Termites Facilitate Methane Oxidation and Shape the Methanotrophic Community

Abstract

g Termite-derived methane contributes 3 to 4% to the total methane budget globally. Termites are not known to harbor methaneoxidizing microorganisms (methanotrophs). However, a considerable fraction of the methane produced can be consumed by methanotrophs that inhabit the mound material, yet the methanotroph ecology in these environments is virtually unknown. The potential for methane oxidation was determined using slurry incubations under conditions with high (12%) and in situ (ϳ0.004%) methane concentrations through a vertical profile of a termite (Macrotermes falciger) mound and a reference soil. Interestingly, the mound material showed higher methanotrophic activity. The methanotroph community structure was determined by means of a pmoA-based diagnostic microarray. Although the methanotrophs in the mound were derived from populations in the reference soil, it appears that termite activity selected for a distinct community. Applying an indicator species analysis revealed that putative atmospheric methane oxidizers (high-indicator-value probes specific for the JR3 cluster) were indicative of the active nest area, whereas methanotrophs belonging to both type I and type II were indicative of the reference soil. We conclude that termites modify their environment, resulting in higher methane oxidation and selecting and/or enriching for a distinct methanotroph population.

Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio‐based residue application

“…PCR amplification to detect the Methylocella-specific mmoX gene (encoding for the soluble methane monooxygenase) was performed using the mmoXLF/mmoXLR primer combination according to (Rahman et al, 2011) with minor modifications (Ho et al, 2013a).…”

“…Similarly, other well-aerated native (e.g. forest soils) and agricultural soils have shown the capacity to oxidize methane over a wide concentration range (Menyailo et al, 2008;Shrestha et al, 2012;Ho et al, 2013a), which may reflect seasonal fluctuations in methane concentrations (Horz et al, 2002), and indicate the occurrence of methanogenesis. Hence, methanotrophs in our agricultural soils may benefit after a rain event when methane production is stimulated.…”

Economic and ecological importance of termites: A global review

“…Termite‐derived methane contributes from 3% to 4% of the total methane budget globally (Ho et al . ). According to the recent estimates of De Gerenyu et al .…”

“…Emission from termites ranges from 1.0 mg CH 4 kg/termite/h in deserts to 8.0 mg CH 4 kg/termite/h in savannas (Ito & Inatomi 2012). Termite-derived methane contributes from 3% to 4% of the total methane budget globally (Ho et al 2013). According to the recent estimates of De Gerenyu et al (2015), CO 2 emissions from termite mounds account for up to 10% of the total CO 2 emissions in a tropical forest in south Vietnam (Ohashi et al 2017).…”

Termite mounds contain distinct methanotroph communities that are kinetically adapted to elevated methane concentrations

“…However, many termite colonies construct large mounds built from soil material or build their nest in soil, which is generally a sink for atmospheric CH 4 [11]. While results from incubation experiments of mound material were conflicting [12–14], we recently presented clear evidence of widespread CH 4 oxidation in North Australian termite mounds [7]: results from three different in situ methods to measure CH 4 oxidation in mounds confirmed that methanotrophs mitigate between 20 to 80 % of termite-derived CH 4 before emission to the atmosphere. However, the community composition and kinetic behaviour of the methanotrophs responsible remain largely unknown.…”