„Impuls- und Vernetzungsfonds” of the Helmholtz Association
Alfred Wegener Institute
Helmholtz Centre for Polar and Marine Research
Arctic University of Norway University of Fairbanks, Alaska
The Helmholtz Young Investigators Research Group MicroCene was established in 2013 and provides a microscope on microbial processes and distribution patterns in the terrestrial, organic rich subsurface. We apply molecular methods such as high throughput sequencing, metagenomics, bioinformatics and multivariate statistics in combination with physiological and biogeochemical methods to uncover and map microorganisms of Earth’s interior. We assess microbial constraints on near-surface greenhouse gas fluxes and extent our understanding of the critical zone. Our study sites span circumarctic peat and permafrost regions and the TERENO NE observatory (http://www.gfz-potsdam.de/wissenschaftliche-infrastruktur/regionale-observatorien/tereno/arbeitsgruppen)
We map microbial communities of the terrestrial subsurface shown here at the example of submarine permafrost. Thawing submarine permafrost is reported to be a hot spot of methane to the atmosphere. We, however, identified anaerobic methanotrophic consortia at the permafrost thaw front (https://www.nature.com/articles/s41598-018-19505-9; http://dx.doi.org/10.1002/2014JG002862) mitigating the emission of methane in this system. The top-right shows micrographs of ANME-2a consortia at the SMTZ of submarine permafrost obtained through CARD-FISH. We also found indications for proliferation of bacteria residing in the warmed permafrost (http://dx.doi.org/10.1002/2017JG003859) (https://eos.org/research-spotlights/microbes-may-thrive-in-subsea-permafrost-long-after-flooding).
The MicroCene Group (from left to right): Matthias Winkel (PostDoc), Andrea Kiss (PhD student), Anke Saborowski (Technician), Julia Mitzscherling (PhD studen), Susanne Liebner (Juniorprofessorin, Gruppenleiterin), Sizhong Yang (PostDoc), Joana MacLean (M.Sc.), Wen Xi (CSC PhD fellow)
As part of a CSC fellowship on the biogeography of methane producing archaea (Figure above) we have identified salinity as global driver of methanogenic community composition. More information can be found here: https://doi.org/10.3389/fmicb.2017.01339
The rare biosphere, the low-abundant microbial populations, is suggested to be a conserved way of microbial life. We conducted a molecular survey of rare methanogenic archaea, representing a single functional guild, in the environment targeting the mcrA gene in order to test if general concepts associated with the structure of the rare bacterial biosphere also apply to single functional groups (Figure above). Similar to what is known about rare bacterial communities, the overall contribution of rare methanogens to the alpha diversity is much larger than to Bray-Curtis measures. Moreover, a similar core group of methanogens harbored by the abundant and rare communities suggests similar sources and environmental controls of both groups. Yang et al., in press
Natural peatlands form where special environmental conditions favour the establishment of the moss family Amblystegiaceae, and the succession into Sphagnaceae peatlands (Figure below). One third of the global soil organic carbon and ten percent of the global freshwater resources are stored in peatlands. Despite their importance for the carbon and nitrogen cycling, we know very little about the ecology of peat moss associated microbial communities, and a systematic study unveiling the microbiota and its drivers in both Amblystegiaceae and Sphagnaceae peatlands is lacking. Filling this gap is part of the International Helmholtz Research Group ArcBiont .
The “Plastisphere” is a result of mankind. Plastic has a long life time and is cheap to be produced so that littering, the improper deposition of waste products at an inappropriate location, has grown into a severe problem of our society. In a pilot study as part of the master thesis of Joana MacLean we characterize terrestrial litter as a habitat of the Anthropocene. The “plastisphere” is colonized by a special biota with a reduced diversity and consisting of members of soil crusts and potential plastic degraders. The top-left picture is taken in an abandon landfill in Niemegk (Brandenburg, Germany) where life flourishes on garbage ground. The buttom left SEM picture (Foto by Sathish Mayanna, Section Interface Geochemistry) shows microbial aggregates colonizing a UV-weathered plastic chip.