Water–Air Interface Greenhouse Gas Emissions (CO2, CH4, and N2O) Emissions Were Amplified by Continuous Dams in an Urban River in Qinghai–Tibet Plateau, China

Dengxing Yang,Xiaoyan Wei,Jianhai Ma,Zhifa Zhang,Yaqing Tao,Xufeng Mao

doi:10.3390/w12030759

Dengxing Yang, Xiaoyan Wei + Show 4 more

Open Access

https://doi.org/10.3390/w12030759

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Journal: Water	Publication Date: Mar 10, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Shaanxi Normal University, Qinghai Normal University

Abstract

Continuous dams may lead to great variation in greenhouse gas (GHG) emissions from rivers, which contribute more uncertainty to regional carbon balance. This study is among the first to determine water–air interface GHGs (CO2, CH4, and N2O) in a river with continuous dams in plateau city. Combined static-chamber gas and meteorological chromatography were utilized to monitor the GHGs emission flux at the water–air interface within four continuous dams in the Huoshaogou River in the Qinghai–Tibet Plateau, China. A variation coefficient (VC) and amplification coefficient (AC) were designed to detect the influence of continuous dams on GHG emissions. Results indicate that (1) cascade dams presented an amplifying effect on GHGs emissions from the water-air interface. The VCs of three types of GHGs are 3.7–6.7 times higher than those of the undammed area. The ACs of three types of GHGs are 2.7–4.1 times larger than environmental factors; (2) the average GHG emission fluxes in some dams are higher than that of the first dam, indicating that an amplifying effect may have been accumulated by some continuous dams; (3) EC, pH, Twater, Tair and TDS are found to be principle influencing factors of GHG emission and light intensity, Twater, TOC (plant), TN (sediment) and TOC (sediment) are found to be associated with accumulative changes in GHG emission.

Highlights

It has been reported that there are more than 100 million big and small dams around the world, which are mainly constructed to control flooding, generate electricity, and are visually appealing to human beings [1,2]
This study focused on the effects of continuous damming on the emissions of greenhouse gas (GHG) of the Huoshaogou River in the Qinghai–Tibet Plateau
The main factors influencing GHG emissions were extracted with respect to hydrology and water quality, and other characteristics

Summary

Introduction

It has been reported that there are more than 100 million big and small dams around the world, which are mainly constructed to control flooding, generate electricity, and are visually appealing to human beings [1,2]. They alter the hydrology and aquatic ecosystems, thereby having a significant impact on river ecosystems [3,4]. The nutrient-rich sediment creates an environment facilitating the growth of aquatic- and micro-organisms, and the metabolic rate may be accelerated, resulting in an increase in emissions of GHGs such as CO2 and CH4 [11,12]

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Discussion

Conclusion