Abstract
Cryoconites harbor diverse microbial communities and are the metabolic hotspot in the glacial ecosystem. Glacial ecosystems are subjected to frequent climate disturbances such as precipitation (snowing), but little is known about whether microbial communities in cryoconite can maintain stability under such disturbance. Here, we investigated the bacterial community in supraglacial cryoconite before and after a snowfall event on the Laohugou Glacier (Tibetan Plateau), based on Illumina MiSeq sequencing of the 16S rRNA gene. Our results showed that the diversity of the microbial community significantly decreased, and the structure of the microbial community changed significantly after the disturbance of snowfall. This was partly due to the relative abundance increased of cold-tolerant bacterial taxa, which turned from rare into abundant sub-communities. After snowfall disturbance, the contribution of the deterministic process increased from 38 to 67%, which is likely due to the enhancement of environmental filtering caused by nitrogen limitation. These findings enhanced our understanding of the distribution patterns and assembly mechanisms of cryoconite bacterial communities on mountain glaciers.
Highlights
Cryoconite is dark sediment deposited on the glacial surfaces, comprising both mineral and biological materials
The concentration of total organic carbon (TOC) and total carbon (TC) of samples after snowfalls were similar between the samples before and after snowfalls (Wilcoxon rank-sum test, P = 0.13, and P = 0.73, respectively)
Our results demonstrated that Total nitrogen (TN) significantly affected the bacterial community (Table 2)
Summary
Cryoconite is dark sediment deposited on the glacial surfaces, comprising both mineral and biological materials. Supraglacial cryoconite serves as a habitat for diverse microbial communities, including viruses, bacteria, fungi, archaea, algae, and invertebrates, which are responsible for the glacier biogeochemical cycling (Anesio et al, 2007, 2010; Edwards et al, 2011, 2013; Zarsky et al, 2013). Understanding the response of microbial communities to climate disturbance is essential for the study of ecosystem functions (Steudel et al, 2012). Microbial communities are affected by various physicochemical factors (Stibal et al, 2012; Cook et al, 2016; Anesio et al, 2017). Temperature and nutrient availability have been proposed to be the main factors controlling the microbial communities in polar and mountain glacier cryoconite
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