Chinanews.com, Coqin County, Tibet, July 27th (Reporter Sun Zifa) China's second comprehensive scientific expedition to the Qinghai-Tibet Plateau (Second Qinghai-Tibet Scientific Expedition) "The History of Human Activities and Its Impact" scientific expedition team, completed on July 26 The third largest lake in the Tibet Autonomous Region-the hydrological and ecological survey work in Zhari Nanmu Co at an altitude of 4613 meters in Coqin County, Ngari Prefecture.
Before and during this period, the scientific expedition team also sent expedition teams to Laguocuo in Gaize County (4,500 meters above sea level) and Angucuo in Cuoqin County (4600 meters above sea level) to collect surface soil samples in these two lake basins. Task.
The scientific expedition team returned from an inflatable speedboat to investigate Zharinam.
Photo by China News Agency reporter Sun Zifa
He Yue, a member of the scientific expedition team and associate professor of the School of Earth Sciences of Hebei University of Geosciences, said that Zari Nanmu Co is the third largest lake in Tibet. It is an east-west tectonic faulted lake. The lake has an elevation of 4613 meters and a maximum water depth of 71.55 meters. It is far from Coqin. The county seat is about 12 kilometers. It is a plateau lake with a length of about 54 kilometers from east to west, a width of about 20 kilometers from north to south, and an area of about 1,023 square kilometers.
The most prominent feature of Zharinamcu is the obvious development of ancient lakeshore sandbanks. The highest level of ancient lakeshore sandbanks is nearly 100 meters higher than the current lake surface. Such drastic lake changes indicate that Zharinamcu has a sensitive response to climate change. .
He Yue said that the scientific expedition team's current research on Zari Namcu is mainly carried out from three levels: First, thermometers are placed at different depths in the lake to monitor the changes in water temperature. This is a long-term basic work that is conducive to understanding. The hydrological characteristics of Zharinam Co, monitoring its response to climate change.
The second is that the scientific expedition team collects surface sediments from the Zharinan Muco Lake every year to update and supplement the existing sample library of surface sediments from lakes on the Qinghai-Tibet Plateau.
There are many lakes on the Qinghai-Tibet Plateau with rich types and significant differences. The content of specific biomarker compounds in the surface sediments of different lakes and their correlation with environmental factors (such as temperature, salinity, pH, etc.) can be analyzed and tested. Researchers can establish this The conversion equations between compounds and environmental factors are then used to reconstruct past environmental changes.
The third is to use gravity drill samplers to collect cores from the bottom of the Zharinam Co Lake with a depth of about 1 meter, which may represent the sedimentary records of the past thousands of years. Using the conversion equation between the content of biomarkers and environmental factors mentioned above, the local past few years can be reconstructed. Environmental changes in the millennium and discuss their impact mechanisms.
He pointed out that due to the heavy wind and waves on the lake in Zhari Nam Co on the 26th, the expedition team members took an inflatable speedboat to investigate the hydrology and ecology on the lake for nearly two hours. For safety reasons, they did not read the thermometer in the lake. Sampling work at the bottom of the lake was decided to be implemented later.
The scientific expedition team collected scientific research samples on the shore of Lake Laguocuo.
Photo by China News Agency reporter Sun Zifa
Hou Xiaohuan, a member of the scientific expedition team and a doctoral student from the Institute of Tibetan Plateau Research, Chinese Academy of Sciences, went to Laguo Co and Anggu Co on the 25th and 26th to collect surface soil samples from the lake basin. Nearly 30 surface soil samples were collected at intervals of 1 to 2 kilometers along the lake. .
Hou Xiaohuan said that the use of lake-related indicators to reconstruct past climate and environmental changes on the Qinghai-Tibet Plateau must carry out a modern process study of indicators, which requires researchers to collect surface soil and lake surface sediment samples in lake basins to analyze the relationship between indicators and modern climate elements. In this way, the past climate and environmental changes on the Qinghai-Tibet Plateau can be reconstructed more accurately.
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