黄河口潮间带沉积物中木质素的分布和降解特征

本文以木质素为示踪物，认识陆源有机碳在黄河口潮间带的降解和输送特征。现场调查和样品采集进行于2012年5月、8月和11月，以及2013年3月。结果表明:黄河口潮间带有机碳含量为0.06%~0.40%，δ13C变化范围为-24.4‰~-20.4‰，表现为陆海混合来源特征；木质素Σ8含量范围为0.13~0.54 mg/10g dw，均值为0.23 mg/10g dw，由黄河口门向南北递减；Λ8为0.49~2.42 mg/100 mg OC，均值为1.35 mg/100 mg OC，由南向北逐渐降低；木质素主要来源为被子植物草本和木本组织，草本和木本组织的相对贡献呈现季节变化；木质素通过氧化和去甲基/甲氧基2种过程降解，其中去甲基/去甲氧基降解作用更强，降解水平处于中等偏强。

Distribution and degradation of lignin in the sediment of intertidal mudflat of Yellow River estuary

Organic carbon, carbon stable isotope (δ13C) and lignin were applied to explore the distribution and degradation of terrigenous organic matters in the sediment of intertidal mudflat of Yellow River estuary. The results showed that, the organic carbon content varied between 0.06% and 0.40%, and δ13C ranged from-24.4‰ to-20.4‰, which implied multiple sources of organic carbon in study area.Σ8 varied between 0.13 and 0.54 mg/10g dw with an average of 0.23 mg/10g dw, decreasing from the mouth of Yellow River to northern and southern mudflats.Λ8 varied between 0.49 and 2.42 mg/100 mg OC, with an average of 1.35 mg/100 mg OC, decreasing from southern to northern mudflats. LPVI showed that, lignins were primarily derived from herbaceous and woody tissues of angiosperms and the contribution of herbaceous and woody tissues altered seasonally in study area. Lignin degraded through oxidation and demethylation/demethoxylation, in which demethylation/demethoxylation contributed more.