应用木质素示踪楚科奇海表层沉积物中有机碳的来源和降解程度

埋藏在海洋沉积物中的有机碳是大气二氧化碳的净汇，而埋藏过程主要发生在陆架区。北冰洋拥有全球最大的陆架，接收大量来自河流和沿岸侵蚀输运的陆源有机碳，楚科奇海作为北冰洋的边缘海，是有机碳埋藏的重要海区之一。本研究选用楚科奇海和海台的表层沉积物（陆架区33~82.69 m，陆坡区164.63~3 763 m），通过木质素，结合粒度、比表面积、有机碳百分含量（OC%）、有机碳稳定同位素（δ13C）等指标来示踪楚科奇海沉积物有机碳的来源和降解程度。结果表明，有机碳载荷从陆架到陆坡有明显的降低趋势；δ13C的范围指示有机碳可能来自苔藓、草本裸子植被、浮游植物和冰藻等；木质素丁香基酚（S）与香草基酚（V）的比值（S/V）和肉桂基酚（C）与香草基酚（V）的比值（C/V）表明裸子植物的草本组织贡献了更多的陆源有机碳；此外，较高含量的C9DA二酸（干酪根氧化产物）表明干酪根也可能是楚科奇海表层沉积物中有机质来源的重要组成。指示降解的参数（Ad/Al） s、（Ad/Al） v、（Ad/Al） p、3，5-Bd/V]在陆架和陆坡沉积物中的差异表明陆坡沉积物中有机质的降解过程受到水动力分选以及原位降解等因素的影响更为明显。

Sources and degradation of organic carbon in the surface sediments across the Chukchi Sea, insights from lignin phenols

Organic carbon (OC) buried in the marine sediments performs as the net sink of atmosphere CO₂. The Arctic Ocean has the largest shelf and receives a mass of terrestrial OC transported by the rivers and coastal weathering. The Chukchi Sea is one of the marginal seas of the Arctic Ocean where terrestrial OC was buried. In this study, surface sediments from the Chukchi Sea and plateau are selected and divided into two groups:the shelf (33-82.69 m) and the slope (164.63-3 763 m). Lignin phenols, in combined with stable carbon isotope (δ13C), OC%, grain size and specific surface area (SSA) are used to trace the sources and degradation of terrestrial organic carbon in this region. The results show that OC loading decrees dramatically from the shelf to the slope. The wide range of δ13C shows a multi-sourced contribution of plants like shrubs, grasses, and conifers. Gymnosperm tissue is relatively more dominant than angiosperm tissue, whereas non-woody tissue is more dominant than woody tissue upon the surface sediments of the Chukchi Sea, according to the C/V and S/V ratios. In addition, the C9DA, which is obtained from the aliphatic-rich kerogen, is relatively high among Das. This implies that kerogen can play a pregnant role in the sources of the OC in the Chukchi Sea and Plateau.