拉萨—帕勒德布尔样带表土中生物标志化合物的气候意义

发布时间：2018-03-08 06:36

本文选题：表层土壤　切入点：正构烷烃　出处：《中国地质大学(北京)》2016年博士论文　论文类型：学位论文

【摘要】：近年来,生物标志化合物类的一些指标(如正构烷烃、四醚膜类脂物等)在古气候变化的研究当中取得了丰硕的成果,但这些生物标志物的指标在不同的地区存在着较大的区域差异。因此,开展相关指标的现代过程研究对进一步地理解指标的气候意义及影响因素具有重要的意义。本文对中国拉萨至尼泊尔帕勒德布尔样带表土样品中的正构烷烃和四醚膜类脂物进行了分析,并与气象记录进行了对比,取得的主要研究成果如下：(1)通过对不同植被类型土壤中的正构烷烃进行分析,发现样带中正构烷烃的分布在热带雨林和阔叶林地区呈现双峰分布模式,最高峰出现在C_(31)和C_(23),该种分布模式可能在热带雨林地区具有普遍性；在暖温带的针阔叶混交林区,长链正构烷烃的分布特征为n-C_(31)n-C_(33)n-C_(27),这种分布模式是森林地带比较典型的特征；在高山灌木和草甸地区,正构烷烃以C_(31)最为丰富,但亦含有较高含量的中链正构烷烃C_(23)。(2)通过对比分析正构烷烃和气象数据发现,样带土壤中正构烷烃的平均碳链长度(ACL)与温度和降雨之间均呈现线性正相关关系,而碳优势指数(CPI)与温度和降雨量之澡呈现线性负相关关系。(3)研究结果显示,正构烷烃的两个参数(ACL_(27-35)、CPI_(27-35))和温度之间的相关系数都不太大。然而,将正构烷烃的这两个指标(ACL_(27-35)/CPI_(27-35))进行一定的数据拟合发现,拟合温度与采样区域观测到的年均温度之间的相关系数得到了提高。(4)样带土壤中四醚膜类脂物的含量以支链型bGDGTs为主,也含有少量的类异戊二烯型GDGTs (iGDGTs)。支链型bGDGTs的各组分与环境因素之间呈现出很好的线性相关。(5)本文的研究结果显示,四醚指数TEX86与年均温度和降雨量之间的线性相关性较弱,相关系数R的值分别为0.50、0.47；环化指标与各环境因子之间均没有表现出明显的线性相关；甲基化指数MBT与年平均气温的线性相关性较高,相关系数R的值为0.80,且甲基化指标也与降水量变化之间存在一定的关联。(6)在本文中,MBT/CB T指标与温度和降雨量之间均呈现出线性高度正相关关系,相关系数R的值分别为0.82、0.78。而在本文的湿润地区,MBT/CBT指标与年均温度线性显著相关,与年均降雨量无关；在干旱地区,MBT/CBT指标与年均温度和降水量均呈现线性弱相关。
[Abstract]:In recent years, some indicators of biomarkers (such as n-alkanes, tetraether membrane lipids, etc.) have achieved fruitful results in the study of paleoclimate change. However, these biomarkers have significant regional differences in different regions. It is of great significance to further understand the climatic significance of the index and its influencing factors. This paper deals with normal alkanes and four alkanes in the topsoil samples of Lhasa to Nepal Paldebur transect, Nepal. Ether membrane lipids were analyzed. And compared with the meteorological records, the main research results obtained are as follows: 1) through the analysis of normal alkanes in soils of different vegetation types, It is found that the distribution of n-alkanes in the transect shows a bimodal distribution pattern in the tropical rain forest and broad-leaved forest area, and the highest peak appears in C ~ (-1) and C _ (23) C _ (23). This distribution pattern may be universal in the tropical rainforest region, and in the coniferous broad-leaved mixed forest region in the warm temperate zone, The distribution characteristics of long chain n-alkanes are n-CSCH31n-CJ ~ (33) n-C / C _ (27), which is a typical feature in forest zone, and is most abundant in Alpine shrubs and Meadow areas (C ~ (31)). But it is also found that the average length of carbon chain (ACLL) of n-alkanes in the soil is positively correlated with temperature and rainfall through the comparative analysis of normal alkanes and meteorological data. The results showed that the correlation coefficient between the two parameters of normal alkane (ACLS) 27-35 and CPI (27-35) and temperature was not very large. The correlation coefficient between the fitting temperature and the average annual temperature observed in the sampling area was increased. The content of tetraether membrane lipids in the soil of the transect was mainly of branched-chain bGDGTs, and the correlation coefficient between the fitting temperature and the average annual temperature observed in the sampling area was increased. There is also a small amount of isoprene type GDGTs iGDGTs.There is a good linear correlation between the components of branched bGDGTs and environmental factors. The results of this paper show that the linear correlation between tetraether index TEX86 and average annual temperature and rainfall is weak. The correlation coefficient R was 0.50 ~ 0.47 respectively. There was no obvious linear correlation between the cyclization index and the environmental factors, and the linear correlation between the methylation index MBT and the annual mean temperature was higher. The correlation coefficient R is 0.80, and there is a certain correlation between methylation index and precipitation change.) in this paper, MBT / CB T index has a linear and high positive correlation with temperature and rainfall. The correlation coefficient R is 0.82 ~ 0.78, respectively. In humid area, MBT / CBT index is linearly correlated with annual temperature, but not with average annual rainfall, while in arid area, MBT / CBT index is linearly weakly correlated with average annual temperature and precipitation.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P532;P593

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