Under the auspices of CAS within the program—study of environmental change and its influence on ecosystem on the Tibetan Plateau since Pleistocene, Prof. Zhu Liping, researcher from ITP and his Japanese cooperators succeeded in carrying out a field survey to Pumoyongcuo area in Tibet from 8th, September to the 20th this year.
The Pumoyongcuo area, south of Tibet autonomous region, measures 148 km as a water body and ca. 5030m above sea level. Some part of the lake is as deep as 70m. It is mainly supplied by precipitation and glacial melting all the year round. Since it is virgin to scientific exploration, scientists regard it to be the ideal type of lake to study lake sediment and environmental change on the plateau.
The joint field survey this time mainly focused on the following aspects:
1)Carrying out study of glacial supply and evolution of lakes and rivers for a thorough understanding of interior connection between lake basin sufface and water/sediment in the center of lake sediment;
2)looking into the effect of solar radiation on form, biophysics and ecological characters of creatures, studying the correlation between biological activities and solar UV, and recovering the mobile effect of plankton in form, biophysics and ecological activity;
3) investigating the lake and the flows in such aspects as physics, chemistry and biological parameter, including hydrology, transparency degree, conductive rate, pH, solubility, major factors, micro elements, nutrions, soluble organic factors, particle organic factors, pigment and so on;
4) selecting sediment samples from water and rock confines to conduct C, N, P and partical analysis, together with the circulation of biology and geochemistry of biochemical metabolism in the lake going on;
5) carrying out a series of measuring tasks to confirm the thickness of underwater sediment;
6) analyzing paleo-environmental change indicated in a number of proxies collected from sur-lake platform and other facilities.
After on spot survey and sampling, this expedition group not only drew out a detailed diagram of isodepth line for the entire lake, but also drilled a 3.9 lake core from the sediment center, 64m under the water, which is believed to be the longest from such giant lakes on the plateau.