| 长江口盐沼土壤有机质分布与矿化的空间差异 |
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| 引用本文： | 陈庆强,杨艳,周菊珍,张国森,崔莹.长江口盐沼土壤有机质分布与矿化的空间差异[J].沉积学报,2012,30(1):128-136. |
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| 作者姓名： | 陈庆强 杨艳 周菊珍 张国森 崔莹 |
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| 作者单位： | 华东师范大学河口海岸学国家重点实验室,上海,200062 |
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| 摘 要： | 在长江口崇明东滩两类植被(互花米草、土著植被)区域分别选择一条纵向剖面,在高潮滩、中潮滩及光滩取得柱状样,利用颗粒有机碳(POC)含量、碳稳定同位素组成、土壤C/N比与颗粒组成等资料,研究盐沼有机质的分布与矿化特征。结果表明,两个纵向剖面的相同高程部位柱样之间,颗粒有机碳δ13C与POC含量的深度特征均存在显著差异;两个柱样的δ13C与POC含量的平均值均相差较大。互花米草对高潮滩柱样有机质的含量与组成均产生了明显影响,对中潮滩柱样有机质组成已有一定影响;土著植被对高潮滩柱样有机质组成的影响显著。盐沼植被对土壤有机质的分布与矿化均产生了明显影响。高潮滩柱样矿化阶段不同的有机质组分混杂,中潮滩柱样有机质的组成相对简单,矿化程度较弱。柱样粘粒含量与含水量在垂向上变化频繁,盐沼原始沉积层序对柱样的物质分布特征具有本底制约。不同高程部位柱样之间,有机质的深度分布特征以及矿化程度差异显著,盐沼碳动态受到潮滩特征性动力沉积过程的显著影响。
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| 关 键 词： | ,盐沼,,,碳稳定同位素,,碳矿化,,长江口 |
Spatial Differentiation of Soil Organic Matter Distribution and Mineralization in the Salt Marsh of the Yangtze Estuary |
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| CHEN Qing-qiang,YANG Yan,ZHOU Ju-zhen,ZHANG Guo-sen,CUI Ying.Spatial Differentiation of Soil Organic Matter Distribution and Mineralization in the Salt Marsh of the Yangtze Estuary[J].Acta Sedimentologica Sinica,2012,30(1):128-136. |
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| Authors: | CHEN Qing-qiang YANG Yan ZHOU Ju-zhen ZHANG Guo-sen CUI Ying |
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| Institution: | (State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200062) |
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| Abstract: | Two transects(Transect I,Transect II) were selected in areas with Spartina alterniflora,and native vegetation,respectively,for investigation of both distribution and mineralization of soil organic matter(SOM) in the Chongmingdongtan salt marsh of the Yangtze Estuary,China.This study is based the on content of particulate organic carbon(POC),δ13C value of POC,molar ratio of C/N,and grain size characteristics of drilling cores in high tidal flat(core DT-01-2,core DT-08-1),middle tidal flat(core DT-02-1,core DT-08-2) and bare flat(core DT-03-2,core DT-08-3).Cores with the same altitude at the two transects contrast in variations of both POC content and δ13C value with depth,and are different in average values of δ13C and POC content,respectively.The average content of POC of core DT-01-2(0.8%) is markedly greater than that of POC of core DT-08-1(0.47%).The average content of POC of core DT-02-1(0.38%) is greater than that of POC of core DT-08-2(0.11%).δ13C values of core DT-08-1 average-24.52‰,and the average value of δ13C of core DT-01-2 is-19.73‰.The average value of δ13C of core DT-08-2(-22.06‰) is close to that of δ13C of core DT-02-1(-22.92‰).Therefore,the variation trend of SOM composition from high tidal flat(core DT-01-2) to middle tidal flat(core DT-02-1) of Transect I is not consistent with that of SOM composition from high tidal flat to middle tidal flat of Transect II.This may be due to differences in SOM composition between the two transects. Transect I was located in the area with invasive Spartina alterniflora that is of C4 type plant.POC content is positively correlated with δ13C value for core DT-01-2,suggesting that organic components from Spartina alterniflora are predominant in SOM at the drilling site.Core DT-01-2 contrasts markedly with core DT-08-1 in correlation between δ13C value and POC content.This is due to the difference in vegetation type between the sites of the two cores,with C3 type plant at the site of core DT-08-1 and C4 type plant at the site of core DT-01-2.The average content of POC of core DT-01-2 is the greatest among those of POC of the studied cores,which may correlate to the high primary production of Spartina alterniflora.Core DT-02-1 is different with core DT-01-2 in correlation between δ13C value and POC content,and is similar to core DT-08-1 that is located in the area with native vegetation.This suggests that SOM at the site of core DT-02-1 are mainly composed of organic components from primary sediments that are transported by the Yangtze River.The correlation between δ13C value and POC content of core DT-02-1 has not been changed thoroughly by the organic components from Spartina alterniflora,which may correlate to the weaker mineralization of SOM,due to the limited time period for the development of middle tidal flat.Spartina alterniflora has produced marked impacts on both content and composition of SOM in the high tidal flat,and discernable impacts on composition of SOM in the middle tidal flat.Native vegetation has exerted marked influence on composition of SOM in the high tidal flat.Salt marsh vegetations have therefore made remarkable impacts on distribution and mineralization of SOM.Organic components of different stages of mineralization are mixed in the SOM of the high tidal flat.SOM composition is relatively simple in the middle tidal flat,indicating that SOM mineralization is less complicated there.Both clay content and water content vary markedly with depth,suggesting that sedimentary sequences have initial constraints on distribution of materials with depth in the salt marsh.Cores with different altitudes contrast markedly in both vertical distribution and mineralization of SOM.Soil carbon dynamics are constrained by the characteristic sedimentary processes on the salt marsh of the Yangtze Estuary. |
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| Keywords: | salt marsh stable carbon isotope carbon mineralization the Yangtze Estuary |
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