地理学报 ›› 2004, Vol. 59 ›› Issue (6): 918-926.doi: 10.11821/xb200406015

• 生态环境 • 上一篇    下一篇

长江口潮滩有机质来源的C、N稳定同位素示踪

刘敏1, 侯立军2, 许世远1, 欧冬妮1, 蒋海燕1, 余婕1, GardnerWayneS3   

  1. 1. 华东师范大学地理学系, 地理信息科学教育部重点实验室, 上海 200062;
    2. 华东师范大学河口海岸国家重点实验室, 上海 200062;
    3. Marine Science Institute, The University of Texas at Austin, Texas 78373-5015, USA
  • 收稿日期:2004-04-15 修回日期:2004-09-26 出版日期:2004-11-25 发布日期:2010-09-09
  • 作者简介:刘敏 (1964-), 男, 内蒙土左人, 博士, 教授, 博士生导师, 从事区域环境质量演变与环境生物地球化学研究工作。E-mail: mliu@geo.ecnu.edu.cn
  • 基金资助:

    国家自然科学基金资助项目(40131020; 49801018);教育部高等学校骨干教师计划资助项目;上海市重点学科建设项目

Carbon and Nitrogen Stable Isotopes as Tracers to Source Organic Matter in the Yangtze Estuary

LIU Min1, HOU Lijun2, XU Shiyuan1, OU Dongni1, JIANG Haiyan1, YU Jie1, GARDNER Wayne S3   

  1. 1. Department of Geography, Key Laboratory of Geo-information Science of the Ministry of Education, East China Normal University, Shanghai 200062, China;
    2. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;
    3. Marine Science Institute, The University of Texas at Austin, Texas 78373-5015, USA
  • Received:2004-04-15 Revised:2004-09-26 Online:2004-11-25 Published:2010-09-09
  • Supported by:

    National Natural Science Foundation of China, No.40131020, No.49801018; Foundation for University Key Teacher by the Ministry of Education; Shanghai Key Disciplinary Project

摘要:

依据长江河口潮滩自然环境特征和受人文活动影响的差异性,沿长江河口南岸潮滩选取了12个典型的监测站位,并分别于洪水季节 (7月份) 和枯水季节 (2月份) 在各监测站位进行了表层 (0~2 cm) 沉积物样品的采集。对表层沉积物有机质中稳定碳、氮同位素进行分析与测试发现,7月份稳定碳同位素值普遍低于2月份的稳定碳同位素值,其变化范围分别为 -29.8‰ ~ -23.7‰和-27.3‰ ~ -25.6‰;7月份和2月份稳定氮同位素分别为1.0‰ ~ 5.5‰和1.7‰~ 7.8‰。研究区域内,稳定碳、氮同位素的地区分布和季节变化特征揭示,有机质中的稳定碳、氮同位素组成不仅受陆源和海源有机质输入量之间消长变化的影响,同时一系列的生物地球化学过程、人为有机质的输入和沉积物粒度与叶绿素对碳、氮同位素组成均存在不同程度的改造作用。此外,利用稳定碳同位素质量平衡混合模型,还对陆源有机质输入量的贡献率进行了初步定量估算。

关键词: 碳同位素, 氮同位素, 沉积物, 潮滩, 长江, 河口

Abstract:

In this article, we mainly focus on the geochemical characteristics of stable carbon and nitrogen isotopes in order to trace the source and fate of organic matter in the Yangtze estuary and its tidal flat sediments. According to the features of physical geographical environment and the discrepancy in the effects of human activities in the study area, 12 typical sampling stations were selected along the Yangtze estuarine and coastal line. Based on the analysis of stable carbon and nitrogen isotopes in the tidal flat superfacial sediments from the Yangtze estuary, it was found that the ratios of stable carbon and nitrogen isotopes were respectively -29.80‰~-23.7‰ and 1.0‰~5.5‰ in the flood seasons, while they were -27.3‰~-25.6‰ and 1.6‰~7.7‰ in the dry seasons respectively, indicating that the seasonal distribution of discharges from the Yangtze River has significantly affected the seasonal variation of stable carbon and nitrogen isotopes in sedimentary organic matter. In general, the distribution of stable carbon and nitrogen isotopes revealed the mixing inputs of terrigenous and marine organic matter controlled the stable carbon and nitrogen isotope compositions in sedimentary organic matter. However, a series of physical, chemical and biogeochemical processes occurring in the local environments, to some extent, have the significant influence on the stable carbon and nitrogen isotope compositions in organic matter.

Key words: stable carbon isotope, stable nitrogen isotope, sediment, the Yangtze estuary