Microflorae of aquatic moss pillars in a freshwater lake, East Antarctica, based on fatty acid and 16S rRNA gene analyses

Ryosuke Nakai, Takashi Abe, Tomoya Baba, Satoshi Imura, Hiroshi Kagoshima, Hiroshi Kanda, Atsuko Kanekiyo, Yuji Kohara, Akiko Koi, Keiko Nakamura, Takanori Narita, Hironori Niki, Katsuhiko Yanagihara, Takeshi Naganuma

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


Aquatic mosses in the genera Bryum and Leptobryum form unique tower-like "moss pillars" underwater in some Antarctic lakes, in association with algae and cyanobacteria. These are communities with a two-layer structure comprising an oxidative exterior and reductive interior. Although habitats and photosynthetic properties of moss pillars have been reported, microfloral composition of the two-layer structure has not been described. Here we report fatty acid analysis of one moss pillar and molecular phylogenetic analysis, based on the 16S rRNA gene, of this and one other moss pillar. Cluster analysis of the phospholipid fatty acid composition showed three groups corresponding to the exterior, upper interior, and lower interior of the pillar. This suggested that species composition differed by section, with the exterior dominated by photosynthetic organisms such as mosses, algae, and cyanobacteria, the upper interior primarily containing gram-positive bacteria and anaerobic sulfate-reducing bacteria, and the lower interior dominated by gram-negative bacteria. Molecular phylogenetic analysis revealed that Proteobacteria dominate the moss pillar as a whole; cyanobacteria were found on the exterior and the gram-positive obligate anaerobe Clostridium in the interior, while gram-positive sulfate-reducing bacteria were present in the lowest part of the interior. Nitrogen-fixing bacteria and denitrifying bacteria were found in all sections. Thus, fatty acid analysis and genetic analysis showed similar patterns. These findings suggest that microorganisms of different phylogenetic groups inhabit different sections of a single moss pillar and form a microbial community that performs biogeochemical cycling to establish and maintain a structure in an oxidation-reduction gradient between exterior and interior.

Original languageEnglish
Pages (from-to)425-433
Number of pages9
JournalPolar Biology
Issue number3
Publication statusPublished - Mar 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Agricultural and Biological Sciences


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