渤海湾西岸入海河流中有机碳来源及其影响因素分析  

Sources and Influencing Factors of Organic Carbon in Rivers Running into the Western Bohai Bay

作　　者：李伟业 丁虎 韩晓昆 刘铭轩 剌伟 徐爱喆 郎赟超 LI Weiye;DING Hu;HAN Xiaokun;LIU Mingxuan;LA Wei;XU Aizhe;LANG Yunchao(Institute of Surface-Earth System Science,School of Earth System Science,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim,Tianjin 300072,China;Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station,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 [2]天津市环渤海地球关键带科学与可持续发展重点实验室,天津300072 [3]天津环渤海滨海地球关键带国家野外科学观测研究站,天津300072

出　　处：《地球与环境》2023年第2期185-195,共11页Earth and Environment

基　　金：国家自然科学基金项目(41971123);国家重点研发计划项目(2021FY101001);天津市科技局项目(21ZYJDJC00090)。

摘　　要：基于化学计量特征和不同形态碳的稳定同位素组成,探讨了渤海湾西岸具有不同闸坝控制状态和土地利用方式的两条入海河流(独流减河和捷地减河)水体中有机碳(OC)来源的时空变化及其影响因素。分析结果显示独流减河和捷地减河水体中溶解有机碳同位素组成(δ^(13)C_(DOC))的变化范围分别为-29.0‰~-24.3‰和-28.4‰~-24.2‰,而颗粒有机碳同位素组成(δ^(13)C_(POC))的变化范围分别为-36.9‰~-22.0‰和-35.7‰~-20.6‰。自河流上游到近海处,除部分点源受人为因素影响的水体外,两条河流的δ^(13)C_(DOC)值和δ^(13)C_(POC)值均呈增大趋势,且夏季比初春季节偏正。计算结果显示两条河流的有机碳主要来源于浮游生物、水生维管束植物、土壤有机质和城市污水,其相对比例分别为49%~59%、7%~11%、13%~16%和17%~27%。研究表明,河流内部的新陈代谢过程(初级生产和有机质降解)和人为活动(流域土地利用方式和闸坝控制状态等)对弱水动力条件下的两条入海河流中OC的来源和转化具有重要影响,且具有季节差异,即河流初级生产的影响在夏季强于初春季节,人为活动的影响则在初春季节强于夏季。此外,在入海口闸坝影响下,独流减河下游水体中颗粒有机碳源于浮游生物的比例在夏季和初春季节比捷地减河下游分别高9%和16%,而夏季独流减河下游水体中溶解无机碳变化也主要受控于河流初级生产,显著不同于其上游及捷地减河(主要受控于河流有机质降解)。研究结果可为深入理解弱水动力条件下入海河流OC的来源及其影响因素提供科学依据。The temporal and spatial variations of the sources of organic carbon(OC)and its influencing factors in two rivers,the Duliujian River and the Jiedijian River with different dam utilization status and land-use pattern,running into the western Bohai Bay,China,were investigated using chemometrics characters and different stable carbon isotopic compositions.The results showed that the carbon isotopic compositions of DOC(δ^(13)C_(DOC))in the Duliujian River and the Jiedijian River ranged from-29.0‰to-24.3‰and from-28.4‰to-24.2‰,respectively,while the carbon isotopic compositions of POC(δ^(13)C_(POC))in the two rivers varied from-36.9‰to-22.0‰and from-35.7‰to-20.6‰,respectively.From the upstream to the offshore,the values ofδ^(13)C_(DOC)andδ^(13)C_(POC)in the two rivers showed an upward trend,except for some water bodies affected by human factors,and they were more positive in the summer than those in the early spring.The OC in two rivers was mainly derived from plankton,aquatic vascular plants,soil organic matter and urban sewage,with relative contributions of 49%-59%、7%-11%、13%-16%and 17%-27%,respectively.This study suggested that the sources and transformations of OC in two seagoing rivers under weak hydrodynamic conditions were mainly influenced by riverine metabolic processes(e.g.primary production and organic matter degradation)and the human activities(e.g.basin land-use types and damming).They had seasonal variations,with the impacts of riverine primary production higher in summer than that in early spring,and the impacts of human activities higher in early spring than those in summer.Moreover,the relative contributions of plankton to POC in the lower reach of the Duliujian River in summer and early spring were 9%and 16%higher than that in the lower reach of the Jiedijian River due to influence of dam in the estuary.The control processes of DIC in the lower reach of the Duliujian River in summer were significantly different from its upper reach and the Jiedijian River,dominated by primary

关 键 词：有机碳 碳同位素 来源 入海河流 河口 弱水动力条件 

分 类 号：X142[环境科学与工程—环境科学]