沉湖130年来湖泊沉积物有机碳、氮稳定同位素变化及其环境指示意义  

Changes of organic C and N stable isotope and their environmental implication during the past 130 years of Chen Lake

作　　者：张雅 刘力 李朋 胡元平 李琳静 苏业旺 邢新丽[2] 冯江 叶婷 ZHANG Ya;LIU Li;LI Peng;HU Yuan-ping;LI Lin-jing;SU Ye-wang;XING Xin-li;FENG Jiang;YE Ting(Hubei Geological Survey,Wuhan 430034,China;School of Environmental Studies,China University of Geosciences,Wuhan 430074;Administration of Chenhu Wetland Nature Reserve,Caidian District,Wuhan City,Wuhan 431608,China)

机构地区：[1]湖北省地质调查院,湖北武汉430034 [2]中国地质大学(武汉)环境学院,湖北武汉430074 [3]武汉市蔡甸区沉湖湿地自然保护区管理局,湖北武汉431608

出　　处：《中国环境科学》2023年第3期1307-1316,共10页China Environmental Science

基　　金：武汉市多要素城市地质调查示范项目(WHDYS-2020-010);湖北省地质局科技项目(KJ2022-12);湖北省地质局民生地质项目(MSDZ202209)。

摘　　要：通过对2020年沉湖湖心采集的73cm长沉积柱(CH-01)中总有机碳(TOC)、总氮(TN)、有机碳同位素(δ^(13)C_(org))和氮同位素(δ^(15)N)指标的分析,并结合年代测定(^(210)Pb、^(137)Cs比活度测试)结果,分析了130多年来沉湖沉积物有机质的来源,探讨受人类活动影响下湖泊的生态环境变化过程.结果表明:沉湖沉积物平均沉积速率为0.52cm/a,呈缓慢增大趋势.TOC、TN含量变化范围分别为0.89%~3.65%和0.04%~0.20%,δ^(13)C、δ^(15)N值变化范围分别为-29.34‰~-26.13‰和1.67‰~5.48‰,TOC、TN在38~26cm的快速上升对应于1970~1990年沉湖周边人口增长和湖泊改造工程频繁期.沉积物中有机质为混合来源,主要为土壤有机质、陆生C3植物和水生维管束植物.其中土壤有机质和陆生C3植物的贡献较大,1980年后由于人类活动导致湖泊水动力减弱,湿地内水生维管束植物对沉积物有机质的贡献率增大.因此,未来研究要从控制水土流失、合理调控湖泊水文条件等多方面着手,重视人类活动对湖泊生态环境影响.Based on the analysis of total organic carbon(TOC), total nitrogen(TN), organic carbon isotope(δ^(13)C_(org)) nitrogen isotope(δ^(15)N), and the results of dating(^(210)Pb,^(137)Cs) from sediment core collected in the center of the Chen Lake in 2020, the source of organic matter in sediments was identified and the evolution process of lake ecosystem during the past 130 years under the influence of human activity was analyzed.These results showed that the average sedimentary rate was 0.52cm/a, showing a slowly increasing tendency.The contents of TOC and TN ranged from 0.89% to 3.65% and 0.04% to 0.20%, respectively.The values of δ^(13)C and δ^(15)N ranged from-29.34‰ to-26.13‰ and 1.67% to 5.48‰, respectively.The rapid increase of TOC and TN in the depth of 38~26cm corresponded to the period of population growth and lake reconstruction projects around the Chen Lake during 1970~1990.The organic matter in sediments was a mixed source, including soil organic matter, terrestrial C3 plants and aquatic vascular plants.Soil organic matter and terrestrial C3 plants dominant the sedimentary organic compositions.After the 1980, due to the weakening of lake hydrodynamic caused by human activities, the contribution rate of aquatic vascular plants to sediment organic matter in wetland increased.Hence, in the future, more attention should be paid to the impacts of human activities on the lake ecological environment for controlling soil erosion and reasonably regulating the hydrological conditions of lakes.

关 键 词：沉湖 碳氮同位素 有机质 生态环境演化 人类活动 

分 类 号：X141[环境科学与工程—环境科学]