Uetake Jun, Tanaka Sota, Segawa Takahiro, Takeuchi Nozomu, Nagatsuka Naoko, Motoyama Hideaki, Aoki Teruo
Transdisciplinary Research Integration Center, Minatoku, Tokyo 105-0001, Japan National Institute of Polar Research, Tachikawa, Tokyo 190-8518, Japan
Graduate School of Science, Chiba University, Inageku, Chiba 263-8522, Japan.
FEMS Microbiol Ecol. 2016 Sep;92(9). doi: 10.1093/femsec/fiw127. Epub 2016 Jun 14.
Cryoconite granules are aggregations of microorganisms with mineral particles that form on glacier surfaces. To understand the processes by which the granules develop, this study focused on the altitudinal distribution of the granules and photosynthetic microorganisms on the glacier, bacterial community variation with granules size and environmental factors affecting the growth of the granules. Size-sorted cryoconite granules collected from five different sites on Qaanaaq Glacier were analyzed. C and N contents were significantly higher in large (diameter greater than 250 μm) granules than in smaller (diameter 30-249 μm) granules. Bacterial community structures, based on 16S rRNA gene amplicon sequencing, were different between the smaller and larger granules. The filamentous cyanobacterium Phormidesmis priestleyi was the dominant bacterial species in larger granules. Multivariate analysis suggests that the abundance of mineral particles on the glacier surface is the main factor controlling growth of these cyanobacteria. These results show that the supply of mineral particles on the glacier enhances granule development, that P. priestleyi is likely the key species for primary production and the formation of the granules and that the bacterial community in the granules changes over the course of the granule development.
冰尘颗粒是微生物与矿物质颗粒的聚集体，形成于冰川表面。为了解这些颗粒的形成过程，本研究聚焦于冰川上颗粒和光合微生物的海拔分布、颗粒大小与细菌群落变化以及影响颗粒生长的环境因素。对从卡纳克冰川五个不同地点收集的按大小分类的冰尘颗粒进行了分析。大颗粒（直径大于250μm）中的碳和氮含量显著高于小颗粒（直径30 - 249μm）。基于16S rRNA基因扩增子测序的细菌群落结构在小颗粒和大颗粒之间存在差异。丝状蓝细菌普氏原绿球藻是大颗粒中的优势细菌物种。多变量分析表明，冰川表面矿物质颗粒的丰度是控制这些蓝细菌生长的主要因素。这些结果表明，冰川上矿物质颗粒的供应促进了颗粒发育，普氏原绿球藻可能是初级生产和颗粒形成的关键物种，并且颗粒中的细菌群落在颗粒发育过程中会发生变化。
