中文摘要：

对长江口邻近陆架区表层沉积物的有机物进行碳、氮元素、碳稳定同位素和木质素测定，以分析其物质来源，特别是陆源有机物的迁移埋藏。结果表明，碳与氮含量的比值为6.2-7.7，δ^13C为-19.9×10^-3--22.4×10^-3。8种木质素酚单位的总含量（相对于总有机碳）为0.15×10^-2-1.56×10^-2mg/mg，显著低于长江口门处的2.50×10^-2mg/mg。香草基酚类的酸醛比平均值为0.90，表明该海区的陆源有机物是高度降解的；紫丁香级酚类与香草基酚类的含量之比为（0.78±0.35），肉桂基酚类与香草基酚类的含量之比为（0.13±0.08），表明这些陆源有机物源于草本和木本混合的被子植物。31.5°N以南站位木质素的降解程度比北部的高，草本植物源的贡献更大，被子植物的主导优势也更明显；长江输入的有机物以沿岸堆积为主，具有显著的离岸降低趋势。在31.5°N以北的陆架区，虽然近岸站位陆源有机物的贡献显著高于其他站位，但其他站位并没有离岸递减趋势。这种南北分布差别可能是由海流条件和水深梯度的差异引起的。计算结果显示，该海区表层沉积物中的陆源有机物占总有机物的5%-57%，且主要来自土壤有机质。

英文摘要：

Elemental, stable carbon isotopic and lignin analyses were carried out to study the sources of surface sedimentary organic matter in the adjacent area of the Changjiang Estuary. Ratios of carbon is nitrcyen content vary from 6.2 to 7.7, corresponding with bulk δ^13C values of -19.9 × 10^-3--22. 4 × 10^-3. The content sum of vanillyl, syringyl and cinnamyl phenols produced from the oxidation of 100 mg organic carbon is between 0. 15 × 10^-2 and 1.56 × 10^-2 mg/mg in shelf sediments, comparing with a value of 2.50× 10^-2mg/mg in the mouth of the Changjiang Estuary. Averaged at 0.90, high values of （Ad/Al）v suggest that the terrigenous organic matter in the shelf is highly degraded. S/V （0.78 ± 0. 35） and C/V （0.13±0.08） ratios further indicate that these terrigenous organic matter originate from a mixture of woody and nonwoody angiosperm plants. Lignins in the southern shelf have a higher degree of degradation and more contribution from nonwoody angiosperm sources, which deposits along the coastline with a significant offshore decreasing trend. The distribution of lignin in the north is more homogenous due to the different hydrodynamic conditions. End member calculations suggest that terrigenous organic matter can represent approximately 5% to 57% of total organic matter in various samples with a distinct offshore decreasing trend. Soil-derived terrestrial organic matter may account to majority composition in most samples.