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赛里木湖流域表土及沉积物中有机质环境信息研究
陈京
学位类型硕士
导师吉力力·阿不都外力
2016
学位授予单位中国科学院大学
学位授予地点北京
学位专业自然地理学
关键词赛里木湖 气候变化 有机质 影响因素 环境演变
摘要赛里木湖是新疆干旱区的高山冷水湖,生态环境脆弱且敏感性高。它位于中国天山西部,是认识天山西段地区环境演变的窗口。赛里木湖的地理位置,赋予其在气候及环境研究中的重要作用。由于赛里木湖流域实测资料有限,更长时间序列的环境信息没有记录,但湖泊沉积物汇集了丰富的流域环境变化的信息,是陆地环境变化的天然档案库,是研究过去环境变化的良好载体。所以,通过综合赛里木湖流域实测数据和湖泊沉积记录数据研究,可以揭示赛里木湖流域气候环境变化和近二百年来区域环境的演变特征。该研究不仅揭示赛里木湖及流域环境演变的规律及机理,为保护赛里木湖流域区域生态环境、保障流域生态安全提供决策参考;而且有利于丰富和完善天山山地湖泊生态环境数据库,为干旱区山地湖泊及流域的环境治理与规划提供借鉴。通过研究得到了以下结果: 1. 基于实测气象数据,采用了趋势分析、Mann-Kendall突变检验、小波分析等方法,研究了近50年赛里木湖流域气温、降水的变化趋势。赛里木湖流域近54a年平均气温在波动中呈明显上升趋势,1996年为年平均气温升高的突变年份,年平均气温在6a,13a,28a上存在周期振荡。年降水量波动较大,但是总体上呈上升趋势,1986 年是年降水量增多突变点,赛里木湖流域年降水量在28 a、21a、12a和5a左右周期波动明显。 2. 对赛里木湖流域的遥感图像,在经过预处理后,用最大似然监督分类方法进行监督分类,发现1990-2015赛里木湖流域草地、林地和冰川积雪面积减少,裸地面积增加。 3. 对赛里木湖表土样品中有机碳和全氮进行了相关性分析,研究发现两者相关性较高。依据不同植被类型表土碳氮含量,发现低植被覆盖度的草地表土中有机碳和全氮含量明显低于高植被覆盖度的草地和针叶林,并且探讨了赛里木湖流域表土碳氮含量的影响因素。 4. 在分析赛里木湖湖泊沉积物中有机氮含量(TN)、有机碳含量(TOC)及其碳同位素(δ13Corg)以及色素等指标的变化特征的基础上,结合沉积物中有机指标的环境意义的探讨,揭示了新疆赛里木湖湖泊沉积物中有机质所蕴含的环境信息。赛里木湖沉积物中总有机碳含量、总氮含量的变化反映了流域初级生产力的变化;有机碳同位素(δ13Corg)反应了湖泊内外源的混合信息;沉积物色素CD和TC变化是指示湖泊初始生产力和有机质保存条件变化的指标,间接指示了湖泊-流域水热配置环境。结合有序样品聚类分析方法,可以将赛里木湖近代环境划分为四个阶段。
其他摘要Sayram Lake is a mountain lake in the arid area of Xinjiang, its ecological environment is fragile and high sensitivity. Because it is located in the Western Tianshan Mountains of China,we can correctly understand the evolution of the Western Tianshan area environment change by the sediment of this lake. The special geographical position of Sayram Lake gives its important role in the climatic and environmental research. Due to the limited measured data, longer time series of environmental information is not recorded. Lake sediment collects environmental change information of watershed. It is a natural archive of land environment changes and a good carrier to study the environmental changes in the past. So, we reveal the environmental responses of natural and human activities by measured data and lake sediment record in recent two hundred years. The study not only reveals the regularity and mechanism of watershed environmental evolution about Sayram Lake, but also providing reference for the protection of regional ecological environment and decision reference for the protection of ecological security in the watershed. Meanwile the study is conducive to enrich and improve the ecological environment database of mountain lakes in the Tianshan Mountains, providing reference for the environmental management and planning of mountain lakes and watersheds in arid area. The main results are summarized as follows: Firstly, based on measured data, we studied the change trend of temperature and precipitation in recent 50 years in Sayram Lake basin using Mann-Kendall mutation test method and wavelet analysis. The average temperature takes on a significant rising trend. The abrupt change of annual mean temperature was came up in 1996. The annual mean temperature had three obvious periodic oscillations, in 6, 13 and 28 year. Annual precipitation is a significant fluctuation in the rising trend. The year of 1986 is an precipitation mutation year. The annual mean precipitation also had obvious periodic oscillations, which were 28, 21, 12 and 5 year. Secondly, after pretreatment, we used supervised classification method to deal with remote sensing image. During 1990-2015, the area of the grassland, woodland and glacier snow had decreased, but in degraded grassland had increased. Thirdly, the organic carbon and total nitrogen of topsoil samples in Sayram basin were analyzed, the study found that correlation between them is high. As different topsoil organic carbon and total nitrogen content in different vegetation, grassland topsoil organic carbon and total nitrogen content coverage of low vegetation is significantly lower than the high vegetation coverage of grassland and coniferous forest. Finally, we discussed the influence factors of topsoil carbon and nitrogen content. Fourthly, we used the organic indexes of sediment from Sayram Lake, including total nitrogen, pigment, the total organic carbon and its isotope, in combination with the environmental significance of sediment organic indexes, to reveal environmental information contained in organic matter. The change of the total organic carbon and total nitrogen content in Sayram Lake sediment indicated the lake productivity fluctuation; The change of pigment indicated the preservation conditions of organic matter, indirectly indicated water-heat allocation of lake-watershed; Organic carbon isotope reflected the lake mixture information of internal and external source. Combined with the orderly sample clustering analysis, Sayram lake environment evolution can be divided into four stages.
学科领域自然地理学
语种中文
文献类型学位论文
条目标识符http://ir.xjlas.org/handle/365004/14726
专题研究系统_荒漠环境研究室
作者单位中科院新疆生态与地理研究所
推荐引用方式
GB/T 7714
陈京. 赛里木湖流域表土及沉积物中有机质环境信息研究[D]. 北京. 中国科学院大学,2016.
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