Methanotrophic communities in Australian woodland soils of varying salinity

Abstract

Despite their large areas and potential importance as methane sinks, the role of methane‐oxidizing bacteria (MOB) in native woodland soils is poorly understood. These environments are increasingly being altered by anthropogenic disturbances, which potentially alter ecosystem service provision. Dryland salinity is one such disturbance and is becoming increasingly prevalent in Australian soils. We used microarrays and analysis of soil physicochemical variables to investigate the methane‐oxidizing communities of several Australian natural woodland soils affected to varying degrees by dryland salinity. Soils varied in terms of salinity, gravitational water content, NO3‐N, SO4‐S and Mg, all of which explained to a significant degree MOB community composition. Analysis of the relative abundance and diversity of the MOB communities also revealed significant differences between soils of different salinities. Type II and type Ib methanotrophs dominated the soils and differences in methanotroph communities existed between salinity groups. The low salinity soils possessed less diverse MOB communities, including most conspicuously, the low numbers or absence of type II Methylocystis phylotypes. The differences in MOB communities suggest niche separation of MOB across varying salinities, as has been observed in the closely related ammonia‐oxidizing bacteria, and that anthropogenic disturbance, such as dryland salinity, has the potential to alter MOB community and therefore the methane uptake rates in soils in which disturbance occurs.

Termites Facilitate Methane Oxidation and Shape the Methanotrophic Community

“…Interestingly, type I methanotrophs represented by upland grassland soil clusters (high-indicator-value probes P_JR3.505 and P_JR3.593 [15]), Methylobacter-like and Methylococcus-like methanotrophs, and pmoA2 were indicative of the active nest material. Previously, the upland grassland soil clusters were detected in other upland soils (15,51) and thought to form the dominant population responsible for atmospheric methane oxidation in a desert soil (52). However, they were rarely detected in methane-emitting environments and are not as strictly correlated with environments which act as a sink for atmospheric methane as the USC groups (5,16,27,(53)(54)(55).…”

The Emissions of Carbon Dioxide, Methane, and Nitrous Oxide during Winter without Cultivation in Local Saline-Alkali Rice and Maize Fields in Northeast China

“…Soil samples from a depth of 0-20 cm were collected before the first gas sampling from the sampling plots, to determine the soil properties, such as pH, salinity, soil organic carbon, et al The pH, salinity, moisture (gravimetric water content), and soil organic carbon (C) were determined by the methods described by Tang et al [36]. Nitrate-N was measured by the methods described by Bissett et al [37].…”

Prerequisites for amplicon pyrosequencing of microbial methanol utilizers in the environment

“…Aerobic methylotrophs occur in terrestrial and aquatic environments on the whole planet, and have been detected in aerated and flooded soils of wetlands, grasslands, tundra, and deserts, and occur in the phyllosphere and rhizosphere of plants, in open ocean waters and other marine habitats (Giovannoni et al, 2008; Angel and Conrad, 2009; Kolb, 2009a; Wieczorek et al, 2011; Bissett et al, 2012; Gupta et al, 2012; He et al, 2012; Knief et al, 2012a; Vorholt, 2012) suggesting that their unique physiology that allows them to utilize reduced C1 compounds as carbon and energy source is of global relevance in ecosystems. Methylotrophs ubiquitously occur in terrestrial ecosystems, i.e., likely, since plants produce C1 compounds.…”