Bromeliad tanks are unique habitats for microbial communities involved in methane turnover

• Published in: Plant and soil 2017-01, Vol.410 (1/2), p.167-179
• Main Authors: Brandt, Franziska B., Martinson, Guntars O., Conrad, Ralf
• Format: Article
• Language: English
• Subjects: Archaea; Biomedical and Life Sciences; Community involvement; Ecology; Environmental aspects; Flowers & plants; Habitats; Life Sciences; Methane; Microbial activity; Microbial colonies; Microorganisms; Organic matter; Oxidation; Plant Physiology; Plant Sciences; Regular Article; Slurries; Soil microorganisms; Soil Science & Conservation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-016-2988-9

Background and aims Tank bromeliads collect organic matter and rainwater (= tank slurry) between their densely arranged leaf axils for their nutrient demand. Diverse communities of microorganisms inhabit these tanks and are responsible for the breakdown of organic matter. Anaerobic degradation results in the release of substantial amounts of methane. We hypothesized that each individual bromeliad harbors its own microbial community, which is affected by chemical tank-slurry properties. We further hypothesized that methanotrophic bacteria inhabit bromeliad tank slurries, potentially able to oxidize the produced CH⁴. Methods We investigated communities of Bacteria, Archaea, methanogenic and methanotrophic microorganisms measuring their abundance (qPCR) and composition (TRFLP) within eight bromeliad tanks of the species Werauhia gladioliflora sampled in a Costa Rican lowland forest. Tank slurries were analyzed for pH, carbon, nitrogen, oxygen and fatty acid concentrations. Methane oxidation rates were determined in five bromeliad tank slurries. Results Our results showed that microbial communities differed between plants and were affected by chemical tank slurry properties. Further, not only methanogenic archaea but also methanotrophic bacteria were detected in the tanks of all bromeliad plants, the latter being potentially able to aerobically oxidize between 25 and 62 μg CH₄ gdw⁻¹ h⁻¹. Conclusion Our results indicate that every bromeliad tank is a unique island with respect to its resident microbial community. The presence of methanogens and active methanotrophs in all tank slurries further indicates the potential for both methane formation and methane oxidation.