西太平洋冬季上层水体有色溶解有机物的分布和转化特征

为深入解析西太平洋溶解有机碳的生物地球化学过程，本研究于2015年12月至2016年1月，开展了西太平洋上层水体有色溶解有机物（CDOM）吸收光谱和荧光光谱特征研究。研究结果表明，西太平洋上层水体CDOM吸收系数a（320）变化范围为0.01~1.07 m-1，平均值为0.18 m-1；其较高值位于100~200 m水层，表层的海水相对含量较低，主要以有机物的光化学分解为主。采用PARAFAC分析CDOM三维荧光光谱特征，得到1种类腐殖质组分C2（252（310 nm）/405 nm）及2种类蛋白组分C1（224（276 nm）/335 nm）和C3（224（260 nm）/300 nm），其中类腐殖质荧光组分占总荧光强度的11%~22%，蛋白质荧光组分占总荧光强度的78%~89%，蛋白质荧光中类色氨酸和类络氨酸组分对荧光强度的贡献相当。洋流在大尺度上控制西太平洋CDOM的分布特征，两流交界处和环流形成区域的CDOM相对含量较高，荧光信号较强。西太上层水体CDOM相对含量和荧光信息，与温度、盐度、DO和营养盐等理化因素之间的相关分析结果表明，CDOM主要成分类蛋白质的产生主要受上层水体初级生产过程控制。

Distribution and transformation of CDOM in the upper waters of western Pacific Ocean in winter

In order to issue the biogeochemistry of dissolved organic carbon (DOC) in the western Pacific Ocean, the absorbance and fluorescence spectrums of chromophoric dissolved organic matter (CDOM) were studied in the upper waters from November 2015 to January 2016. Results showed that, the absorbance coefficient a(320) of CDOM ranged at 0.01-1.07 m^-1 with an average of 0.18 m^-1. The higher a(320) were located in the 100-200 m water layers, while the lower values were in the surface water layers, which may due to the photochemical decomposition process. Parallel factor analysis was applied to analyze the three-dimensional fluorescence spectrum of CDOM, including one humic-like component of C2 (252(310) nm/405 nm) and two protein-like components of C1 (224(276 nm)/335 nm) and C3(224(260)nm/300 nm). The humic-like components accounted for 11%-22% in fluorescence intensity, while protein-like components dominated in 78%-89%. Protein-like components, which were composed of tryptophan-like and tyrosine-like compounds, contributed substantially to the fluorescence intensity. The higher CDOM fluorescence was observed in the boundaries between ocean currents and circulation formative regions. And oceanic currents controlled the general CDOM distribution in large scale in study area. In addition, positive relationships were discovered among the relative contents of CDOM, CDOM fluorescence, temperature, salinity, DO and nutrients in the upper water layers of the western Pacific Ocean. It was suggested that the CDOM production were more closely related with primary production in upper water layers.