摘要
地下水位作为影响泥炭地形成和发育的关键因素之一,在泥炭地古环境研究中广受关注。本文以采自长白山老里克泥炭地(42°28'49.75"N,128°39'9.02"E;1470 m a.s.l.)100 cm的泥炭岩芯作为研究对象,通过210Pb/137Cs和AMS14C定年方法,建立剖面年代框架,以有壳变形虫为代用指标,定量重建该泥炭地古水位变化。重建结果表明,过去2000年老里克泥炭地整体湿润,经历了比较湿润→非常湿润→比较湿润的变化过程。根据有壳变形虫组合的约束聚类结果,具体可划分为以下3个阶段:1)5~150 A.D.(100~91 cm),泥炭地比较湿润,有壳变形虫主要以喜湿物种茄壳虫(Hyalosphenia sp.)、齿口阿吉尼亚虫(Argynnia dentistoma)、Archerella flavum为主,喜干物种苔藓鳞盖虫(Assulina muscorum)、小匣三角嘴虫(Trigonopyxis arcula)等较少,水位埋深保持在1.2~2.0 cm。2)150~1796 A.D.(91~28 cm),泥炭地非常湿润,地表长期保持1~4 cm积水,但积水深度呈不断变浅趋势。喜湿的茄壳虫(H.sp.)、盘状表壳虫(Arcella discoides type)占优势。3)1796~2017 A.D.(28~0 cm),泥炭地虽较前阶段已显著变干,但仍比较湿润,水位埋深自0.2 cm持续降至5.2 cm。适合中等湿润条件的针棘匣壳虫(Centropyxis aculeata type)、片口匣壳虫(Centropyxis platystoma type)占优势,喜湿的茄壳虫(H.sp.)大幅减少。老里克泥炭地古水位变化受内生过程和气候变化共同影响。
Water table is one of the key factors that controlling the peatland initiation and development,and therefore has attracted a lot of attentions in the field of peatland paleoenvironment reconstruction.In this study,a 100-cm peat core was sampled from the Laolike peatland(42°28'49.75"N,128°39'9.02"E;1470 m a.s.l.)in the Changbai Mountains.The chronological model was established using radioactive nuclides dating methods,namely 210Pb/137Cs and AMS14C dating.Based on testate amoebae data,the peatland water table variations were quantitatively reconstructed using a transfer function.The results show that the water table in the Laolike peatland is relative higher in general but still experienced three different stages,during the past 2000 years.According to the constrained clustering results,the three water table change stages were identified from the testate amoebae assemblages.(1)5~150 A.D.(100~91 cm),the peatland water table was relative high and the testate amoebae were dominated by species that preferring higher water table,such as Hyalosphenia sp.,Argynnia dentistoma,and Archerella flavum,whereas the species that inhabit in relative dry environments,such as Assulina muscorum and Trigonopyxis arcula were less than the other stage.During this stage,the depth to water table(DWT)varied from 1.2 cm to 2.0 cm.(2)150~1796 A.D.(91~28 cm),the water table was much higher than previous stage,with 1~4 cm standing water above the peatland surface for a long time,although the general trend of water table is decreasing.The dominant testate amoebae species were H.sp.,Arcella discoides type.(3)1796~2017 A.D.(28 cm^0),the peatland water table fell significantly compared with the previous stages.The DWT gradually increased from 0.2 cm to 5.2 cm,indicating a decrease in peatland water table.Species that prefer moderately wet conditions,such as Centropyxis aculeata type,Centropyxis platystoma type,were dominant,while the percentange of H.sp.showed a decreasing trend dramatically.Our results suggest that the water table variations of
作者
李艳梅
李鸿凯
董彦民
Li Yanmei;Li Hongkai;Dong Yanmin(Institute of Peat and Mire Research,School of Geographical Sciences,Northeast Normal University,Changchun 130024,Jilin;Key Laboratory of Geographical Process and Ecological Safety of Baishan,Minister of Education,Changchun 130024 Jilin;National Key Laboratory of Environmental Wetland Ecology and Vegetation Restoration,Changchun 130024 Jilin)
出处
《第四纪研究》
CAS
CSCD
北大核心
2020年第5期1170-1179,共10页
Quaternary Sciences
基金
国家重点基础研究发展计划项目(批准号:2016YFC0500407)
国家自然科学基金项目(批准号:41771217)共同资助。
关键词
老里克泥炭地
古水位
有壳变形虫
定量重建
Laolike peatland
depth to water table
testate amoebae
quantitative reconstruction
