摘要
[目的]研究喀斯特流域水土流失对水库碳汇的影响,为区域水土流失治理和科学评估喀斯特地区河流生态系统碳循环提供科学依据。[方法]基于纳雍河2014—2018年水文数据和其下游平寨水库流域2017—2018年水化学监测数据,利用回归分析、相关分析、水化学分析方法,研究水土流失对水库碳汇的影响。[结果]①2014—2018年,干流纳雍河流量1.15×10^(9)~1.66×10^(9) m^(3)/a,泥沙通量2.54×10^(5)~1.23×10^(6) t/a。泥沙通量和流量在年际间无相关性,在月时间尺度上呈极显著正相关,短时强降雨是流域发生水土流失的主要原因之一,流域内春夏季水土流失剧烈,秋冬季减弱。②平寨水库Ca^(2+)和HCO^(-)_(3)为主要阴阳离子,来源于碳酸盐岩风化。SO^(2-)_(4)是第二大阴离子,参与水库30.30%~59.70%的碳酸盐岩风化,水库水化学类型秋冬季为HCO^(-)_(3)-Ca型,春夏季主要为HCO^(-)_(3)-SO^(2-)_(4)-Ca型。③平寨水库水库二氧化碳分压具有时空异质性,表现为:冬季>秋季>春季>夏季,秋冬季为碳源,春夏季为碳汇。[结论]平寨水库流域水土流失与水库碳汇效应具有相同的周期性季节变化,水土流失影响水库水化学组成,减弱水库碳汇效应。
[Objective]The impacts of soil erosion on reservoir carbon sinks in karst watersheds were studied,in order to provide scientific basis for regional soil erosion control and scientific assessment of carbon cycle in river ecosystems in karst areas.[Methods]Based on hydrological data of Nayong River from 2014 to 2018 and water chemistry monitoring data of Pingzhai Reservoir at the downstream from 2017 to 2018,regression analysis,correlation analysis,and water chemistry analysis were used to study the effects of soil erosion on reservoir carbon sinks.[Results]①During period from 2014 to 2018,the flow of the Nayong River ranged from 1.151 to 1.663 billion m^(3)/a,and sediment flux ranged from 25.36 to 1.2247 million t/a.Sediment flux and water flow were not correlated between years but showed a highly significant positive correlation on the monthly time scale.The short-time intense rainfall was one of the main reasons for the occurrence of soil erosion in the watershed.The erosion was intense in spring and summer and weak in autumn and winter.②Ca^(2+)and HCO^(-)_(3) were the main anions in Pingzhai Reservoir,which came from carbonate rock weathering.SO^(2-)_(4) was the second most important anion,participating in 30.30%~59.70%of carbonate rock weathering in the reservoir.Reservoir water chemistry type was HCO-3-Ca type in autumn and winter,and mainly HCO^(-)_(3)-SO^(2-)_(4)-Ca type in spring and summer.③The partial pressure of carbon dioxide in the reservoir of Pingzhai Reservoir showed spatial and temporal heterogeneity as:winter>autumn>spring>summer,which were showed as carbon sources during autumn and winter,and as carbon sinks while spring and summer.[Conclusion]Soil erosion and reservoir carbon sink effect in Pingzhai Reservoir basin have the same periodic seasonal changes,soil erosion affects reservoir water chemistry and weakens reservoir carbon sink effect.
作者
王翠
周忠发
李永柳
张勇荣
Wang Cui;Zhou Zhongfa;Li Yongliu;Zhang Yongrong(School of Geography and Environmental Science/Karst Institute, Guizhou Normal University, Guiyang, Guizhou 550001, China;The State Key Laboratory Incubation Base for Karst Mountain Ecological Environment of Guizhou Province, Guiyang, Guizhou 550001, China)
出处
《水土保持通报》
CSCD
北大核心
2021年第6期1-7,共7页
Bulletin of Soil and Water Conservation
基金
国家自然科学基金项目“喀斯特筑坝河流水安全与调控对策”(U1612441)
贵州省科学技术基金项目(黔科合平台人才[2016]5674)
贵州省研究生科研项目〔黔教合YJSCXJH(2020)110〕。
关键词
喀斯特
水土流失
水化学
水库碳汇
karst
soil erosion
hydrochemistry
reservoir carbon sink