鄱阳湖丰枯情景对有色可溶性有机物生物可利用性及收支平衡的影响  

Influences of Hydrological Scenarios on the Bioavailability, Fate, and Balance of Chromophoric Dissolved Organic Matter in Lake Poyang

作　　者：郭燕妮 姚晓龙[1] 陈慧敏 俞晓琴 李宇阳 朱俊羽 韩龙飞 周蕾[1,3] 周永强 GUO Yan-ni;YAO Xiao-long;CHEN Hui-min;YU Xiao-qin;LI Yu-yang;ZHU Jun-yu;HAN Long-fei;ZHOU Lei;ZHOU Yong-qiang(State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China;School of Geographic Science,Hunan Normal University,Changsha 410081,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]湖南师范大学地理科学学院,长沙410081 [3]中国科学院大学,北京100049

出　　处：《环境科学》2022年第2期837-846,共10页Environmental Science

基　　金：国家自然科学基金项目(41807362,41930760);中国科学院青年促进会项目(2021312);江苏省自然科学基金项目(BK20181104)。

摘　　要：鄱阳湖水力连通特征季节差异显著,研究不同水文情景下湖泊调蓄对有色可溶性有机物(CDOM)来源组成、生物可利用性和碳收支平衡的影响对揭示通江湖泊碳循环、水体有机物迁移转化和水资源管理具有重要意义.通过平行因子分析法对鄱阳湖CDOM三维荧光光谱解析得到3个荧光组分,分别为类腐殖质(C1)、类色氨酸(C2)和类酪氨酸(C3).生物培养前后CDOM吸收系数(a254)和陆源类腐殖质(C1)均表现为丰水期显著高于枯水期(t-test,P<0.01),表明陆源类腐殖质(C1)是该湖丰水期CDOM的主要来源.枯水期类蛋白组分占CDOM荧光组分强度总和的81.7%,表明枯水期可能与周边生产生活废水排放有关.类腐殖酸(C1)和DOC的生物可利用性在枯水期达到最大,分别为14.0%和43.2%,这与湖泊枯水季节湖床干涸,上游及周边人类活动排入废水很少受到湖水稀释密切相关.类蛋白组分的生物有效性在丰水期略高于枯水期,并无显著差异.生物可利用对应成分%ΔC1在丰、枯水期均呈现出从南部河口区向北部出湖口递减的趋势,表明类腐殖质(C1)的生物可利用性随CDOM迁移而降低.在枯水期和丰水期,鄱阳湖均表现为DOC源,源通量分别为14.0×10^(3) t·月^(-1)和1.4×10^(3) t·月^(-1),而该湖CDOM通量在枯水期和丰水期分别表现为源和弱汇,对应通量分别为9.3×1010 m^(3)·(m·月)^(-1)和1.1×1010 m^(3)·(m·月)^(-1),表明枯水期湖泊主要向下游排放DOC和CDOM,而丰水季节长江干流水位雍高湖水宣泄不畅,输入的少部分CDOM可被降解为无机碳、氮和磷等营养盐,影响湖泊碳循环和富营养化进程.Lake Poyang has significant differences in hydrological characteristics between the flood and dry seasons.Unraveling the optical composition,bioavailability,fate,and balance of chromophoric dissolved organic matter(CDOM)and organic carbon fluxes in Lake Poyang under different hydrological conditions can help provide advanced schemes on carbon cycling,the transfer and transformation of organic matter,and water resource management of the lake.Three fluorescent components,including a humic-like(C1),a tryptophan-like(C2),and a tyrosine-like(C3)component,were obtained using three-dimensional fluorescence spectroscopy coupled with parallel factor analysis.Prior to and after 28 days of laboratory biodegradation,the means of a254 and the terrestrial humic-like(C1)component in the flood season were both significantly higher than that in the dry season(t-test,P<0.01),indicating that the terrestrial humic-like(C1)component contributed importantly to the CDOM pool.The contribution percentages of protein-like components in the dry season were 81.7%of the summed fluorescent components of CDOM,indicating that there might be discharge of domestic wastewater from areas surrounding the lake in the dry season.The bioavailabilities of the humic-like(C1)component and DOC were 14.0%and 43.2%,respectively,in the dry season.This can be explained by a declined-dilution effect in the lake during the dry rather than in the flood season.We observed no significant difference in the bioavailability of protein-like components under different hydrological conditions.The bioavailability of C1(i.e.,%ΔC1)showed a decreasing trend from the southern inflowing river mouths to the downstream northern outlet at Hukou in both the flood and dry seasons,indicating that the bioavailability of the C1 decreased following the migration of CDOM in the lake.In the dry season and flood season,Lake Poyang was the source of DOC with fluxes of 14.0×10^(3) t·mon^(-1) and 1.4×10^(3) t·mon^(-1),respectively,whereas CDOM fluxes in corresponding periods were the so

关 键 词：鄱阳湖 有色可溶性有机物(CDOM) 生物可利用性 平行因子分析(PARAFAC) 三维荧光(EEMs) 

分 类 号：X524[环境科学与工程—环境工程]