杭州湾外泥质区柱状沉积物中木质素的分布特征及其环境指示意义

本文对杭州湾外泥质区3根沉积柱样中木质素的分布特征及有机物来源进行了研究，旨在揭示短时间尺度内该区域沉积环境的变化如何受到人类活动的影响。结果表明:海源有机物是该海域有机物相对主要的来源；柱状沉积物Ra7、Za6和Zb7的木质素含量Λ8（以OC归一化）分别为（1.06±0.29）×10-2、（0.89±0.33）×10-2、（0.99±0.20）×10-2。总体来讲，受长江冲淡水影响区域木质素含量较高，且在短时间尺度内陆源有机物的贡献随着年代增加逐渐减少，而东海环流体系和人类活动是影响柱状样中有机物分布的重要因素；木质素的植被参数S/V和C/V的范围分别为0.33~1.35和0.07~0.26，两者的交叉作图说明Ra7和Za6中木质素的母源植被以被子植物草本组织为主，Zb7则是被子植物草本组织和裸子植物草本组织的混合；降解参数Ad/Al和P/（V+S）分别在0.30~0.60和0.39~0.63之间，揭示沉积柱中的木质素经历了中等程度的氧化和去甲基/去甲氧基降解。

Distribution characteristics of lignin in sediment cores from the mud area off Hangzhou bay and the implication for regional sedimentary environment

In this paper,we studied the distribution characteristics of lignin in three sediment cores Ra7,Za6 and Zb7 from the mud area off Hangzhou bay.The organic sources were discussed to reveal the influence of human activities on the change of regional sedimentary environment in a short time scale.The results showed that the organic matter in the study area was predominantly from marine sources relative to terrestrial.The lignin contents normalized to organic carbon (Λ8) were (1.06±0.29)×10-2,(0.89±0.33)×10-2 and (0.99±0.20)×10-2 in Ra7,Za6 and Zb7,respectively.Overall,the lignin content was the highest at site Ra7 where it is mostly affected by Yangtze River diluted water,and the contribution of terrestrial organic matter was gradually reduced in a short time scale.The circulation system of the East China Sea and anthropogenic activities were the key factors influencing the distribution of organic matter in this area.The lignin vegetation parameters S/V (0.33~1.35) and C/V (0.07~0.26) showed non-woody angiosperm tissues were the main source of lignin in Ra7 and Za6,whilst a mixture of non-woody angiosperm and gymnosperm tissues were indicated for Zb7.The degradation parameters were in the range of 0.30 to 0.60 and 0.39 to 0.63 for Ad/Al and P/(V+S),respectively.These values suggested that a moderate oxidation and a moderate demethylation/demethoxylation had occurred in the cores.