Global Biogeographic Analysis of Methanogenic Archaea Identifies Community-Shaping Environmental Factors of Natural Environments

Abstract

Methanogenic archaea are important for the global greenhouse gas budget since they produce methane under anoxic conditions in numerous natural environments such as oceans, estuaries, soils, and lakes. Whether and how environmental change will propagate into methanogenic assemblages of natural environments remains largely unknown owing to a poor understanding of global distribution patterns and environmental drivers of this specific group of microorganisms. In this study, we performed a meta-analysis targeting the biogeographic patterns and environmental controls of methanogenic communities using 94 public mcrA gene datasets. We show a global pattern of methanogenic archaea that is more associated with habitat filtering than with geographical dispersal. We identify salinity as the control on methanogenic community composition at global scale whereas pH and temperature are the major controls in non-saline soils and lakes. The importance of salinity for structuring methanogenic community composition is also reflected in the biogeography of methanogenic lineages and the physiological properties of methanogenic isolates. Linking methanogenic alpha-diversity with reported values of methane emission identifies estuaries as the most diverse methanogenic habitats with, however, minor contribution to the global methane budget. With salinity, temperature and pH our study identifies environmental drivers of methanogenic community composition facing drastic changes in many natural environments at the moment. However, consequences of this for the production of methane remain elusive owing to a lack of studies that combine methane production rate with community analysis.

Impact of Peat Mining and Restoration on Methane Turnover Potential and Methane-Cycling Microorganisms in a Northern Bog

“…Consistent with previous studies, we detected a predominance of Methanoregula, a genus represented by hydrogenotrophic methanogens which showed a preference for acidic conditions, in the natural and restored peatlands (11,(17)(18)(19). Methanoregula-like methanogens decreased with mining and abandonment, while the relative abundances of Methanosaeta-like and Methanosarcina-like methanogens increased.…”

“…and likely favor the proliferation of some methanogens and methanotrophs (13). For instance, methane is primarily produced by hydrogenotrophic methanogenic archaea rather than aceticlastic ones in ombrotrophic peatlands (14)(15)(16)(17)(18). These include members of the genera Methanoregulaceae and "Candidatus Methanoflorentaceae," which are predominant, and, to a lesser extent, Methanosarcinaceae (17,19).…”

PhyMet2: a database and toolkit for phylogenetic and metabolic analyses of methanogens

“…The data contained in PhyMet 2 was used to develop a web server, MethanoGram, that quickly and accurately predicts conditions for optimal growth of methanogens: temperature, pH and NaCl concentration, that is, the key factors that shape the composition of methanogenic communities (Wen et al, 2017). Using this tool, researchers could reduce the number of experiments and thus the cost of searching for the optimal culturing conditions of newly discovered methanogens.…”

Methane distribution and oxidation around the Lena Delta in summer 2013

“…A previous molecular approach identified salinity, temperature, and pH as the most important environmental drivers of methanogenic community composition on a global scale (Wen et al, 2017). However, the mechanisms by which changes in these factors influence the methanogenesis rate remain elusive, due to the lack of studies that combine methane production rates with community analyses (Wen et al, 2017).…”