| 连续筑坝河流水气界面温室气体排放通量及其影响因素 —以青海省湟水支流火烧沟为例 |
| GHG flux and its influence factors of cascaded dam area in the Huoshaogou River, China |
| 投稿时间：2018-04-10 修订日期：2020-06-05 |
| DOI：10.15928/j.1674-3075.2020.03.003 |
| 中文关键词:温室气体 排放通量 梯级筑坝河流 火烧沟 |
| 英文关键词:greenhouse gases emission flux cascaded dammed rivers Huoshaogou River |
| 基金项目:国家自然科学基金（51669028）；青海省基础研究计划（2018-ZJ-712）和中国科学院“西部青年学者”项目“青海典型城市湿地生态系统服务时空格局及其增溢机制研究”资助（201901） |
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| 中文摘要: |
| 筑坝对河流水文和水质产生巨大影响，水体温室气体排放通量和排放模式随之发生巨大变化。当前，梯级水坝对水体温室气体排放的影响过程和机制不甚清楚，相关研究亟待开展。为了探究筑坝对河流水气界面温室气体排放的影响，选取青海湟水支流火烧沟河流为研究区，采用静态箱-气相色谱实验法，于2017年对4个对连续筑坝断面水-气界面3种温室气体二氧化碳（CO2）、甲烷（CH4）、一氧化二氮（N2O）夏季排放通量和相关环境指标进行监测，分析研究河流筑坝前后的温室气体排放通量规律及其影响因素。结果显示：（1）筑坝对河流碳、氮等有机质形成滞留效应，筑坝区温室气体排放通量显著高于未筑坝区，二者排放通量平均相差4.12倍。（2）CO2、CH4和N2O排放的峰值分别出现在8月、6月和7月。（3）CO2排放通量低值-1554.19 mg/(m2?h)和高值778.84 mg/(m2?h)均在筑坝区；CH4和N2O排放低值（360 μg/(m2?h)和34.72 μg/(m2?h)）均出现在未筑坝区，而高值（分别为6163.4 μg/(m2?h)和746.7 μg/(m2?h)）均出现在筑坝区。（4）不同筑坝段水体温室气体排放通量的影响因素存在差异，CO2排放与水体电导率（Conductivity）（r=-0.914, P<0.05）、pH（r=-0.907, P<0.05）、总溶解固体（TDS）（r=-0.914, P <0.05）、盐度Sal（r=-0.926, P<0.05）和气温（Temperature）（r=0.-978, P<0.01）呈显著负相关；CH4排放通量与氧化还原电位（ORP）呈显著负相关（r=-0.968, P<0.01），与pH呈显著正相关（r=0.979, P<0.01）；N2O排放通量与电导率（Conductivity）（r=0.903, P<0.05）、总溶解固体（TDS）（r=0.904, P<0.05）、气温(T) （r=0.970, P<0.05）以及氧化还原电位（ORP）（r=0.929, P<0.05）呈显著正相关。 |
| 英文摘要: |
| Dam construction significantly alters the hydrology and water quality of rivers, leading to dramatic changes in fluxes and patterns of greenhouse gas (GHG) emissions. At present, the processes and mechanisms of the impacts produced by cascaded dams on GHG emissions remain unclear, and relevant research is urgently needed. In this case study, we investigated GHG emission patterns before and after construction of four cascaded dams on Huoshaogou River, a tributary of Huangshui River in Qinghai Province. The influence of damming the river on GHG emissions and the environmental variables affecting GHG emissions were analyzed. During the summer of 2017, emission fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were monitored across five transects located above and below the four cascaded dams on the Huoshaogou River. The emission fluxes of the three GHGs were determined using the static chamber-gas chromatography method, and three samples were collected across each transect. Hydrological and water quality parameters were simultaneously monitored to identify the primary factors influencing GHG emissions. Results show that: (1) Cascaded dams retained carbonaceous and nitrogenous organic matter and the GHG emission flux in dammed areas was 4.12 times higher than that in undammed areas. (2) The emissions of CO2, CH4 and N2O peaked, respectively, in August, June and July. (3) The lowest CO2 emission flux (-1554.19 mg / (m2?h)) and the highest flux (778.84 mg / (m2?h)) both occurred in the dammed area; the lowest flux for both CH4 (360μg / (m2?h)) and N2O (34.72μg / (m2?h)) occurred in undammed areas, while the respective peak values [6163.4μg/(m2? h) and 746.7μg/(m2?h)], occurred in dammed areas. (4) The primary influencing factors of GHG emissions varied among the gases. The CO2 emission flux was negatively correlated with water conductivity (r = -0.914, P<0.05), pH (r = -0.907, P<0.05), TDS (r = -0.914, P<0.05), salinity (r = -0.926, P<0.05) and air temperature (r = -0.978, P<0.01); CH4 emission flux was negatively correlated with ORP (r = -0.968, P<0.01) and positively correlated with pH (r = 0.979, P<0.01); N2O emission flux was positively correlated with conductivity (r = 0.903, P<0.05), TDS (r = 0.904, P<0.05)， air temperate (r=0.970, P<0.05) and ORP (r = 0.929, P<0.05). This study provides valuable insights into the complexity of factors influencing GHG emissions at the water-air interface of rivers with cascaded dams. |
| 陈玉鹏,毛旭锋,魏晓燕,苏晓虾,张 帅,刘小君.2020.连续筑坝河流水气界面温室气体排放通量及其影响因素 —以青海省湟水支流火烧沟为例[J].水生态学杂志,41(3):17-23. |
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