Evidence of Microbial Regulation of Biogeochemical Cycles from a Study on Methane Flux and Land Use Change

Abstract

h Microbes play an essential role in ecosystem functions, including carrying out biogeochemical cycles, but are currently considered a black box in predictive models and all global biodiversity debates. This is due to (i) perceived temporal and spatial variations in microbial communities and (ii) lack of ecological theory explaining how microbes regulate ecosystem functions. Providing evidence of the microbial regulation of biogeochemical cycles is key for predicting ecosystem functions, including greenhouse gas fluxes, under current and future climate scenarios. Using functional measures, stable-isotope probing, and molecular methods, we show that microbial (community diversity and function) response to land use change is stable over time. We investigated the change in net methane flux and associated microbial communities due to afforestation of bog, grassland, and moorland. Afforestation resulted in the stable and consistent enhancement in sink of atmospheric methane at all sites. This change in function was linked to a niche-specific separation of microbial communities (methanotrophs). The results suggest that ecological theories developed for macroecology may explain the microbial regulation of the methane cycle. Our findings provide support for the explicit consideration of microbial data in ecosystem/climate models to improve predictions of biogeochemical cycles.

Effects of land use conversion and fertilization on CH4 and N2O fluxes from typical hilly red soil

“…The dynamics of carbon and nitrogen in converted orchard fields significantly differed from those in paddy fields in which anaerobic decomposition process was dominant. It has been reported that CH 4 was actively produced in the anaerobic soil conditions with the preference of methanogens and emitted to the atmosphere through the rice plants (Bhattacharyya et al 2013;Nazaries et al 2013). Conversely, anaerobic conditions in the paddy plots limited nitrate availability, and anaerobiosis favored denitrification to N 2 (Zou et al 2007), thus leading to the lower N 2 O emissions.…”

Mutagenesis of the hydrocarbon monooxygenase indicates a metal centre in subunit-C, and not subunit-B, is essential for copper-containing membrane monooxygenase activity

“…CuMMOs have a central role in the microbial oxidation of a wide variety of difficult substrates including ammonia, methane, other small alkanes and chlorinated hydrocarbons (Bédard & Knowles, 1989;Conrad, 1996;Jiang et al, 2010). CuMMO-containing microbes dominate key steps in the biogeochemical cycles of methane and nitrogen, making the genes useful targets as environmental indicators (Holmes et al, 1995(Holmes et al, , 1999Menyailo et al, 2008;Nazaries et al, 2013;Op den Camp et al, 2009;Singh et al, 2010). Their activities give rise to a broad range of biotechnology applications, such as in the removal of excess nitrogen from wastewater (Abell et al, 2011;Hatzenpichler, 2012;Mußmann et al, 2011), sustainably exploiting methane for alternative fuel production (Dalton, 2005;Lieberman & Rosenzweig, 2005;Singh et al, 2010), and remediating chlorinated pollutants that persist in groundwater and soil Semrau et al, 2010).…”

Bacterial Targets as Potential Indicators of Diesel Fuel Toxicity in Subantarctic Soils

“…With developments in sequencing technologies, the phylogenetic and functional understanding of environmental microbial communities is rapidly expanding and in turn promoting the development of molecular microbial indicators as integrated measures of ecosystem health (10,11). To date, the majority of studies assessing the impact of petroleum hydrocarbons on polar soil microbial populations have focused on the stimulated portion of the bacterial community, with the aim of establishing the natural attenuation capacity of a soil or the effects of active bioremediation.…”