Distant glacial areas are interconnected by a complex system of fractures and water channels which run in the glacier interior and characterize the englacial realm. Water can slowly freeze in these channels where the slow freezing excludes air bubbles giving the ice a clear aspect. This ice is uplifted to the surface ablation zone by glacial movements and can therefore be observed in the form of clear surface ice bands. We employed an indirect method to sample englacial water by coring these ice bands. We were able, for the first time, to compare microbial communities sampled from clear (i.e. frozen englacial water bands) and cloudy ice (i.e. meteoric ice) through 16S rRNA gene sequencing. Although microbial communities were primarily shaped and structured by their spatial distribution on the glacier, ice type was a clear secondary factor. One area of the glacier, in particular, presented significant microbial community clear/cloudy ice differences. Although the clear ice and supraglacial communities showed typical cold-adapted glacial communities, the cloudy ice had a less defined glacial community and ubiquitous environmental organisms. These results highlight the role of englacial channels in the microbial dispersion within the glacier and, possibly, in the shaping of glacial microbial communities.

中文翻译：

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冰川清晰的冰带表明冰川通道微生物分布

遥远的冰川区域通过复杂的裂缝和水道系统相互连接，这些裂缝和水道在冰川内部运行，是冰川领域的特征。水可以在这些通道中缓慢冻结，其中缓慢冻结排除了气泡，使冰具有清晰的外观。这些冰被冰川运动抬升到地表消融区，因此可以以清晰的地表冰带的形式观察到。我们采用间接方法通过对这些冰带进行取芯来取样冰河水。我们第一次能够通过 16S rRNA 基因测序比较从清澈（即冰冻的冰川水带）和多云冰（即大气冰）中取样的微生物群落。尽管微生物群落主要是由它们在冰川上的空间分布形成和构造的，但冰类型是一个明显的次要因素。特别是冰川的一个区域呈现出显着的微生物群落清晰/多云冰差异。虽然清冰和冰上群落显示出典型的冷适应冰川群落，但云冰的冰川群落不太明确，环境生物无处不在。这些结果突出了冰川通道在冰川内微生物扩散中的作用，以及可能在冰川微生物群落形成中的作用。