Vertical micro-distribution of microbial communities living in Sphagnum fallax

Distributions of microbial communities living along a close vertical gradient in a Sphagnum fallax peatland were studied. Samples were collected from the top 6 cm of sphagnum moss at intervals of 0-0.5, 0.5-1, 1-2, 2-3, 3-4, 4-5, and 5-6 cm. Different microbial trophic groups, primary producers (microalgae and cyanobacteria), consumers (ciliates, heterotrophic flagellates, testate amoebae, rotifers and nematodes) and decomposers (fungi and bacteria) were examined. There was no significant difference in the total vertical microbial biomass. However, the biomass of ciliates and rotifers significantly decreased with depth, while the biomass of fungi and bacteria significantly increased. Testate amoebae biomass showed a similar vertical distribution, but strong and significant species-specific variations were observed. Cluster analysis organized the microbial community from the top 6 cm of sphagnum moss into 3 layers: capitula (0-1 cm), dominated by mixotrophic consumers (mixotrophic ciliates and testate amoebae); green stems (1-3 cm), characterized by microbial primary producers; and litter (3-6 cm), dominated by heterotrophic consumers and decomposers. These results highlight the potential of using these layers to better describe microbial communities in S. fallax.