Temporary Survival Increasing the Diversity of Culturable Heterotrophic Bacteria in the Newly Exposed Moraine at a Glacier Snout

Yang Liu; Yeteng Xu; Xiaowen Cui; Binglin Zhang; Xinyue Wang; Xiang Qin; Jinxiu Wang; Yanzhao Li; Wei Zhang; Guangxiu Liu; Tuo Chen; Gaosen Zhang

doi:10.3390/biology11111555

Temporary Survival Increasing the Diversity of Culturable Heterotrophic Bacteria in the Newly Exposed Moraine at a Glacier Snout

Biology (Basel). 2022 Oct 24;11(11):1555. doi: 10.3390/biology11111555.

Authors

Yang Liu^{1

2

3}, Yeteng Xu^{1

2

3}, Xiaowen Cui^{3

4

5}, Binglin Zhang^{1

2

3}, Xinyue Wang^{2

3

4}, Xiang Qin^{1

3}, Jinxiu Wang^{3

4}, Yanzhao Li^{1

2

3}, Wei Zhang^{3

4}, Guangxiu Liu^{3

4

6}, Tuo Chen¹, Gaosen Zhang^{3

4}

Affiliations

¹ State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
² University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
³ Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou 730000, China.
⁴ Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
⁵ College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, China.
⁶ School of Stomatology, Lanzhou University, Lanzhou 730000, China.

Abstract

Laohugou Glacier No. 12 is located on the northern slope of the western Qilian Mountains with a temperate continental wet climate and an extremely cold winter. Bacteria in a newly exposed moraine have to cope with various pressures owing to deglaciation at the glacier snout. However, limited information is available regarding the high diversity and temporary survival of culturable heterotrophic bacteria under various environmental stresses. To examine the tolerance of extremophiles against varying environmental conditions in a newly exposed moraine, we simulated environmental stress in bacterial cultures. The results showed that the isolated strains belonged to actinobacteria, Proteobacteria, Bacteroidetes, Deinococcus-Thermus, and Firmicutes. Actinobacteria was the most abundant phylum, followed by Proteobacteria, at both high and low temperatures. Pseudarthrobacter was the most abundant genus, accounting for 14.2% of the total isolates. Although several microorganisms grew at 10 °C, the proportion of microorganisms that grew at 25 °C was substantially higher. In particular, 50% of all bacterial isolates grew only at a high temperature (HT), whereas 21.4% of the isolates grew at a low temperature (LT), and 38.6% of the isolates grew at both HT and LT. In addition, many radiation-resistant extremophiles were identified, which adapted to both cold and oxidative conditions. The nearest neighbors of approximately >90% of bacteria belonged to a nonglacial environment, such as oil-contaminated soil, rocks, and black sand, instead of glacial niches. This study provides insights into the ecological traits, stress responses, and temporary survival of culturable heterotrophic bacteria in a newly exposed moraine with variable environmental conditions and the relationship of these communities with the non-glacial environment. This study may help to understand the evolution, competition, and selective growth of bacteria in the transition regions between glaciers and retreats in the context of glacier melting and retreat owing to global warming.

Keywords: Laohugou Glacier No. 12; culturable; extremophiles; glacier snout; heterotrophic bacteria; temporary survival.

Grants and funding

This research was supported by the National Key Research and Development Program of China (2019YFE0121100), the National Natural Science Foundation of China (41801045), and the Scientific Project of Gansu Province (20YF3WA007, 22JR5RA056, 20JR5RA548).