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Complex organic matter breakdown and carbon cycling in wetlands

Methane is a major driver of global climate change and it is a product of anaerobic organic matter breakdown. A significant proportion of anthropogenic methane is emitted from (artificial) wetlands, including rice paddies. Microbes in wetlands are commonly exposed to recalcitrant organic carbon in form of complex polysaccharides and lignins. Methane emissions from wetlands are rate-limited by the breakdown of these carbon sources (Figure 7). The enzymatic toolkit needed for breaking down these carbon sources and the microbes possessing them are highly diverse.

Considering the ongoing advance of global climate change, methane emissions from wetlands are expected to increase as so far buried organic carbon becomes more prone to breakdown. The only known sink of atmospheric methane and C1 compounds contributing to methane emissions are methanotrophic/methylotrophic prokaryotes, which makes them a prime target to learn more about natural mechanisms of methane mitigation.

Motivation

Past and ongoing research of mine is driven by the goal of learning more about complex carbon turnover in artificial and natural wetlands. A more recent aspect of this research is the effect of environmental stress (salt stress, draught) on complex organic carbon turnover. Moreover, I'm interested in methylotrophs/methanotrophs from environments exposed to naturally high methane concentrations (e.g. the surrounding of methane seeps, Figure 8), and extreme environments in general to learn more about underlying mechanisms of C1 carbon turnover.

Wu X, Liu P, Wegner CE, Luo Y, Xiao K-Q, Cui Z, Zhang F, Liesack W, Peng J (2021) Deciphering microbial mechanism underlying soil organic carbon storage in a wheat maize rotation system. Sci. Total Environ. 788:147798 10.1016/j.scitotenv.2021.147798

Abdallah RZ, Wegner CE, Liesack W (2019) Community transcriptomics reveals drainage effects on paddy soil microbiome across all three domains of life. Soil Biol. Biochem. 132:131-142 10.1016/j.soilbio.2019.01.023

Peng J, Wegner CE, Bei Q, Liu P, Liesack W (2018) Metatranscriptomics reveals a different temperature effect on the structural and functional organization of the anaerobic food web in rice field soil. Microbiome 6:169 10.1186/s40168-018-0546-9

Peng J, Wegner CE, Liesack W (2017) Short-term exposure of paddy soil microbial communities to salt stress triggers different transcriptional responses of key taxonomic groups. Front. Microbiol. 8:400 10.3389/fmicb.2017.00400

Ivanova AA, Wegner CE, Kim Y, Liesack W, Dedysh SN (2016) Identification of microbial populations driving biopolymer degradation in acidic peatlands by metatranscriptomic analysis. Mol. Ecol. 19:4818-4835 10.1111/mec.13806

Wegner CE, Liesack W (2016) Microbial community dynamics during the early stages of plant polymer breakdown in paddy soil. Environ. Microbiol. 18: 2825-2842 10.1111/1462-2920.12815

Oshkin IY, Wegner CE, Lüke C, Glagolev MV, Filippov IV, Pimenov NV, Liesack W, Dedysh SN (2014) Gammaproteobacterial methanotrophs dominate cold methane seeps in floodplains of Western Siberian Rivers. Appl. Environ. Microbiol. 80: 5944-5954 10.1128/AEM.01539-14