About This Project
Methane (CH4) accounts for ~30% of climate forcing and atmospheric methane removal (AMR) has significant potential for climate mitigation. CH4 uptake by trees is a known process, but the methanotrophs responsible remain poorly understood. We have preliminary data that identified methanotrophs on tree leaves by RNAseq and measured leaf methane uptake. This project will continue this work and characterise phyllosphere methanotrophs of diverse trees to assess the potential of trees for AMR.
Ask the Scientists
Join The DiscussionMotivating Factor
CH4 emissions have contributed ~0.5 ˚C of global warming to date (IPCC, 2023). It is crucial to develop accurate CH4 flux models for natural systems that enable prediction of future CH4 dynamics. Trees are increasingly recognized as important players in the methane cycle (Covey, 2019). Estimates indicate they mediate CH4 emission (Pangala, 2017; Leung, 2024; Barba, 2024) and atmospheric CH4 uptake (Gauci, 2024a) at a scale of 10s of Mt/yr. Foliar CH4 uptake and emissions have also been reported (Gorgolewski, 2023; Karim, 2024). As such, tree CH4 fluxes should be incorporated into CH4 cycle models and are a potential lever for sink maintenance, emissions mitigation, and MR (Gauci, 2024b). To develop interventions and accurate models, we need to understand the mechanism by which CH4 is oxidized in trees. However, the mechanism behind atmospheric CH4 uptake by trees is unknown.
Specific Bottleneck
Field measurements of atmospheric CH4 uptake in upland tree stems (Gauci 2024) and leaves (Gorgolewski, 2023; Karim, 2024) suggest CH4 oxidation in bark (Leung, 2024; Putkinen, 2021) or leaves. It is assumed that specialized atmospheric methane-oxidizing bacteria (atmMOB), growing at ambient (~2 ppm) CH4 (Schmider, 2024) are responsible for tree associated CH4 uptake, but facultative MOB, supported by auxiliary substrates could also contribute to tree CH4 uptake. Experimental proof of phyllosphere uptake of atmospheric CH4 in controlled lab experiments, methanotrophy on atmospheric CH4, and identification of the responsible methanotrophs and enzyme systems is lacking. Difficulties include low uptake rates making measurements analytically challenging (Tveit, 2019), slow growth rates and low abundance of MOB. These fundamental questions need answers to evaluate the role of trees in the cycling of CH4 and for evaluating their potential role in mitigation of atmospheric CH4.
Actionable Goals
The goals of this project are to measure CH4 uptake and identify the responsible MOB in controlled experiments.
CH4 uptake will be determined for samples of foliage, bark and epiphytes from a range of tree species using a trace gas analyser capable of detection to <50ppbv CH4 in closed chambers alongside negative controls. The MOB will be characterised using a combination of targeted amplicon sequencing (pmoA, mmoX), targeted methanotroph 16S rRNA sequencing (using primers for type I and II MOB; Chen et al., 2007) and deep metagenomics. RNAseq analysis of environmental foliage samples will be used to identify MOB active in the environment and their enzyme systems.
Already established enrichments of leaf MOB will be characterised and tested for capability to uptake ambient CH4. Enrichment will be attempted with 100ppm pulses of methane and at ambient CH4.
Budget
The budget will cover personnel, metagenomic sequencing, access charges for BIFoR and consumable
Project Timeline
This project will assess rates of foliar and bark methane uptake in laboratory-controlled incubations and identify the leaf and bark-associated methanotrophs driving methane consumption.
Apr 30, 2025
Determination of CH4 uptake rates by trees and identification of the responsible methanotrophs
Meet the Team
Affiliates
Affiliates
Team Bio
In combination, our team has an extensive track record and expertise in the microbiology and ecology of trace gas degrading bacteria and methanotrophy (HS, SB & YC), trace gas measurements in diverse ecosystems and the role of trees in global methane cycling (VG), molecular microbial ecology and microbiology (SB, HS, YC, JMcD) and the investigation of tree associated microbial communities in the phyllosphere (HS & JMcD).
Hendrik Schaefer
Prof Hendrik Schäfer (HS) is an environmental microbiologist at the University of Warwick. He has expertise in analysis of microbial communities and the characterisation of trace gas degrading bacteria. Recent research has focused on identifying the molecular basis of metabolism of dimethyl sulfide (DMS) and methanethiol, microorganisms driving dimethylsulfoxide (DMSO) reduction in anoxic sediments and trace degradation in the phyllosphere of plant, showing that the tree phyllosphere is a habitat for diverse carbon monoxide (CO) degrading bacteria. He has published >50 papers (h-index: 31) ResearcherID OrcID
Sinchan Banerjee
Dr. Sinchan Banerjee (SB) is an environmental microbiologist specializing in microbial degradation of pollutants and trace gases. After completing his PhD on microaerobic BTEX degradation, he joined Schaefer’s group at Warwick in 2023 to study CO-oxidizing bacteria in the phyllosphere. Through this work, he has gained expertise in trace gas measurements, metagenomics, and isolating novel CO-oxidizing bacteria. Since 2020, he has (co)-authored 12 publications. In this project, he will be responsible for the experimental work.
Yin Chen
Prof Yin Chen is a microbiologist with a particular interest in microbial one-carbon metabolism, including methane and methylamines. In his research, he employs multidisciplinary tools ranging from molecular biology, physiology, biochemistry, structural biology, and multilayered “omics” (lipidomics, proteomics & transcriptomics) into an ecological context, particularly with respect to how microbes adapt to low nutrient conditions. He has published 125 papers (h-index 43). ResearcherID OrcidID (https://orcid.org/0000-0002-0367-4276).
James McDonald
Professor McDonald and his research team apply a combination of cultivation-based and molecular approaches to characterise and engineer both host-associated and environmental microbiomes, to understand their role in host health status, biogeochemical cycling and ecosystem function. Current research focusses on microbiome engineering approaches to address key global challenges such as waste management and sustainable fuel production (using microbiomes to produce biofuels and biogas), and in combating tree disease (engineering microbial communities for disease suppression and health promotion). Prof. McDonald is also interested in integrating knowledge on microbiome engineering and microbiome science across diverse systems (e.g. plants, humans, industrial systems) to identify key scientific principles that underpin microbiome assembly and function.
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