Characterization of Bacterial and Fungal Communities Reveals Novel Consortia in Tropical Oligotrophic Peatlands
Despite their importance for global biogeochemical cycles and carbon sequestration, the microbiome of tropical peatlands remains under-determined. Microbial interactions within peatlands can regulate greenhouse gas production, organic matter turnover, and nutrient cycling. Here we analyze bacterial and fungal communities along a steep P gradient in a tropical peat dome and investigate community level traits and network analyses to better understand the composition and potential interactions of microorganisms in these understudied systems and their relationship to peatland biogeochemistry. We found that both bacterial and fungal community compositions were significantly different along the P gradient, and that the low-P bog plain was characterized by distinct fungal and bacterial families. At low P, the dominant fungal families were cosmopolitan parasites and endophytes, including Clavicipitaceae (19%) in shallow soils (0–4 cm), Hypocreaceae (50%) in intermediate-depth soils (4–8 cm), and Chaetothyriaceae (45%) in deep soils (24–30 cm). In contrast, high- and intermediate-P sites were dominated by saprotrophic families at all depths. Bacterial communities were consistently dominated by the acidophilic Koribacteraceae family, with the exception of the low-P bog site, which was dominated by Acetobacteraceae (19%) and Syntrophaceae (11%). These two families, as well as Rhodospirillaceae, Syntrophobacteraceae, Syntrophorhabdaceae, Spirochaetaceae, and Methylococcaceae appeared within low-P bacterial networks, suggesting the presence of a syntrophic-methanogenic consortium in these soils. Further investigation into the active microbial communities at these sites, when paired with CH4 and CO2 gas exchange, and the quantification of metabolic intermediates will validate these potential interactions and provide insight into microbially driven biogeochemical cycling within these globally important tropical peatlands.
KeywordsMetabarcoding Microbial networks Bacterial and fungal communities Peat Phosphorus
We thank Plinio Gondola and Gabriel Jacome for coordinating sampling, and Dr. Joseph Knellmann for guidance on estimation of rrn operon copy numbers.
This research was supported by grants from the National Science Foundation (DEB 0841596), the UF Informatics Institute, the Smithsonian Tropical Research Institute, and the UF Tropical Conservation and Development Program.
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflicts of interest.
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