Quantitative reconstruction of lake conductivity in the Quaternary of the Near East (Israel) using ostracods
Quantitative reconstruction of lake conductivity in the Quaternary of the Near East (Israel) using ostracods
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DOI：
10.1007/s10933-009-9359-y
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发表时间：
2010-04
影响因子：
2.1
通讯作者：
S. Mischke;A. Almogi‐Labin;R. Ortal;A. Rosenfeld;M. Schwab;I. Boomer
中科院分区：
文献类型：
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作者：
S. Mischke;A. Almogi‐Labin;R. Ortal;A. Rosenfeld;M. Schwab;I. Boomer
对以色列37个湖泊、池塘和溪流的表层沉积物、水样和环境数据进行了分析，以确定控制介形虫物种分布的主要变量。多元统计分析表明，宿主水体δD值(12.9%)、水温(11.0%)、1月平均气温(10.5%)、电导率(9.5%)、镁和硝酸盐浓度(7.8%和7.1%，离子浓度占阴阳离子的百分比)对介形类类群分布的影响最大。以前的研究提供了一个补充数据集，其中包括24个水体的介形虫种类组成和电导率读数，并将其与37个样本的数据集合并，以开发基于介形虫的传递函数，用于电导率的重建。加权平均偏最小二乘回归(WA-PLS)提供了最好的结果，通过对56个水体的留一法交叉验证，电导率实测值和推测值之间的决定系数(R2)相对较高，决定系数(R2)为0.73，预测均方根误差为0.13(梯度长度的13.4%)，最大偏差为0.24(梯度长度的23.9%)。EC传递函数应用于全新世和早、中更新世湖泊沉积物中的(亚)化石介形类组合，提供了与其他指标一致的EC值，并表明来自水下沉积物的第四纪介形类组合现在可以用来追踪近东水体的水文历史。在面临水资源有限和快速气候和环境变化时期需求上升的区域，更好地了解过去的水文状况以应对自然气候的变化至关重要。
Surface sediments, water samples and environmental data from 37 lakes, ponds and streams in Israel were analysed to determine the main variables controlling ostracod species distributions. Multivariate statistical analysis revealed that the greatest amounts of variation in the distribution of the ostracod taxa among the 37 water bodies were explained by the host water δD value (12.9%), water temperature (11.0%), mean January air temperature (10.5%), electrical conductivity (9.5%), and the Mg and NO3concentrations (7.8 and 7.1%, ion concentrations as % of the anions or cations). A supplementary data set comprising ostracod species composition and electrical conductivity readings for 24 water bodies was available from previous research and was merged with the 37 samples data set to develop an ostracod-based transfer function for the reconstruction of electrical conductivities. A weighted averaging partial least squares regression (WA-PLS) provided the best results with a relatively high coefficient of determination (r2) between measured and inferred electrical conductivity values of 0.73, a root mean square error of prediction of 0.13 (13.4% of gradient length) and a maximum bias of 0.24 (23.9% of gradient length), as assessed by leave-one-out cross-validation based on 56 water bodies. The application of the EC transfer function onto (sub)fossil ostracod assemblages from Holocene and early to mid Pleistocene lake sediments provided EC values consistent with other proxies and demonstrated that Quaternary ostracod assemblages from subaqueous sediments can now be used to trace the hydrological history of water bodies in the Near East. A better understanding of past hydrological conditions in response to the natural climate variability is crucial in regions that face restricted water resources and rising demands in times of rapid climate and environmental change.