中文关键词有色可溶性有机物(CDOM)平行因子分析法光谱吸收三维荧光太湖 英文关键词chromophoric dissolved organic matter(CDOM)parallel factor analysisspectral absorptionexcitation-emission matricesLake Taihu

作者	单位	E-mail
石玉	南京师范大学地理科学学院, 南京 210023 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	Shiycarrots@163.com
周永强	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 中国科学院大学, 北京 100049
张运林	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 中国科学院大学, 北京 100049	ylzhang@niglas.ac.cn
姚晓龙	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 中国科学院大学, 北京 100049
黄昌春	南京师范大学地理科学学院, 南京 210023

中文摘要 有色可溶性有机物（CDOM）是溶解性有机物中能强烈吸收紫外辐射及蓝光的那部分有机物，并在碳、氮、磷等生源要素生物地球化学循环中起着重要的作用.开展富营养化湖泊CDOM来源、组成结构和空间变化趋势的相关研究，有利于更好地揭示湖泊生源要素循环机制，服务于蓝藻水华控制和湖泊水质改善.本文基于对不同水文情景下太湖和周边连通的51条河流CDOM光谱吸收及三维荧光光谱测定与分析，揭示太湖CDOM光谱组成对不同水文情景的响应机制.结果表明，丰水期溶解有机碳浓度均值（8.11±1.26）mg·L^-1，显著大于枯水期均值（3.53±1.19）mg·L^-1（t-test，P<0.01），而丰水期CDOM吸收光谱斜率S_275~295均值（19.09±1.81）μm^-1，显著小于枯水期的（20.89±1.90）μm^-1（t-test，P<0.001）.平行因子分析法对CDOM荧光图谱进行解析得到3个组分，且各组分受到上游来水量的影响较大，丰水期陆源类腐殖酸的荧光强度及占总荧光强度比重较枯水期显著增大.叶绿素a与化学需氧量与陆源腐殖质和类色氨酸均呈显著正相关（P<0.01），这表明陆源生活污水及藻死亡降解产生的CDOM可能是太湖CDOM库的重要潜在来源.溶解氧浓度与3种荧光组成均呈现显著负相关（P<0.01），说明CDOM不同组分均为微生物活动的重要基质.本研究结果还发现溶解性有机碳浓度与陆源类腐殖酸组分荧光强度呈极显著线性正相关（r²=0.58，P<0.001），表明太湖溶解性有机碳主要以外源输入为主. 英文摘要 Chromophoric dissolved organic matter (CDOM) is a fraction of dissolved organic matter that can strongly absorb light in the ultraviolet and blue regions and plays an important role in the biogeochemical cycling of carbon, nitrogen, and phosphorus. Unraveling the sources, optical composition, and corresponding spatial variabilities of CDOM can improve our understanding of carbon, nitrogen, and phosphorus cycling in lakes and lake water quality management. CDOM spectral absorption and fluorescent excitation-emission matrices were measured to investigate the compositional dynamics of CDOM under different hydrological scenarios. Our results showed that the mean value of dissolved organic carbon (DOC) concentration of (8.11±1.26) mg·L^-1 in the rainy season was significantly higher than that in the dry season (3.53±1.19) mg·L^-1 (t-test, P<0.01), whereas the mean spectral slope S_275-295 of (20.89±1.90) μm^-1 in the dry season was significantly greater than that in the rainy season (19.09±1.81) μm^-1 (t-test, P<0.001). Three fluorescent components were identified using parallel factor analysis, and we further found that the dynamics of the three CDOM components were strongly influenced by hydrological conditions. Fluorescence intensity (F_max) of the terrestrial humic-rich component C2 increased with increasing water levels and rainfall. Significant negative relationships were found between all three fluorescent components and dissolved oxygen (P<0.01), suggesting that all three components served as important substrates for microbial processing. Significant positive relationships were found between the terrestrial humic-rich C2 and tryptophan-like C1 and chlorophyll-a and chemical oxygen demand, indicating that anthropogenic inputs and algal degradation contributed significantly to the CDOM pool in Lake Taihu. We further found a significant positive relationship between DOC concentration and F_max of terrestrial humic-rich C2 (r²=0.58, P<0.001), suggesting that DOC in Lake Taihu was primarily derived from allochthonous input.

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