Department of Ecology, Faculty of Science, Charles University, Prague, Vinicna 7, 128 44 Prague 2, Czechia.
Department of Environment Sciences, Western Norway University of Applied Sciences, Royrgata 6, 6856 Sogndal, Norway.
FEMS Microbiol Ecol. 2018 Jul 1;94(7). doi: 10.1093/femsec/fiy100.
Microbes transported by glacial meltwater streams are thought to be a product of passive dispersal from both supra- and subglacial sources, though studies investigating the origins of these assemblages are scarce. Here, we conducted a survey within a large catchment containing multiple glaciers on Qeqertarsuaq (Disko Island), west Greenland, to investigate whether meltwater-exported microbial assemblages in suspended sediments differ between glacial meltwater streams, and if they reflect corresponding bulk subglacial and extraglacial sediment communities. Using 16S rRNA gene amplicon sequencing, we found proglacial stream assemblages substantially differ from one another, despite their close spatial proximity. Furthermore, proglacial stream assemblages were composed of greater proportions of Cyanobacteria compared to bulk subglacial sediment communities, dominated by Betaproteobacteria, demonstrating large contributions of meltwater and microbial cells from supraglacial habitats. Corresponding physico-chemical characteristics of meltwater suggest that streams draining smaller glaciers had more equal contributions of both supra- and subglacial inputs compared with the main catchment outlet, aligning with observed changes in assemblage structure, such as the decreased proportion of Cyanobacteria. These results suggest that glacier size and hydrological drainage systems may influence the structure of exported microbial assemblages, and collectively provide insights into their formation and fate in thiscurrent age of deglaciation.
冰川融水溪流携带的微生物被认为是来自冰上和冰下源的被动扩散的产物，尽管研究这些组合的起源的研究很少。在这里，我们在格陵兰岛西部的迪斯科岛的一个大流域内进行了一项调查，该流域包含多个冰川，以调查悬浮沉积物中融化水输出的微生物组合在冰川融水溪流之间是否存在差异，以及它们是否反映了相应的冰下和冰外沉积物群落。使用 16S rRNA 基因扩增子测序，我们发现尽管冰川融水溪流彼此靠近，但它们的前冰川溪流群落却有很大的不同。此外，与冰下沉积物群落相比，前冰川溪流群落中蓝细菌的比例更大，优势菌群为β变形菌门，表明来自冰上生境的融水和微生物细胞有很大的贡献。融化水的相应理化特性表明，与主要集水区出口相比，较小冰川的溪流具有更多的冰上和冰下输入的平等贡献，与群落结构的变化一致，例如蓝细菌的比例降低。这些结果表明，冰川大小和水文排水系统可能会影响输出微生物组合的结构，并共同深入了解它们在当前冰川消退时代的形成和命运。
