2010年秋季长江口口外海域CDOM的三维荧光光谱-平行因子分析

Resolving Characteristic of CDOM by Excitation-Emission Matrix Spectroscopy Combined with Parallel Factor Analysis in the Seawater of Outer Yangtze Estuary in Autumn in 2010

利用三维荧光光谱(EEMs)并结合平行因子分析(PARAFAC)技术,研究了长江口口外海域的有色溶解有机物(CDOM)的荧光组分特征及其河口动力学行为.PARAFAC模型识别出长江口口外海域的CDOM由6个荧光组分组成,即陆源类腐殖质荧光组分C1[330 nm/390(430)nm]、C2(390 nm/480 nm)、C3(360 nm/440 nm)、海洋生物产物组分C5(300 nm/400 nm)及类蛋白质荧光组分C4(290 nm/350 nm)和C6(275 nm/300 nm).结果表明,C1、C2和C3组分在河口混合过程中呈保守行为,特别是在长江口口外高盐度区;C1和C3组分在总组分中所占比例在整个研究区域随盐度增加呈稀释降低趋势,C2组分在总组分中所占比例在整个区域保持不变;C4组分在低盐度区呈保守行为,在高盐度区呈不保守行为,其在总组分中所占比例在整个研究区域呈上升趋势;C5和C6组分则在整个河口混合过程中呈非保守行为,并且它们在总组分中所占比例在高盐度区呈上升趋势.另外,近岸区和远岸区的CDOM吸收系数a(355)存在显著空间差异,近岸区明显大于远岸区,并且近岸区的a(355)和光谱斜率S的范围小于远岸区;CDOM吸收系数a(355)与陆源类腐殖质C1、C2和C3以及类蛋白质色氨酸C4存在较好的正相关性,而与海洋生物产物C5和类蛋白质酪氨酸C6不存在显著相关性,表明近岸区主要受河流输入影响,而远岸区由陆源和现场生物产生共同控制.

The distribution and estuarine behavior of fluorescent components of chromophoric dissolved organic matter in the seawater of outer Yangtze Estuary were determined by fluorescence excitation emission matrix spectra combined with parallel factor analysis.Six individual fluorescent components were identified by PARAFAC models,including three terrestrial humic-like components C1[330 nm/390（430） nm],C2（390 nm/480 nm）,C3（360 nm/440 nm）,marine biological production component C5（300 nm/400 nm） and protein-like components C4（290 nm/350 nm） and C6（275 nm/300 nm）.The results indicated that C1,C2,and C3 showed a conservative mixing behavior in the whole estuarine region,especially in high-salinity region.And the fluorescence intensity proportion of C1 and C3 decreased with increase of salinity and fluorescence intensity proportion of C2 kept constant with increase of salinity in the whole estuarine region.While C4 showed conservative mixing behavior in low-salinity region and non-conservative mixing behavior in high-salinity region,and fluorescence intensity proportion of C4 increased with increase of salinity.However,C5 and C6 showed a non-conservative mixing behavior and fluorescence intensity proportion increased with increase of salinity in high-salinity region.Significantly spatial difference was recorded for CDOM absorption coefficient in the coastal region and in the open water areas with the highest value in coastal region and the lowest value in the open water areas.The scope of absorption coefficient and absorption slope was higher in coastal region than that in the open water areas.Significantly positive correlations were found between CDOM absorption coefficient and the fluorescence intensities of C1,C2,C3,and C4,but no significant correlation was found between C5 and C6,suggesting that the river inputs contributed to the coastal areas,while CDOM in the open water areas was affected by terrestrial inputs and phytoplankton degradation.