Page 38 - Microbial methane cycling in a warming world From biosphere to atmosphere Michiel H in t Zandt

Chapter 1. General introduction
microbial community activity and composition over time. The methanogenic communities that showed strong responses on acetate and trimethylamine (TMA) amendment were further studied in Chapter 8. Here we used metagenomic sequencing to reconstruct metagenome- assembled genomes of the methanogenic enrichments. We found species-specific temperature responses to a long-term Arctic warming scenario, which was combined with substrate amendment to mimic the thaw-induced release of organic carbon.
Chapter 9 surveys the diversity and functional potential of the microbial communities in permafrost soils exposed to a 4°C warming scenario for over five years. The largest community shifts were observed in the transition layer and the permafrost, which are prone to warming and can be important future climate contributors in a warming world. This study revealed low GHG production in long-term warming scenarios coinciding with a decrease in the relative abundance of key metabolic pathway genes.
In Chapter 10 we used a bottom-up approach to construct a synthetic co-culture of the versatile methanogen Methanosarcina barkeri and aerobic methanotrophs under oxygen limitation. We observed tight spatial interactions between methanogens and methanotrophs, indicating the potential for close species interactions in natural ecosystems. This study provides a new method to investigate interspecies interactions of methane cycle microorganisms under an array of environmental conditions.
Finally, Chapter 11 integrates our current understanding on the effects of environmental changes on the diversity and activity of CH4 cycling microorganisms in natural and manmade ecosystems. This chapter discusses current knowledge gaps and presents directions for future research topics to increase our understanding of the microbial CH4 cycle in a warming world.
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