Pyrosequencing-Based Assessment of the Bacteria Diversity in Surface and Subsurface Peat Layers of a Northern Wetland, with Focus on Poorly Studied Phyla and Candidate DivisionsReport as inadecuate




Pyrosequencing-Based Assessment of the Bacteria Diversity in Surface and Subsurface Peat Layers of a Northern Wetland, with Focus on Poorly Studied Phyla and Candidate Divisions - Download this document for free, or read online. Document in PDF available to download.

Northern peatlands play a key role in the global carbon and water budget, but the bacterial diversity in these ecosystems remains poorly described. Here, we compared the bacterial community composition in the surface 0–5 cm depth and subsurface 45–50 cm peat layers of an acidic pH 4.0 Sphagnum-dominated wetland, using pyrosequencing of 16 S rRNA genes. The denoised sequences 37,229 reads, average length ∼430 bp were affiliated with 27 bacterial phyla and corresponded to 1,269 operational taxonomic units OTUs determined at 97% sequence identity. Abundant OTUs were affiliated with the Acidobacteria 35.5±2.4% and 39.2±1.2% of all classified sequences in surface and subsurface peat, respectively, Alphaproteobacteria 15.9±1.7% and 25.8±1.4%, Actinobacteria 9.5±2.0% and 10.7±0.5%, Verrucomicrobia 8.5±1.4% and 0.6±0.2%, Planctomycetes 5.8±0.4% and 9.7±0.6%, Deltaproteobacteria 7.1±0.4% and 4.4%±0.3%, and Gammaproteobacteria 6.6±0.4% and 2.1±0.1%. The taxonomic patterns of the abundant OTUs were uniform across all the subsamples taken from each peat layer. In contrast, the taxonomic patterns of rare OTUs were different from those of the abundant OTUs and varied greatly among subsamples, in both surface and subsurface peat. In addition to the bacterial taxa listed above, rare OTUs represented the following groups: Armatimonadetes, Bacteroidetes, Chlamydia, Chloroflexi, Cyanobacteria, Elusimicrobia, Fibrobacteres, Firmicutes, Gemmatimonadetes, Spirochaetes, AD3, WS1, WS4, WS5, WYO, OD1, OP3, BRC1, TM6, TM7, WPS-2, and FCPU426. OTU richness was notably higher in the surface layer 882 OTUs than in the anoxic subsurface peat 483 OTUs, with only 96 OTUs common to both data sets. Most members of poorly studied phyla, such as the Acidobacteria, Verrucomicrobia, Planctomycetes and the candidate division TM6, showed a clear preference for growth in either oxic or anoxic conditions. Apparently, the bacterial communities in surface and subsurface layers of northern peatlands are highly diverse and taxonomically distinct, reflecting the different abiotic conditions in microhabitats within the peat profile.



Author: Yulia M. Serkebaeva , Yongkyu Kim , Werner Liesack , Svetlana N. Dedysh

Source: http://plos.srce.hr/



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