土地利用对典型喀斯特河流溶解性有机质的直接和间接影响  

Direct and Indirect Effects of Land Use on Dissolved Organic Matter in a Typical Karst River

作　　者：张柳柳 刘睿[1,2] 郑达燕[1,2] 郑财贵 张静 ZHANG Liu-liu;LIU Rui;ZHENG Da-yan;ZHENG Cai-gui;ZHANG Jing(School of Geography and Tourism,Chongqing Normal University,Chongqing 401331,China;Key Laboratory of GIS Application Research,Chongqing Normal University,Chongqing 401331,China;Chongqing Planning and Natural Resources Survey and Monitoring Institute,Chongqing 401121,China;Key Laboratory of Monitoring,Evaluation and Early Warning of Territorial Spatial Planning Implementation,Ministry of Natural Resources,Chongqing Planning and Natural Resources Bureau,Chongqing 401147,China)

机构地区：[1]重庆师范大学地理与旅游学院,重庆401331 [2]重庆师范大学GIS应用研究重点实验室,重庆401331 [3]重庆市规划和自然资源调查监测院,重庆401121 [4]重庆市规划和自然资源局自然资源部国土空间规划监测评估预警重点实验室,重庆401147

出　　处：《环境科学》2023年第10期5511-5523,共13页Environmental Science

基　　金：国家自然科学基金项目(41801063);重庆市自然科学基金项目(cstc2020jcyj-msxmX0549);重庆市教委科学技术研究计划项目(KJQN202200517);重庆师范大学基金项目(20XLB022)。

摘　　要：土地利用可向河流直接输送陆源有机质直接影响河流溶解性有机质(DOM)丰度,也可通过增强河流营养负荷间接加强DOM的本地生产.研究基于紫外-可见光吸收光谱(UV-VIS)和三维荧光-平行因子分析(EEM-PARAFAC)技术研究雨季(7月)芙蓉江河流DOM组分特征和空间分布,并采用相关分析和偏最小二乘路径模型(PLS-PM)辨析和量化多尺度下土地利用对DOM的直接和间接影响.结果表明,土地利用对DOM的直接影响普遍强于间接影响.不同DOM组分对水体营养状况和土地利用的响应各异,溶解性有机碳(DOC)和有色溶解性有机质(CDOM)更易受水体营养状况影响,荧光溶解性有机质(FDOM)则对土地利用更为敏感.土地利用对DOC和CDOM的直接影响强度随空间尺度略有波动,但总影响强度无明显的空间尺度差异,对FDOM的直接影响强度在河段500 m缓冲区尺度最大,且随尺度增大而降低.旱地、城镇用地、其它建设用地、斑块密度(PD)、边缘密度(ED)和香农多样性指数(SHDI)为增加河流DOM丰度的典型土地利用指标,水田、灌木林、最大斑块指数(LPI)和聚合度指数(AI)为有效减少DOM丰度的典型土地利用指标.总氮(TN)、硝态氮(NO_(3)^(-)-N)和溶解性总磷(DTP)与土地利用和DOM密切相关,即氮、磷元素在"土地利用-河流DOM"中有着重要的"中介"作用.FDOM可作为衡量近河段土地利用直接向河流输入陆源有机质强弱的指示参数.Land use can directly affect the abundance of riverine dissolved organic matter(DOM)by transporting terrestrial organic matter to rivers and can also indirectly enhance local production of DOM by increasing riverine nutrient loading.This study investigated the characteristics and spatial distribution of DOM components in the Furong River during the rainy season(July)using ultraviolet-visible light absorption spectroscopy(UV-VIS)and three-dimensional excitation emission matrix fluorescence spectroscopy-parallel factor analysis(EEM-PARAFAC)techniques.Furthermore,correlation analysis and the partial least squares path model(PLS-PM)were used to identify and quantify the direct and indirect impacts of land use on DOM at multiple scales.The results revealed that:①the direct effects of land use on DOM were generally stronger than the indirect effects.②The responses of different DOM components to riverine nutrient status and land use varied,with dissolved organic carbon(DOC)and colored dissolved organic matter(CDOM)components being more susceptible to riverine nutrient status and fluorescent dissolved organic matter(FDOM)being more sensitive to land use.③The direct impact intensity of land use on DOC and CDOM fluctuated slightly with the spatial scale,but the total impact intensity had no visible spatial scale difference,and the direct impact intensity on the FDOM component decreased with the increase in spatial scale.④Dryland,urban and other construction land,patch density(PD),edge density(ED),and Shannon's diversity index(SHDI)were typical land use metrics that exacerbated DOM abundance,whereas paddy field,shrubland,largest patch index(LPI),and aggregation index(AI)were typical land use metrics that effectively mitigated DOM abundance.Total nitrogen(TN),nitrate nitrogen(NO_(3)^(-)-N),and dissolved total phosphorus(DTP)were water quality parameters that were significantly affected by land use and were closely related to DOM components,that is,nitrogen and phosphorus played an important"intermediary"role in"land

关 键 词：溶解性有机质(DOM) 土地利用 偏最小二乘路径模型(PLS-PM) 直接和间接影响 芙蓉江 

分 类 号：X522[环境科学与工程—环境工程]