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Journal of Desert Research ›› 2020, Vol. 40 ›› Issue (4): 10-17.DOI: 10.7522/j.issn.1000-694X.2020.00012

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Characteristics of microcharcoal in the lake surface sediments in the northern margin of Qaidam Basin of China and its environmental significance

Zisha Wang1,2(), Yunfa Miao1,2(), Yongtao Zhao1, Fang Li1, Yan Lei1,2, Mingxing Xiang1,2, Yaguo Zou1,2   

  1. 1.Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2019-10-30 Revised:2020-01-20 Online:2020-08-20 Published:2020-09-01
  • Contact: Yunfa Miao

Abstract:

Microcharcoal in the surface sediments is of great significance in exploring the basic characteristics of fire and its relationship with vegetation and human activities. Here we analyzed the microcharcoal extracted with the pollen methodology from the surface sediments of lakes in the northern margin of Qaidam Basin to explore its spatial distribution and relationship with regional vegetation and modern human activities. Results showed that the microcharcoal concentration of different grain-size groups has a similarity trend of increasing from northwest to northeast of the basin, which can be coupled with the trend of increasing regional vegetation coverage from west to east. The microcharcoals with the small grain-size (<50 μm) are mostly in the shape of sub-round, which indicates that there is more woody vegetation burning in fires with longer distances. And the sub-long grains microcharcoal with large grain size (>50 μm) is dominant, indicating that the burning of herbaceous plants increased gradually to the east, which consistent with the distribution of herbaceous plants, and the distance from the fire to the sedimentary area of microcharcoal is reduced. Additionally, the population of this area also has a tendency to increase from west to east. Human activities also have a certain impact on the microcharcoal concentration, our analyses show that the microcharcoal concentration has a good correspondence with the population density. Therefore, the spatial variation characteristics of microchacoal in surface sediments not only reflect the fire information of the corresponding areas but also have a good indication for regional vegetation and human activities.

Key words: Qaidam Basin, microcharcoal, surface sediments, fire, vegetation, human activities

CLC Number: