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利用活塞取样器在藏南沉错获取了连续的沉积岩芯,选择顶部的117cm岩芯段进行水蚤(Cladocera)残体分析.根据水蚤的种类、数量和生态习性,从下到上可以将岩芯中水蚤组合划分为5个带:CL0组合(117～101cm)没有发现水蚤;CL1组合(101～77cm,约公元1407～1533年)出现钻孔中的全部9种水蚤,并达到序列中的最高含量,反映了在温暖的沉积环境中有大量的外来冷水注入和有机质输入,湖泊宽浅适宜大型水生植物的生长;CL2组合(77～29cm,约公元1533～1831年)的水蚤数量和种类大大下降,只有为数不多、环境适应性较强的Chydorussphaericus经常存在,说明了当时的沉积环境非常恶劣;CL3组合(29～10cm,约公元1831～1941年)的优势水蚤种类与CL1组合接近,但丰度下降,特别是喜有机碎屑环境的水蚤数量大大降低,反映了环境有利的条件下,流域地表的植被发育仍然较差;CL4组合(10～0cm,约公元1941年到现在)除没有发现浮游型水蚤外,其他7种水蚤均可见到,稳定的湖泊水温使广温型的水蚤种与窄温型的浅水种相比,已经失去竞争优势.该孔水蚤组合反映的环境变化得到其平行孔的介形类组合、环境磁学与相关参数以及硅藻-盐度转换函数研究结果的支持,反映了青藏高原湖泊沉积中的水蚤组合对沉积环境的敏感性和在环境变化研究中的重要意义.
A continuous sedimentary core was obtained using a piston sampler in the south of Tibet, and the top 117cm core segment was selected for Cladocera debris analysis. Depending on the species, number and ecological habits of the daphnids, Daffodil assemblages in the core were divided into five zones: no Daphnia was found in the CL0 combination (117-101 cm); all nine Daphnia in boreholes appeared in the CL1 combination (101-77 cm, circa 1407-1533 AD) Reaching the highest content in the sequence, reflecting the large amount of external cold water injection and organic matter input in a warm sedimentary environment and the broadness of lakes suitable for the growth of large aquatic plants; the CL2 combination (77-29 cm, ca 1533-1831) The abundance and species of daphnids declined greatly. Only a few Chydorussphaericus, which are often found in the environment, showed that the sedimentary environment was very poor at that time. The dominance of Daphnia magna (29-10 cm, about 1831-1941) However, the abundance of Daphnia magna was significantly lower than that of CL1. Especially, the number of Daphnia in organic-like debris environment was greatly reduced, which reflected that the vegetation on the surface of the basin was still poorly developed under favorable conditions. CL4 (10 ~ 0cm, about AD 1941 to the present) In addition to the discovery of planktonic water fleas, the other seven kinds of daphnia can be seen, the stable lake water temperature so wide-type water flea species and narrow temperature shallow species has lost the competitive advantage of the Kong daphnia combination The changes of the environment reflected by the colony of their parallel pores are supported by the results of environmental magnetism and related parameters and the results of diatom-salinity transfer function, which reflect the sensitivity of the Daphnia group to sedimentary environment in the lake sediments of the Qinghai-Tibet Plateau And its significance in the study of environmental change.