• 关键词：有色溶解有机物(CDOM)  三维荧光光谱  荧光团  积分荧光  九龙江口

• 基金项目：国家自然科学基金(No.40776041,40676046,40106007)

• 韩宇超
• 1. 北京师范大学环境学院, 北京 100875; 2. 厦门大学近海海洋环境科学国家重点实验室, 厦门 361005

• 郭卫东
• 厦门大学近海海洋环境科学国家重点实验室, 厦门 361005

• 摘要：采用三维荧光光谱(EEMs)技术,结合EEMs全光谱及特定光谱区荧光强度积分的方法,研究了九龙江口有色溶解有机物(CDOM)入海过程中在来源及性质上发生的变化特征,并分析了河口外高盐度海区CDOM各荧光组分的垂直分布特征.结果表明,九龙江河口区CDOM含有类腐殖质荧光峰A、C、M以及类色氨酸荧光峰T1、T2,而在口外高盐度海区还观测到类酪氨酸荧光峰B.EEMs总荧光强度积分值(TOT)可作为表征河口区CDOM浓度的一个良好指标,且优于常规的单点荧光法.从河端至外海,TOT及CDOM各荧光团的荧光强度积分值(IFI)不断减小,表明陆源输入为河口区CDOM的主要来源.而在河口高盐度海区,类蛋白质荧光团T1、T2在TOT中的比例不断升高,显示了生物活动的贡献.九龙江口外高盐度站位中层各荧光峰尤其是类蛋白质荧光峰(T1、T2、B)强度高于表、底层,反映了CDOM光化学反应和生物作用的共同影响.沉积物间隙水中C峰极其微弱,而类蛋白质荧光峰T1、T2、B却非常强烈,反映了沉积物中微生物活动对蛋白质的显著降解作用.

• Abstract：Fluorescence Excitation Emission Matrix Spectroscopy(EEMs) was used to characterize the change in source and properties of Chromophoric Dissolved Organic Mater(CDOM) during the mixing of freshwater and seawater in the Jiulong River Estuary.Both total integrated fluorescence intensity(TOT) and the Integrated Fluorescence Intensity(IFI) for every fluorophore were calculated in EEMs of CDOM.The vertical distribution of fluorescent CDOMcomponents was also studied for a high salinity station out of the estuary(Sstation).Five fluorophores were found in CDOMfrom the Jiulong River estuary,including three humic-like fluorescence peaks(A,C,M) and two tryptophan-like fluorescence peaks(T1,T2),while an extra tyrosine-like peak was found in CDOMsamples from the Sstation.The total integrated fluorescence intensity(TOT) of EEMs can be used as a good index for CDOMconcentration,which is better than the traditional one-point fluorescence method.TOTand IFIof all fluorescent peaks decreased along the salinity gradient,suggesting that fluvial input was the primary source of CDOMin the estuary.In high salinity regions,the ratio of peak Cto TOTdecreased while the ratios of two protein-like fluorophores(T1 and T2) to TOTincreased,indicating an obvious contribution of biological activity within this area.IFIof all fluorescent peaks,especially the protein-like fluorescence peaks(T1、T2、B) in the middle layer(18 m) of Sstation were higher than those from the surface layer(0.5 m) and bottom layer(35 m),suggesting that the vertical distribution of CDOMin this station were controlled by both CDOMphotochemistry and biological activity.Peak Cwas weak in the EEMs of the sediment pore water collected in Sstation while peaks T1、T2 and Bwere all very strong,reflecting the significant degradation of protein materials by microbial activity in surface sediment.

• Key words：Chromophoric Dissolved Organic Matter(CDOM)  EEMs  fluorophore  integrated fluorescence  Jiulong River Estuary

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