上冰川池普遍存在于碎片覆盖的高山冰川上,然而,关于这些栖息地内微生物群落的信息有限。我们对这项初步研究的研究问题是:(1)西藏季风上冰川池沉积物中存在哪些微生物?(2)哪些非生物和生物栖息地变量对微生物群落结构的影响最大?(3)上冰川池沉积物的微生物组成是否与冰川-融化流池沉积物不同?我们从2018年的9个冰川池和无脊椎动物池中收集了16SrRNA测序和无脊椎动物的微生物样本,以进行计数和鉴定。广义线性模型分析,小样本Akaike信息准则,和变量重要性评分用于确定微生物群落结构的最佳预测变量。多反应排列程序(MRPP)用于比较上泪池和溪流池之间的分类单元组成。冰上池沉积物中最丰富的门是变形杆菌,放线菌,拟杆菌,氯氟菌,和蓝细菌。属丰富,指示属丰富度,Chironomidae幼虫的丰度最好地预测了Polaromonas的相对丰度。Angustibacter和Oryzihumus的相对丰度最好通过pH来预测,嗜酸杆菌的相对丰度最好通过浊度来预测,鞘氨醇单胞菌的相对丰度最好用冰川带预测。分类群的组成在班上和溪流池之间相似,属,和ASV分类水平。我们的结果表明,Chironomidae幼虫可能在形成碎片覆盖的冰川上冰川上池的细菌群落中起关键作用。重要冰川融水栖息地(冰冻洞穴,上冰川池,湖上池塘和湖泊,冰川流)及其生物群尚未得到充分研究,特别是在温带季风地区被碎片覆盖的冰川上。我们的研究是第一个记录了西藏碎片覆盖的冰川上冰川池的微生物群落与栖息地关系的研究。微生物属丰富度,指示属丰富度,和Polaromonas相对丰度随着幼虫Chironomidae丰度的增加而下降,这是一个新的发现,强调了幼虫昆虫在构建上泪池微生物群落中的重要性。
Supraglacial pools are prevalent on debris-covered mountain glaciers, yet only limited information is available on the microbial communities within these habitats. Our research questions for this preliminary study were: (1) What microbes occur in supraglacial pool sediments of monsoonal Tibet?; (2) Which abiotic and biotic habitat variables have the most influence on the microbial community structure?; and (3) Does microbial composition of supraglacial pool sediments differ from that of glacial-melt stream pool sediments? We collected microbial samples for 16S rRNA sequencing and invertebrates for enumeration and identification and measured 14 abiotic variables from 46 supraglacial pools and nine glacial-melt stream pools in 2018 and 2019. Generalized linear model analyses, small sample Akaike information criterion, and variable importance scores were used to identify the best predictor variables of microbial community structure. Multi-response permutation procedure (MRPP) was used to compare taxa composition between supraglacial pools and stream pools. The most abundant phyla in supraglacial pool sediments were Proteobacteria, Actinobacteria, Bacteroidota, Chloroflexi, and Cyanobacteria. Genera richness, indicator genera richness, and Polaromonas relative abundance were best predicted by
Chironomidae larvae abundance. Angustibacter and Oryzihumus relative abundance were best predicted by pH, Acidiphilium relative abundance was best predicted by turbidity, and Sphingomonas relative abundance was best predicted by glacier zone. Taxa composition was similar between supraglacial and stream pools at the class, genus, and ASV taxonomic levels. Our results indicate that
Chironomidae larvae may play a keystone species role in shaping bacterial communities of supraglacial pools on debris-covered glaciers.IMPORTANCEGlacier meltwater habitats (cryoconite holes, supraglacial pools, supraglacial ponds and lakes, glacial streams) and their biota have not been well-studied, especially on debris-covered glaciers in temperate monsoonal regions. Our study is the first to document the microbial community-habitat relationships in supraglacial pools on a debris-covered glacier in Tibet. Microbial genera richness, indicator genera richness, and Polaromonas relative abundance declined with increasing larval
Chironomidae abundance, which is a novel finding that highlights the importance of larval insects in structuring microbial communities in supraglacial pools.