Biodiversity Of Bacteria And Archaea In Dajiuhu Peatland, Shennongjia

Wetlands cover approximately 3% of the land-surface and store up to 30% of the terrestrial carbon on Earth, thus play an important role in global carbon cycling and climate change. Plants residue resistant degrade as the result of anaerobic environment caused by high water table or surface flow. Accumulative intensity differs remarkably in those widespread peatland, peat re-source concentrate in middle and high latitude of northern hemisphere, such as the Russsia and the Candian, thus it was known as the boreal peatland. Rather abundance peat was estimated in the China and mainly distribute in the Yunnan-Guizhou plateau and Zoige plateau as well as the Yangze river watershed. Located in Shennongjia of middle reach of the Yangze River, Dajiuhu peatland cover the aera of about 16km2 with the elevation of 1700m. The peatland is dominated by Sphagnum and seasonal variation of water level under the monsoon climate which offer an excellent window to study the northern peatland.To investigate vertical changes of bacterial communities from living plants to the associated sediments and bacterial biogeo-chemical roles in peatland ecosystem, samples of different part of individual Sphagnum palustre and the different layers of the underlying sediments were collected from Dajiuhu Peatland in central China. All samples were subject to 16S rRNA gene clone libra-ries and quantitative PCR analysis. Even though bacteria vary in abundance at the same order of magnitude in all samples, they show great profile difference in composition from the top part of S. palustre to the low layer of the sediments. Cyanobacteria and alpha-Proteobacteria dominate at the top part whereas Acidobacteria at the middle part of S. palustre. Alpha-Proteobacteria and Acidobacteria are the dominant phyla at the bottom part of S. palustre and in the surface peat sediment. In contrast, bacterial communities in the subsurface sediments are dominated by Aci-dobacteria. These profile distributions of different bacterial communities are closely related to their ecological functions in the peatland ecosystem. Specifically, most Cyanobacteria were ob-served at the top green part of S. palustre, a horizon where the active photosynthesis of the moss occurs, which infers their endosymbiosis. In contrast, Acidobacteria dominant in the subsurface sediments, are able to decompose the specific compounds on the cell wall of Sphagnum moss and thus might play an important role in the formation of the peatland, accelrating the acidic condi-tion. Methane oxidizing process might have been underestimated in Sphagnum peatland due to the identification of Methylocystaceae in all parts of the moss investigated here. The vertical dif-ference in bacterial composition and bacterial ecological functions presented here sheds light on the understanding of biogeochemical processes, in particular the CH4 flux in peat ecosystems.Sediment and Sphagnum were re-sequenced by Miseq platform because partial information of bacterial community was presented by clone library. Numerous sequence were acquired from sediment and sphagnum and coverage reached to 98%. The number of bacterial phylum in sphagnum (19) is less articulate than those in sediment (21). Proteobacteria dominate the bacteri-al community in sphagnum, followed by Acidobacteria, Proteobacteria include α-, β-, γ-,δ-,ε-and K259 subgroup. Acidobacteria is slightly more abundant than Proteobacteia in sediment. The variation of biodiversity could be observed in different classification.137 and 195 genus were observed in sphagnum and sediment respectively. The Miseq library present entire information of microbial community compared with clone library and find numerous rare species. On the other side, the principle information has been showed by clone library such as dominant group of mi-crobial community. More cheap and saving-time of clone library that is still good research me-thod for environmental sample which occupy lower microbial biodiversity.Methanogens were not been found in Dajiuhu peatland using clone library in spite of preva-lence of methanotrophs in sphagnum and sediment. What is interesting is that only 2 clones affi-liated with TMEG next to methanosarcinetes according to phylogenetic allocation were observed. MCG5 and MCG6 belong to miscellaneous crenarchaeota group dominate archaeal group in se-diment. Besides,1.1b affiliated with Thaumarchaeota accounting for approximate 20% indicated strong ammoxidation activity. Geographical distribution pattern of archaeal communities has been elaborated by approximate 3000 archaeal 16S rRNA gene sequences in different environ-ments with wide range of physicochemical properties. Archaeal community distribution was closely correlated with temperature (Monte Carlo test. P=0.006. F=3.2) and pH (Monte Carlo test. P=0.012. F=2.3) gradient. Totally 13 indicator groups were observed in peat soil, hot spring, est-uary sediment and mangrove soil. And some of them can serve as indicators of temperature and pH condition in natural environments. Archaeal communities in peat sediment were distinct from those in other environments owing to the predominance of MCG5. MCG may be anaerobic, he-terotrophy and acid-resisting microbe. And play an important role in degradation of organic mat-ter.