文献类型：期刊文献

英文题名：Contrasting Dissolved Organic Carbon Cycling in Open and Closed Karst Reservoirs Water: Evidence from Dual Carbon Isotopes (δ13C-Δ14C)

作者：Yu, Xia Liu, Hao Dai, Bingyang Liu, Xuran Mei, Zilin Ma, Chao Yang, Chengzhi Shao, Mingyu An, Yanling

第一作者：Yu, Xia;于霞

通信作者：Yu, X[1];Yu, X[2]

机构：[1]Guizhou Inst Technol, Coll Resources & Environm Engn, Guiyang 550003, Peoples R China;[2]Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550001, Peoples R China;[3]Univ Chinese Acad Sci, Coll Resources & Environm, Beijing 100049, Peoples R China

第一机构：贵州理工学院资源与环境工程学院

通信机构：corresponding author), Guizhou Inst Technol, Coll Resources & Environm Engn, Guiyang 550003, Peoples R China;corresponding author), Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550001, Peoples R China.|贵州理工学院资源与环境工程学院;贵州理工学院;

年份：2026

卷号：18

期号：12

外文期刊名：WATER

收录：;EI(收录号：20262621014747);WOS:【SCI-EXPANDED(收录号:WOS:001805219800001)】；

基金：This research was funded by the Guizhou Provincial Science and Technology Support Program, grant number QianKeHeJiChu-ZK [2024] YiBan511, and the Research Initiation Program for High-level Talents of Guizhou Institute of Technology in 2023, grant number 2023GCC082.

语种：英文

外文关键词：DOC; open-reservoir; closed-reservoir; transformation; delta C-13-Delta C-14

摘要：Reservoirs in karst regions exhibit significant carbon sink potential; however, how different reservoir types influence carbon sequestration remains poorly understood. In this study, dual carbon isotopes (delta C-13-Delta C-14) were applied to trace dissolved organic carbon (DOC) sources in an open reservoir (Aha Reservoir, AHR) and a closed reservoir (Guanshan Lake, GSL) in southwestern China, and to evaluate their carbon sequestration potential. DOC concentrations in GSL were significantly higher than those in AHR (4.14 +/- 0.28 mg/L > 3.37 +/- 0.30 mg/L) (p < 0.01), along with lower delta C-13 values (-30.34 +/- 0.51 parts per thousand < -28.18 +/- 0.31 parts per thousand) and more enriched Delta C-14 values (-6.94 +/- 11.07 parts per thousand > -93.74 +/- 6.76 parts per thousand). The delta C-13-Delta C-14 tracing revealed that plants were the primary DOC source for AHR (61 +/- 2%), whereas algae dominated DOC sources in GSL (70 +/- 2%). Inflow rivers and water retention time (WRT) likely drive differences in DOC sources and concentrations between the two reservoirs. The absence of inflow rivers and the longer WRT in GSL created favorable conditions for algal growth, resulting in substantially higher chlorophyll a (Chl.a) concentrations (103.00 +/- 29.87 mu g/L > 13.10 +/- 3.29 mu g/L) and enhanced production of autochthonous DOC through a stronger biological carbon pump (BCP) effect. These conditions further facilitate the formation and accumulation of recalcitrant DOC (RDOC), ultimately increasing DOC concentrations in GSL. Our findings highlight that closed karst reservoirs may represent important yet underappreciated carbon sinks and should receive greater attention in future carbon-sink assessments.