渤海有色溶解有机物的三维荧光光谱特征

THE FLUORESCENCE EXCITATION EMISSION MATRIX SPECTROSCOPY OF CHROMOPHORIC DISSOLVED ORGANIC MATTER IN THE BOHAI SEA

本文采用三维荧光光谱(FEEMs)技术,结合FEEMs特定光谱区荧光区域积分(FRI)法,测定了2010年9月中旬渤海23个站位不同层次的有色溶解有机物(CDOM)样品,以探讨渤海CDOM组分的水平和垂直分布特征以及控制因素。FEEMs的总累计积分和各荧光团的荧光区域积分比例可作为表征海域CDOM分布特征的一个良好指标,且优于常规的单点荧光法。结果表明,渤海CDOM中含有类腐殖质荧光团A、B、C,类色氨酸荧光团M,以及类酪氨酸荧光团N。从沿海至外海,CDOM总累计积分值不断减小。其中紫外区类腐殖质A的荧光区域积分比例无显著变化;可见区陆源类腐殖质B的荧光区域积分比例也不断减小,表明陆源输入为沿海区域CDOM的主要来源;而可见区海源类腐殖质C、类蛋白质荧光团M、N的荧光区域积分比例和叶绿素浓度不断升高,显示了生物活动的贡献。从层次来看,沿海CDOM的总累计积分为:表层>底层>中层;而外海CDOM的总累计积分呈相反趋势。其中,紫外区类腐殖质A的荧光区域积分比例在整个海域最小,垂直分布无明显变化;可见区陆源类腐殖质B的荧光区域积分比例与沿海CDOM总累计积分相一致;可见区海源类腐殖质C、类蛋白质M和N的荧光区域积分比例与外海CDOM总累计积分相一致,这反映了CDOM的垂直分布是由光化学反应、生物作用和沉积物再悬浮共同控制的特性。

Abstract Fluorescence Excitation Emission Matrix Spectra （FEEMs） is often used to characterize the composition and properties of Chromophoric Dissolve Organic Mater （CDOM） in water. We adopted Fluorescence Regional Integration （FRI） to study 23 samples of different layers of the Bohai Sea, collected in September 2010, to characterize the horizontal and vertical distributions of CDOM in the Bohai Sea and the impact factors. The result indicate that the CDOM contained hurnics-like （A, B, C）, tryptophan-like （M）, and tyrosine-like （N） matters. The total cumulative integral value （ФT） of CDOM and FRI of each fluorophore （Фi） are good indices to characterize the distributions, and are better than traditional point fluorescence method in performance. The ФT of CDOM decreased gradually from coastal to coast. The FRI of ultraviolet region humics-like （A） had no obvious change. FRI of visible region terrigenous humics-like （B） decreased gradually, suggesting that terrigenous inputs was the primary source of CDOM in the coastal; FRIs of visible region autochthonous humics-like （C）, protein-like fluorophores （M and N） and chl a concentration increased, indicating obvious contribution of biological activity within the area. The ФT and FRI of terrigenous humics-like （B） are greater in the surface layer than those in the middle layer and bottom layer, and the ФT and FRI of the autochthonous humics-like （C） and protein-like fluorophores （M and N） are greater in the middle layer than those in the surface and bottom ones, suggesting that the vertical distribution of CDOM in the areas were controlled by CDOM photochemistry, sediment resuspension, and biological activity.