Bentho-pelagischer Transport methanotropher Mikroorganismen über Gasblasen
Zusammenfassung der Projektergebnisse
Pelagic methane (CH4) oxidation is the final sink for seabed-derived CH4 before its release into the atmosphere. Especially at cold vents, where large amounts of CH4 bypass the sedimentary microbial CH4 sinks, the role of pelagic CH4 oxidation in reducing the CH4 emission from the ocean becomes even more important. Pelagic CH4 turnover at highly active seeps is controlled by environmental factors such as CH4 availability, differential circulation patterns, and redox conditions. Our new results obtained at the Blowout (North Sea) demonstrate that, apart from these factors, the dislocation of benthic methanotrophs into the water column can spontaneously boost the CH4 oxidation capacity within the dispersing CH4 plume. This transport mechanism becomes even more critical at seep sites characterized by water residence times that are too short to allow the relatively slow-growing methanotrophic community to establish a resilient CH4 sink. Furthermore, in our detailed mechanist studies at the Coal Oil Point seep field (COP, California), it was found that the bubble-mediated transport efficiency was dependent on the volumetric gas flow, with the highest transport rate of MOB cells at a relatively low volumetric gas flow, and the lowest rate at a high gas flow. The bubble-mediated link between the benthic and pelagic environment was further supported by genetic analyses, indicating a transportation of methanotrophs of the family Methylomonaceae and oil degrading bacteria of the genus Cycloclasticus from the sediment into the water column. In addition, our incubation experiments showed that MOB transported from the sediment into the water column can survive over a time span of days and weeks, indicated by constant CH4 oxidation and a growth of the MOB community. In summary, our new findings demonstrate that the bubble-mediated transport of microorganisms influences the pelagic microbial abundance and community composition at gasreleasing seep sites, and increases the CH4 oxidation capacity in the dispersing plume water.
Projektbezogene Publikationen (Auswahl)
- (2020). Bubble-mediated transport of benthic microorganisms into the water column: Identification of methanotrophs and implication of seepage intensity on transport efficiency. Scientific Reports. 10: 4682
Jordan, S. F. A., T. Treude, I. Leifer, R. Janßen, J. Werner, H. Schulz-Vogt and O. Schmale
(Siehe online unter https://doi.org/10.1038/s41598-020-61446-9)
