作　　者： ; ; ; ; ; ;

机构地区： 华东师范大学资源与环境科学学院地理信息科学教育部重点实验室

出　　处： 《地理学报》 2004年第6期918-926,共9页

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(0~2cm)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。 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.

关 键 词： 氮同位素 潮滩 有机质 稳定同位素 示踪 改造作用 枯水 月份 消长变化 季节

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]