biomarker,n-alkanes,environmental evolution; Holocene,Dalai Nur Lake,Inner Mongolia ,"/> <p class="MsoNormal"> <b>Environment Evolution and Its Response to Climate Change in the Dalai Nur Lake Area in the Last 2 400 Years</b>

Arid Zone Research ›› 2019, Vol. 36 ›› Issue (5): 1092-1101.doi: 10.13866/j.azr.2019.05.05

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Environment Evolution and Its Response to Climate Change in the Dalai Nur Lake Area in the Last 2 400 Years

LIU Jing-jing, ZHANG Sheng, LI Wen-bao, SHI Xiao-hong, XU Qiong, ZHEN Zhi-lei   

  1. Inner Mongolia Key Laboratory of Water Resources Protection and Utilization, Inner Mongolia Agricultural University, Hohhot 010018, Inner Mongolia,China
  • Received:2018-12-25 Revised:2019-03-14 Online:2019-09-15 Published:2019-09-11

Abstract:

In this paper, the Dalai Nur Lake (named DL-1) located in the northern marginal zone of the East Asian summer monsoon was taken as the research object. Through collecting, testing and analyzing the sediment core samples, the environmental evolution and its response to climate change in the Dalai Nur Lake area in the last 2400 years were discussed using n-alkanes and related indicators. The results showed that the carbon number distribution of n-alkanes in the sediment of Dalai Nur Lake varied in a range of C17~C33. In which the curve of C25 distribution was unimodal and its proportion accounted for 57% of the total samples; the curves of C19 and C25 distribution were bimodal and their proportion accounted for 30 %; the curves of C25 and C27 distribution were bimodal and their proportion accounted for 13 %. The change of the index parameters of n-alkanes revealed that the environmental evolution in the Dalai Nur Lake region was not only consistent with the global climate events, but also affected by the changes of precipitation in East Asian summer monsoon and of cold-warm events in the lake region over the past 2400 years. The climate change could be divided into six stages. Stages 1, 3 and 5 (75 a BP-present, 985-600 a BP and 2180-1550 a BP) were the warm-humid climatic stages. At these stages, the effective humidity in the lake area was high, woody plants were dominant, aquatic plants grew vigorously, and the nutrient status of the lake was fine. Stages 2, 4 and 6 (600-75 a BP, 1550-985 a BP and 2355-2180 a BP) were the cold-dry climatic stages. At these stages, bacterial algal reproduction was fast, the proportion of herbaceous plants increased, and the primary productivity of the lake was lower. Overall, climate change in the Dalai Nur Lake area changed from warm-humid pattern to cold-dry pattern over the past 2400 years.

Key words: biomarker')">

biomarker, n-alkanes, environmental evolution; Holocene, Dalai Nur Lake, Inner Mongolia