Further discussion about the features of Lake Puma Yum Co, South Tibet, China

Abstract

Further discussion about the limnological features of Lake Puma Yum Co, South Tibet, China, is provided based on the results of several investigations. By using depth data from all over the lake, the whole submarine topography has been compiled. Horizontal analysis of the water's physicochemical features indicates that compared with the relatively uniform water features at other lake areas, apparent spatial heterogeneity exists in the water of the subaquatic alluvial fan induced by the Jiaqu River, the biggest inflow. Vertical analysis of water characteristics using two-factor analysis of variance with no reexperiment indicates that temperature, dissolved oxygen, and pH of the water vary with water depth rhythmically, whereas other parameters demonstrate no evident vertical variation, which shows that chemical stratification is not obvious. But this does not exclude slightly higher concentrations of Ca 2? induced by lower pH at the bottom of deep lake water. The hydrochemistry difference between inflow water and lake water reveals the loss of Ca 2? in lake water, which indicates calcite deposition may be an important characteristic of lake sediment.

Comparisons between the chemical compositions of lake water, inflowing river water, and lake sediment in Nam Co, central Tibetan Plateau, China and their controlling mechanisms

“…Water chemistry investigations had been conducted on various water bodies on the south side of Himalaya (e.g., Jenkins et al, 1995;Tartari et al, 1998;Hasnain and Thayyen, 1999;Das and Dhiman, 2003;Bhatt et al, 2007) while, in the inland area of the Plateau, comprehensive investigations have been carried out only on Qinghai Lake, the largest (about 4400 km 2 ) lake on the Plateau (LIGCAS, 1979). More recently, lake surveys were conducted of Pumoyum Co (Co means lake in the local Tibetan language), with the main purpose of obtaining a basic understanding of the processes driving its water and sediment chemistry; these understandings could then contribute to paleoenvironmental change studies (Mitamura et al, 2003;Murakami et al, 2007;Ju et al, 2010;Zhu et al, 2010b). For most other Tibetan lakes and rivers, only preliminary and sporadic information of water chemistry is available (e.g., Guan et al, 1984;Kawashima and Nishiyama, 1989;Zhou, 1998;Li et al, 1998;Chen et al, 2001).…”

Hydrochemical regime and its mechanism in Yamzhog Yumco Basin, South Tibet

“…The hydrochemistry of waters in the TP have been widely analyzed recently (Zhang et al, 2008;Zheng and Liu, 2009;Xiao et al, 2012a;Jiang et al, 2015;Tian et al, 2015;Yao et al, 2015;Wu, 2016). With respect to the Yamzhog Yumco Basin (YYB), significant achievements have been made on hydrochemical environment and its spatial variation (Chen, 1990;Zhu et al, 2010a;Sun et al, 2012a), as well as the chemical ions and its control factors (Zheng et al, 2008;Zhu et al, 2010b;Sun et al, 2012b). While limited by the harsh field conditions, previous observation records lasting for one year or a few months were insufficient for disclosing the long-term hydrochemical characteristics of alpine lakes.…”

A high-resolution environmental change record since 19 cal ka BP in Pumoyum Co, southern Tibet

“…According to the vertical distribution of water temperature in Pumoyum Co [28], wave base in the lake was less than 20 m. Sediments found at depths greater than 20 m were dominated by silt-clay (<63 m) [29] and were less influenced by lake wave re-sedimentation. Thus, fine sands and extremely fine sands (> 63 m) mainly were distributed in shallow water environments.…”