渤海表层沉积物中氨基糖的分布特征及对有机质来源和降解的指示探究

本文对渤海表层沉积物中氨基糖（ASs）的含量和组成进行了调查，并结合总有机碳（TOC）、总氮（TN）、稳定碳同位素（δ13C）和粒度等参数对渤海沉积有机物（SOM）的来源和细菌源有机质的贡献进行了探讨。渤海表层沉积物中ASs的含量为0.22～1.89 μmol/g，平均值为（1.01 ± 0.52）μmol/g。双端元模型结果表明，渤海表层沉积物中陆源有机质的贡献（f_t）为28.1%～42.8%，并且f_t值随着距黄河口距离的增加而逐渐减小。有机碳含量较低的黄河泥沙的沉积可能是导致黄河口和渤海海峡附近海域表层沉积物中TOC、TN和ASs含量较低的原因。而在受黄河影响较小的渤海其他海域中，TOC、TN和ASs的含量较高，这可能与黏土矿物和海洋初级生产力对SOM的影响有关。ASs对TOC和TN的贡献（AS-C%和AS-N%）分别为（1.5 ± 0.7）%和（1.9 ± 0.9）%。氨基葡萄糖/氨基半乳糖（GlcN/GalN）的值低于3，表明细菌源有机质可能是渤海表层沉积物中ASs的主要来源。渤海表层沉积物中细菌源有机质对TOC和TN的贡献（Bacteria-C%和Bacteria-N%）分别为（10.7 ± 8.3）%和（12.6 ± 9.6）%。

Study on the distributions of amino sugars and their indications to organic matter sources and degradations in the surface sediments of the Bohai Sea

The contents and compositions of amino sugars (ASs) were investigated in the surface sediments of the Bohai Sea. Combined with analysis of total organic carbon (TOC), total nitrogen (TN), stable carbon isotope (δ13C) and grain size, the sources of sedimentary organic matters (SOM) and bacterial contributions were studied. The concentrations of ASs ranged from 0.22 to 1.89 μmol/g, with an average value of (1.01 ± 0.52) μmol/g in the surface sediments of the Bohai Sea. According to the two end-members mixing model, the fractions of terrigenous organic matter (f_t) ranged from 28.1% to 42.8% in the surface sediments, which gradually decreased from the Yellow River Estuary to the sea. The deposition of “low organic carbon” sediments of the Yellow River may be responsible for low TOC, TN and ASs contents in the surface sediments of the Yellow River mouth and the Bohai Strait. However, the relatively high contents of TOC, TN and ASs may be related to the effects of clay minerals and primary production on SOM in the sites where less affected by the Yellow River. The average contributions of ASs to TOC and TN (AS-C% and AS-N%) were (1.5 ± 0.7)% and (1.9 ± 0.9)%, respectively. The ratios of glucosamine to galactosamine (GlcN/GalN) below 3, indicating that bacterial organic matter may be the main source of ASs in the surface sediments of the Bohai Sea. The mean contributions of bacterial organic matter to TOC and TN (Bacteria-C% and Bacteria-N%) in the surface sediments of the Bohai Sea were (10.7 ± 8.3)% and (12.6 ± 9.6)%, respectively.