open access

https://hdl.handle.net/2115/39477

Community structure of microorganisms associated with reddish-brown iron-rich snow

英語

Snow coverage

2009-09

Elsevier GmbH

Systematic and Applied Microbiology

32(6)

429-437

Reddish-brown colored snow, containing spherical brown particles, is observed in several mires in Japan. In order to characterize this remarkable phenomenon, the microbial community and chemical species in snow were analyzed. A core sample of snow which had colored region was investigated to reveal vertical shifts in physicochemical characteristics and the microbial community structure. The abundance of particle peaked within the colored layer, and correlated with the amount of reducible Fe(III). The interstitial water of colored layer was enriched with Fe(II), and characterized by reduced concentration of dissolved methane. The bacterial community in the colored region was characterized by higher relative abundance of iron-reducing bacteria and methanotrophs. Aggregates of the brown particles were found as precipitates in snow melt pools, and subjected to cloning analyses targeting several different genes. The majority of bacterial 16S rRNA gene clones belonged to the class Betaproteobacteria or the phylum Bacteroidetes. No snow algae were detected in the eukaryotic small subunit rRNA gene clone library. As a possible carbon source to sustain the community in the snow, involvements of carbon dioxide and methane were investigated by analyzing the genes involved in assimilation of these. In the analyses of genes for ribulose-1,5-biphosphate carboxylase/oxygenase, clones related to sulfur oxidizers were obtained. The analysis or particulate methane monooxygenase genes indicated dominance of Methylobacter species. These results emphasized the uniqueness of this phenomenon, and iron reducers of the genus Geobacter are suggested to be the key organisms that can be investigated to understand the mechanism of this phenomenon.

学術雑誌論文

Accepted Manuscript

0723-2020