贵州草海颗粒物和沉积物有机碳氮同位素特征及来源研究  

Organic Carbon and Nitrogen Isotope Characteristics and Source Analysis of Particulate Matter and Sediment in Caohai Lake,Guizhou Province

作　　者：廖敏 姜鑫[1] 黄先飞[1] 夏品华[1] LIAO Min;JIANG Xin;HUANG Xian-fei;XIA Pin-hua(Key Laboratory of Mountain Information System and Ecological Environment Protection of Guizhou Province,Guizhou Normal University,Guiyang 550001,P.R.China)

机构地区：[1]贵州师范大学贵州省山地环境信息系统与生态环境保护重点实验室,贵州贵阳550001

出　　处：《水生态学杂志》2024年第4期40-47,共8页Journal of Hydroecology

基　　金：贵州省科技计划项目(黔科合支撑一般[2023]216);国家自然科学基金(32360288)。

摘　　要：探究湖泊有机质来源,为从源头上控制草海营养盐负荷提供参考。在草海湖泊及入湖河流上设置13个采样点,于2023年3月采集并测定湖泊和河流中颗粒物和沉积物的有机碳同位素(δ^(13)C)、有机氮同位素(δ^(15)N)、C/N及总有机碳(POC、TOC)和总氮(PON、TON),结合MixSIAR同位素模型分析颗粒物和沉积物的有机碳氮来源及贡献率。结果表明:颗粒物δ^(13)C为-27.56‰~-23.64‰,δ^(15)N为3.12‰~10.93‰,颗粒物有机碳主要来源于大气沉降(21.1%)和水生植物(20.7%),氮来源主要为土壤有机质(25.6%)和水生植物(25.3%);沉积物δ^(13)C为-28.18‰~-20.53‰,δ^(15)N为1.70‰~6.58‰,沉积物有机碳主要来源于大气沉降(34.4%)和水生植物(33%),氮主要来源于化肥(24%)。颗粒物和沉积物之间有机氮来源的差异反映出土壤有机质和水生植物来源的有机氮易降解,而化肥来源的氮则易沉积。Caohai Lake is a typical karst lake on the Guizhou plateau,with a fragile ecological environment.Since 2020,Caohai Lake has transitioned from a grass-type lake to an algae-type lake,and water quality has deteriorated as aquatic vegetation declined.Identifying the sources of organic matter in the water and sediments of lakes is crucial for understanding the nutrient cycle and controlling eutrophication.In this study,we analyzed the total organic carbon(POC,TOC)and total nitrogen(PON,TON)of the particulate matter and sediments in the Caohai Lake and its inflow rivers.For source identification,the ratios of carbon isotopes(δ^(13)C)and nitrogen isotopes(δ^(15)N)and the ratio of carbon to nitrogen(C/N)of particulate matter and sediments were determined.The resulting data was fed into the MixSIAR isotope model,allowing the organic carbon and nitrogen sources and their contributions to suspended particulate matter and sediments to be qualitatively and quantitatively determined.In March 2023(dry season),water and sediment samples were collected at 13 sampling sites in Caohai Lake(L1-L9)and its four main tributaries(R1-R4)for analysis.The percentage content of POC and PON were 1.79%-25.72%and 0.26%-2.98%in the particulate matter and the percentage content of TOC and TON were(1.50%-27.58%)and(0.16%-1.82%)in the sediment,respectively.Theδ^(13)C andδ^(15)N ranges of the particulate matter were from-27.56‰to-23.64‰and from 3.12‰to 10.93‰,and theδ^(13)C andδ^(15)N of the sediments ranged from-28.18‰to-20.53‰and 1.70‰to 6.58‰,respectively.Theδ^(13)C andδ^(15)N values of the particulate matter and sediment both displayed significant differences and there were no clear correlations between Caohai Lake and the four tributaries,indicating that the lake and its tributaries have different sources of organic matter,and that the organic matter in Caohai Lake is not affected by inflow rivers.The primary sources of particulate organic carbon to the lake are atmospheric deposition(21.1%)and aquatic plants(20.7%),an

关 键 词：颗粒物 沉积物 MixSIAR同位素模型 有机碳氮来源 草海 

分 类 号：X142[环境科学与工程—环境科学] X524