白龙江溶解有机碳的空间分布、来源及其控制因素探究  

Spatial Distribution,Sources and Controlling Factors of Dissolved Organic Carbon of Bailong River

作　　者：赖曼婷 钟君[1] 王万发 易沅壁 陈率 徐胜 LAI Manting;ZHONG Jun;WANG Wanfa;YI Yuanbi;CHEN Shuai;XU Sheng(Institute of Surface-Earth Science System,School of Earth Science System,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学地球系统科学学院表层地球系统科学研究院,天津300072

出　　处：《地球与环境》2021年第3期227-237,共11页Earth and Environment

基　　金：国家自然科学基金项目(41803007)。

摘　　要：流域碳循环是全球碳循环的重要组成部分,也是研究的热点,但是目前对于高原流域碳循环的认识仍然不足。白龙江流域位于青藏高原东缘,是研究高原流域碳循环的理想地区之一。为了研究白龙江流域河流水体中溶解有机碳(DOC)的空间分布特征、来源及其影响因素,我们对白龙江流域河流水体进行了系统的空间序列采样并对河流水体水温、p H、电导率(EC)、DOC浓度、DOC的稳定碳同位素组成(δ^(13)C_(DOC))及紫外-可见光吸收光谱特征等进行测试分析。分析结果显示,白龙江流域DOC浓度为0.4~4.1 mg/L,平均值为1.4 mg/L,δ^(13)C_(DOC)变化范围为-27.2‰~-26.2‰。研究结果表明白龙江源区高海拔区域DOC含量在全流域内最高,自源区至下游,DOC含量逐渐降低,干流中、下游DOC浓度值基本相同,南部DOC含量由上游支流至下游支流逐渐减少。白龙江流域DOC含量与土壤有机碳含量和α(254)之间明显的正相关性,以及δ^(13)C_(DOC)的分布范围等,均表明DOC主要来源于以C3植物为主的陆源有机质,其空间分布受到海拔(温度)和土地利用控制。Riverine carbon cycle is one of the most important components and research hotspot in studying the global carbon cycle.However,few studies focused on the riverine carbon cycle in the Tibetan Plateau.Bailong River catchment is located on the northeast edge of Tibetan Plateau,being the ideal areas to study the carbon cycle of catchment on the plateau.In order to study the spatial distribution,sources and controlling factors of dissolved organic carbon(DOC)of Bailong River catchment,the river water samples were systematically collected from the Bailong River catchment and analyzed for the temperature,p H,electrical conductivity(EC),concentration of DOC,UV optical properties andδ^(13)C of DOC.The analytical results show that the concentration of DOC is in the range of 0.4-4.1 mg/L with an average 1.4 mg/L,andδ^(13)C_(DOC)ranges from-27.2‰to-26.2‰.There is a trend of DOC spatial distribution,being high in the upstream and low in downstream,and the range of DOC concentration in the middle and lower reaches of main stream is similar,while the concentration of DOC in the southern tributary decreases gradually from the upstream to the downstream.The DOCconcentration reveals positive correlations with the soil organic carbon concentration andα(254)value.These features together withδ^(13)C_(DOC)values suggested that DOC in Bailong River catchment were mainly derived from the decomposition of terrestrial C3-type organic matter,and were controlled by the altitude(temperature)and land use.

关 键 词：溶解有机碳 陆源C3植物 空间变化 白龙江 

分 类 号：S159.2[农业科学—土壤学]