Mixing behavior, biological and photolytic degradation of dissolved organic matter in the East China Sea and the Yellow Sea
Mixing behavior, biological and photolytic degradation of dissolved organic matter in the East China Sea and the Yellow Sea
复制标题
东海和黄海溶解有机物的混合行为、生物和光解降解
DOI：
10.1016/j.scitotenv.2020.143164
复制
发表时间：
2021
影响因子：
9.8
通讯作者：
Gui-Peng Yang
中科院分区：
文献类型：
--
作者：
Lin Yang;Jing Zhang;Gui-Peng Yang
用溶解有机物(DOM)的光学性质作为指示海洋DOM发生的量变和质变的指标。采用吸收光谱和荧光激发-发射矩阵平行因子分析方法，研究了春夏季东中国海和黄海海水中发色DOM和溶解有机碳的时空分布、生物有效性和光反应活性。在4个月的实验室研究中，我们测量了6个常用光学指数的变化，包括光谱斜率(S275-295)、斜率(SR：S275-295/S350-400)、比紫外线吸光度(SUVA254)、类蛋白质组分与类腐殖质组分之和的比率(C蛋白/Chumic)、生物指数(Bix)和腐殖化指数(Hix)，以确定它们在生物和光化学降解过程中的变化。ECS和YS的CDOM光谱特征具有明显的季节变化，表明夏季DOM受陆源和高芳烃含量的影响比春季更大，这可能是长江流量、浮游植物产量和生物活性增加导致DOM产量增加的结果。盐度与光学参数(SUVA254、S275-295、S350-400、C蛋白/Chumic)之间的显著相关性表明，水的混合强烈地影响了这些光学参数的分布。DOM的生物反应性和光反应性随原料的不同而不同，固有的类蛋白质DOM比陆地DOM更容易生物降解。光降解过程优先作用于CDOM，而不是无色DOM。这些结果表明，在混合、生物降解和光降解过程中，DOM的光学参数发生了明显的变化，并解释了DOM在ECS和YS中的季节分布。
Optical properties of dissolved organic matter (DOM) were used as an indicator of the quantitative and qualitative changes occurring in marine DOM. The spatiotemporal distribution, bioavailability, and photoreactivity of chromophoric DOM (CDOM) and dissolved organic carbon (DOC) were investigated in the East China Sea (ECS) and the Yellow Sea (YS) during spring and summer using absorption spectroscopy and fluorescence excitation-emission matrix–parallel factor analysis. Over a 4-month laboratory study, we measured changes in six commonly used optical indices, including spectral slope (S275–295), slope ratio (SR: S275–295/S350–400), specific ultraviolet absorbance (SUVA254), ratio of the sum of protein-like components to the sum of humic-like components (Cprotein/Chumic), biological index (BIX), and humification index (HIX) to determine their changes following biological and photochemical degradation processes. Significant seasonal variations were observed in the spectral characteristics of CDOM in the ECS and the YS, indicating a stronger influence of the terrestrial origin and highly aromatic content of DOM in summer than in spring; this result was likely the consequence of an increase in the Changjiang River discharge, phytoplankton production, and biological activity, resulting in an increase in DOM production. Significant correlation between salinity and optical parameters (SUVA254, S275–295, S350–400, Cprotein/Chumic) indicated that water mixing strongly influenced the distributions of these optical parameters. The bioreactivity and photoreactivity of DOM varied depending on the source material, and the autochthonous protein-like DOM was more prone to biodegradation than the terrestrial DOM. The photodegradation processes acted preferentially on the CDOM than the colorless DOM. These results demonstrated that the optical parameters exhibited distinct changes during the mixing and the biodegradation and photodegradation processes and explained the seasonal distribution of DOM in the ECS and the YS.