| 摘要: |
| 河流输入的陆源有机碳在河口和陆架区的生物地球化学过程是全球碳循环的重要环节, 对陆源有机质的输入量的估算是研究陆架区的生物地球化学过程的基础。黄河输沙量极大, 为探究其携带的陆源有机质对陆架边缘海有机碳库的影响, 以黄河河口及邻近渤海海域为研究对象, 分析了表层沉积物中的木质素, 结合总有机碳含量、总氮含量和有机碳稳定同位素评估了表层沉积物中有机碳的组成、来源和分布。8种木质素酚单体中, 紫丁香基酚类(S)与香草基酚类(V)的含量比值S/V(0.63±0.31)和肉桂基酚类(C)与香草基酚类含量比值C/V(0.25±0.15), 反映出研究区陆源有机碳主要来自草本被子植物。V系列中木质素酸(Ad)与木质素醛(Al)的比值(Ad/Al)V较高(0.53±0.14), 表明陆源有机质的降解程度较高。利用稳定碳同位素比值δ13C和木质素含量Λ8相结合的土壤有机质-陆生维管植物-水生有机质三端元模型对陆源有机物的贡献的分析结果显示, 土壤有机质、陆源维管植物和水生有机质的平均贡献分别为59.9%±15.0%、7.3%±7.0%、32.8%±11.8%。土壤在陆源有机质中的贡献占有绝对优势, 可能与该区域沉积物的主要源区——黄土高原植被覆盖率低、土壤侵蚀严重有关。 |
| 关键词: 黄河河口 木质素 陆源有机碳 |
| DOI：10.11759/hykx20140214001 |
| 分类号: |
| 基金项目:国家自然科学基金项目(41476062) |
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| Characteristics and environmental implications of lignin in surface sediments from the lower Yellow River-Estuaryadjacent sea |
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WANG Ying-hui,XU Yun-ping
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| Abstract: |
| Buried terrestrial organic carbon on continental shelves plays an important role in the global carbon cycle. To better constrain the characteristics and distributions of terrestrial organic carbon in the Yellow River Estuary and adjacent Bohai Sea, in this study, we analyzed surface-sediment lignin phenols combined with TOC%, TN%, and δ13C. A cross-plot of S/V and C/V indicates that lignin is mainly derived from non-woody angiosperm tissues. The (Ad/Al)V values are between 0.31 and 1.01, with an average of 0.53, indicating a high degree of lignin degradation. A three-end-member (vascular plant, soil organic matter, and aquatic organisms) mixing model based on δ13C and Λ8 reveals that the relative amount of aquatic organisms, soil organic matter, and terrestrial plants is 32.8%, 59.9%, and 7.3%, respectively. The substantially greater contribution of soil organic matter than terrestrial plants is attributed to the severe soil erosion and sparse vegetation cover in the Chinese loess plateau—a major source of the Yellow River sediments. |
| Key words: the Yellow River Estuary lignin terrestrial organic carbon |
