cycle. Due to the different behavior of biogenic substances (C, N, P, Si) in biological processes, biogenic substances cycle efficiency is different, in turns, Silicon (Si)>Organic Carbon (OC)>Phosphorus (P). The migration and transformation processes of C and Si are significantly affected by phytoplankton and water retention time. Nitrogen (N) and P are mainly affected by water pH, temperature, Dissolved Oxygen (DO) and retention time. The retention efficiency of biogenic substances is shown as N>C>P>Si at the global scale. Besides, the sedimentation and burial processes of reservoirs constitute the net sink of OC in rivers. River damming alters the stoichiometric characteristics of water elements, nutrient constraints, aquatic communities composition and the coupling effect of C/N/P/Si. The stable isotopic compositions of C, N and Si can effectively trace the source, migration and transformation of biogenic matter. A combination of elements stoichiometric characteristics and stable isotopic composition could effectively indicate the change of source materials in reservoirs. With the increasing demand for clean energy, the intensity of river damming and reservoir construction will increase. Thus, a series of scientific problems including changing law of biogenic substance migration and transformation dynamic, as well as accumulation effect of ecological environment in watershed systems by river cascade damming, should need to be concerned in the biogeochemistry cycle study.

Table 1 The main forms of biogenic elements in reservoirs

Fig.1 Biogenic elements cyclic processes in reservoirs
The wide arrow refers to influx and outflux, and the dotted box is element cyclic process, all fluxes are given in units of Tg/a; (a) modified after reference[14], (b) modified after references[11,17], (c) modified after reference[12], (d) modified after reference[13]

Fig.2 Biogenic element retention efficiency in global scale reservoir [ 12 , 13 , 16 , 22 ]

Fig.3 Retention efficiency of regional reservoir
Dotted line isaverage retention rate;N data from references[ 25 , 34 ];P data from references[ 25 , 27 , 31 , 32 , 34 , 40 ];Si data from references[ 25 , 30 , 31 , 41 , 46 ]

Fig.4 The difference of elements retention efficiency [ 27 , 29 , 30 , 32 , 42 , 46 ]

Table 2 C, N and Si stable isotopic composition equation

Fig.5 The δ 13C DIC value of influx,outflux and in reservoir(data from references[ 31 , 64 , 65 ])
Different small letters indicate statistically significant differences( p<0.05)

Fig.6 The distribution of δ 30Si value in lake, river and groundwater [ 4 , 7 , 68 , 71 ]