流溪河水库流域碳氮营养盐浓度的时空变化特征及其影响因素  

Spatial-temporal Variation of Carbon and Nitrogen Nutrients Concentrations and Its Influencing Factors in Liuxi River Reservoir Basin

作　　者：牛香豫 唐国平 顾慧 陈桃 陈晓桦 NIU Xiangyu;TANG Guoping;GU Hui;CHEN Tao;CHEN Xiaohua(School of Geography and Planning, Sun Yat-sen University, Guangzhou 510275)

机构地区：[1]中山大学地理科学与规划学院,广州510275

出　　处：《水土保持学报》2022年第2期352-360,共9页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(42171025)。

摘　　要：流溪河水库流域是亚热带典型的山地河源区,研究此流域的碳氮营养盐浓度时空变化特征及其影响因素对揭示亚热带流域生物地球化学循环与保障水资源供给具有重要意义。基于地形、气象、土地利用、土壤和实地采样获得的水质数据,采用相关分析及Elastic Net回归分析法,探讨了流溪河水库流域溪流碳氮营养盐浓度的时空变化特征及其影响因素。结果表明:(1)从时间上看,枯水期各采样点溪流碳氮营养盐浓度总体变化不大,但空间差异明显,其中NO_(3)^(-)与NH_(4)^(+)浓度具有强相关性。(2)流域坡度大小是引起不同溪流碳氮营养盐浓度存在差异的重要因子,且三级以上坡度对碳氮营养盐浓度变化产生显著的正面影响。(3)流域平均相对湿度也显著影响溪流碳氮营养盐的浓度。流域相对湿度越大,溪流的溶解有机碳浓度相对较高,但氮营养物浓度相对较低;同DOC相比,NO_(3)^(-)和NH_(4)^(+)对气象条件变化敏感度较低。(4)土地利用如建成区面积占比等人类活动显著影响碳氮营养盐的浓度,表现为建成区面积占比与DOC浓度呈负相关关系。此外,森林覆盖度增大会提高溪流DOC和NO_(3)^(-)的浓度,但对NH_(4)^(+)浓度的影响不显著。(5)土壤类型也影响流域碳氮营养盐的浓度,简育低活性强酸土对NO_(3)^(-)浓度产生正面影响,人为堆积土对NH_(4)^(+)浓度产生正面影响。研究结果可为流域水资源保护和了解碳氮营养物浓度的变化及影响因素提供有益信息。The Liuxi River reservoir basin is a typical subtropical mountain basin,and it is of great significance to study the changing characteristics of carbon and nitrogen nutrients concentrations in this basin and its influencing factors to reveal the biogeochemical cycle of subtropical basin.Based on the field sampling of water quality,landscape topography,meteorology,land use as well as soil data,this paper explored the spatial-temporal changing characteristics and the influencing factors of the carbon and nitrogen nutrients concentrations in streams located in the Liuxi River Reservoir basin,using correlation and Elastic Net regression analysis.The results showed that:(1)The temporal trend of carbon and nitrogen nutrients concentrations in streams was relatively stable during dry period,whereas the spatial variation was obvious.(2)The slope of sub-basin was an important environmental factor that caused the changes of carbon and nitrogen nutrients concentrations in different streams,and the slope beyond 6°had a significant positive effect on the change of carbon and nitrogen nutrients concentrations.(3)The average relative humidity of the basin also significantly affected the concentrations of carbon and nitrogen nutrients in streams.The greater the relative humidity of the basin was,the higher the concentration of carbon nutrients in the streams would be,but the concentration of nitrogen nutrients would be relatively low.Compared witth the DOC,the NH_(4)^(+)and NO_(3)^(-)concentrations in streams were less sensitive to the weather conditions.(4)The land use,such as the proportion of the built-up area and other human activities,significantly affected the concentrations of carbon and nitrogen nutrients,as shown by a negative correlation between the built-up area and the DOC concentration.The increased forest cover could enhance the DOC and NO_(3)^(-)concentrations in streams,but had no significant effect on the NH_(4)^(+)concentration.(5)The different soil types also affected the concentrations of carbon and nitrogen

关 键 词：碳氮营养物 弹性网络回归 人类活动 土地利用 生物地球化学循环 

分 类 号：X143[环境科学与工程—环境科学] X524