Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.
Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.
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中国西北干旱区艾比湖沉积物对人为和自然影响的地球化学响应
DOI：
10.1371/journal.pone.0155819
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Liu W
中科院分区：
文献类型：
--
作者：
Ma L;Wu J;Abuduwaili J;Liu W
以艾比湖沉积物短柱样为研究对象，提取了艾比湖沉积物的地球化学元素含量，并利用数学方法研究了艾比湖沉积物地球化学异常的复杂模式。第一元素集合体（C1）（铝、钾、铁、镁、铍等）主要为陆源;其中，全磷、钛与铝的关系基本一致，但表层序列不同，推测陆源碎屑物源区的差异导致了这种变化。公元2000年第二个组合（C2）（钙和锶）被发现有负相关的铝通过聚类分析。第三个组合（C3）为钠、镁组合，受水下湖泊环境影响，沉积于艾比湖坳陷。C1/（C1+C2）浓度比可作为碎屑物质剥蚀量的指示因子，磁化率值支持这一观点。重金属的富集系数表明，艾比湖地区近世纪来人类活动对重金属富集的影响并不严重。在20世纪60年代之前，地球化学指标表明，湖泊环境稳定，水位较高。从20世纪60年代开始，农业用水需求量大导致湖水水位迅速下降，随后湖水盐度增加，湖泊核心沉积物中钠浓度增加就是证明。在此期间，人类活动也增加了艾比湖流域的风化和剥蚀强度。
Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.