青藏高原现代湖泊介形虫组合及与环境因子的多元统计分析

A great number of lakes with various hydrochemistry properties distribute on the Tibetan Plateau with special geographical position and natural environment. Ostracods inhabiting in these lakes usually have special ecological or morphological characteristic, such as diverse species compositions, sizes, sex ratios and so on, which are significantly different from its distribution in other regions. It is a potent biologic indicator of palaeoenvironment. However, the ecological significance of most species is still unclear. For example, Limnocythere inopinata, widely distributed in most type of water bodies, is mainly regarded as a parthenogenesis species. However, quite abundant male valves of Limnocythere inopinata with high retio of male to female are recorded in lakes from interior region of Tibetan Plateau based on our investigation. Meanwhile, some species were found first time on the Tibetan Plateau with regional distribution feature. Besides, whether the existence or absence of tubercle can be an basis for identification remains debates. Therefore, Research on the ostracod species distribution in the lakes with various type in this region will not only enhance understanding on ecological features of ostracod, but also clear and definite the environmental factors impact on ostracod assemblages, which are benefit to the regional palaeoenvironment reconstruction. This study will focus on the surface sediment from 100-200 water bodies with various hydrochemistry properties in central-western Tibetan plateau, such as lake, river and swamp and so on. Meanwhile, the living ostracod, surface samples with different water depth and water samples will be collected from Longmu Co, Bangong Co, Siling Co and Heihai Lake. Based on the sediment, living ostracod identification, shell trace element and hydrochemical analysis, the ostracod assemblages and characteristic will be investigated and the ostracod assemblage response to lake environment will be determined. The major influence factor on the application of ostracod-based transfer functions will be discussed as well.

具有独特地理特征的青藏高原分布有大量不同水化学性质的湖泊，生活有较多种属的介形虫，是该地区强有力的古环境生物指标。研究表明青藏高原湖泊中介形虫独具特色，但绝大多数介形虫的生态意义仍不清楚。因此，对青藏高原湖泊中现生介形虫种属的区域性研究，不仅可以加深对介形虫种属生态特征的认识，而且能明确环境因子对介形虫种属的影响，利于对该地区古环境重建。本项研究选择青藏高原中西部地区的100-200个左右不同化学类型湖泊、河流、水洼，及龙木错、班公错、色林错、黑海不同深度表层沉积物中的介形虫，以及对采样点水样、湖泊中活体介形虫进行种属鉴定和壳体元素、水化学分析，了解青藏高原现代湖泊环境中介形虫种属类型及生态特征，明确研究区介形虫种属组合与湖泊环境介质的响应，探讨利用介形虫进行环境转换函数建立时的主要影响因素。

具有独特地理特征的青藏高原分布有大量不同水化学性质的湖泊，生活有较多种属的介形虫，是该地区强有力的古环境生物指标。研究表明青藏高原湖泊中介形虫独具特色，但绝大多数介形虫的生态意义仍不清楚。因此，对青藏高原湖泊中现生介形虫种属的区域性研究，不仅可以加深对介形虫种属生态特征的认识，而且能明确环境因子对介形虫种属的影响，利于对该地区古环境重建。项目执行期内，选择了青藏高原中西部地区的171个不同化学类型湖泊、河流、水洼，及黑海不同深度表层沉积物中的介形虫，以及对采样点水样、湖泊中活体介形虫进行种属鉴定和壳体元素、水化学分析，了解青藏高原现代湖泊环境中介形虫种属类型及生态特征，明确研究区介形虫种属组合与湖泊环境介质的响应。对冬给错纳湖北岸的湖岸阶地进行了矿物学、沉积学、微体古生物和地球化学指标的综合分析。利用矿物和介形虫对水体盐度的较好指示，认识冬给错纳湖湖面全新世以来的波动历史，从而深入了解高原东北部全新世以来的古季风演变过程。通过AMS 14C测年、沉积物粒度、总有机质含量、元素及生物标志化合物的分析，研究了定西鲁家沟早全新世太阳活动与水-热变化响应的河湖相-风成砂韵律记录。通过对海拔高度在2500-4500 m的甘肃南部和祁连山、青海东部、西藏东部林中表土、林间表土、森林上限表土、森林下限表土、森林上限高山草甸土，以及青海玉树冬给错纳地区亚高山荒漠--草甸土中可溶有机质正构烷烃分析，利用检测出的类异戊二烯烃的分布特征，对Pr（姥鲛烷）、Ph（植烷）的成因特征进行研究。对毛乌素沙漠南缘米浪沟湾地层(位于沙漠-黄土过渡带萨拉乌苏河流域)沉积物粒度、总有机碳(TOC)、碳酸盐碳氧同位素组成以及有机分子化合物正构烷烃进行了分析，探讨了末次冰期MIS 2阶段沙漠-黄土过渡带萨拉乌苏河流域环境演变记录。