长江口盐度梯度下有色溶解有机物的分布、来源与季节变化

发布时间：2018-07-03 07:23

本文选题：长江口 + 最大浑浊带　；参考：《海洋学报》2017年06期

【摘要】：通过测定有色溶解有机物(CDOM)的吸收光谱和荧光光谱研究了2015年3月和7月长江口盐度梯度下CDOM的分布、组成、来源及河口混合行为等。利用激发发射矩阵荧光光谱(EEMs)并结合平行因子分析(PARAFAC),研究了CDOM的荧光组分特征,共识别出两类4个荧光组分组成,即类腐殖质荧光组分C1(260,375/490nm)、C2(365/440nm)、C3(330/400nm)及类蛋白质荧光组分C4(295/345nm)。结果表明,3月和7月,4种荧光组分的分布模式与总荧光强度都基本一致:从口内到口外,先升高后降低,且4种组分都在河口呈现不保守混合行为,在最大浑浊带处存在添加过程,达到峰值,在口外有去除过程。3月腐殖化指数HIX范围在1.12~7.19,而7月HIX的范围在0.87~6.71;生物指数BIX在3月范围在0.76~1.11,7月为0.62~1.15,表明3月CDOM的腐殖化程度较7月高,而自生贡献比例较7月略低。3月吸收系数α(355)的平均值为0.55m~(-1),7月的略高,为0.61m~(-1),表明7月长江口CDOM的含量略高。光谱斜率比值SR的季节性变化不大,都是近岸低,远岸高,表明CDOM的平均分子质量从口内到口外在逐渐增加。
[Abstract]:The distribution, composition, source and estuarine mixing behavior of CDOM in the Changjiang Estuary in March and July 2015 were studied by measuring the absorption and fluorescence spectra of CDOM. Excitation emission matrix fluorescence spectroscopy (EEMs) and parallel factor analysis (PARAFAC) were used to study the fluorescence composition of CDOM. Two kinds of fluorescence components were identified: C _ 1 (260375/490nm) C _ 2 (365/440nm) C _ 3 (330/400nm) and C _ 4 (295/345nm). The results showed that the distribution patterns of the four fluorescent components in March and July were basically the same as the total fluorescence intensity: from inside and out of mouth, the four fluorescent components increased first and then decreased, and all of them showed an unconserved mixing behavior in the estuary. At the maximum turbidity zone, there exists a process of addition, which reaches the peak value. The humification index in March was 1.127.19, while that in July was 0.870.71, and the biological index BIX was 0.761.11 in March and 0.62 卤1.15 in July, which indicated that the humification degree of CDOM in March was higher than that in July. The average absorption coefficient 伪 (355) was 0.55m-1 in March and a little higher (0.61m-1) in July, indicating that CDOM content in the Changjiang Estuary was slightly higher in July. The seasonal variation of the spectral slope ratio SR is not obvious, which is low near shore and high in far shore, indicating that the average molecular weight of CDOM increases gradually from inside mouth to outside mouth.
【作者单位】：中国海洋大学海洋化学理论与工程技术教育部重点实验室;中国海洋大学化学化工学院;
【基金】：国家重点研发计划项目(2016YFA0600902) 国家自然科学基金项目(41676063,41620104001,41521064)
【分类号】：P734

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