Microbial impacts on methane emission hot spots from municipal landfills
EMSL Project ID
60417
Abstract
Landfills are responsible for 14% of methane emissions in the U.S., the third highest man-made methane emission source in the country. In Canada, landfills contribute 20% of emitted methane annually. Environment Canada identifies landfills as "the key remaining mitigation gap for methane". Cover soils experience hot spots of methane emissions associated with infrastructure puncturing the cover (e.g., methane vents, monitoring wells). These hot spots are undocumented, unmonitored methane sources which are not currently included in emissions models. Methane oxidizing microorganisms were enriched in cover soils along a 2 meter transect adjacent to hot spots at a Southern Ontario landfill, where their role in mitigating hot spot emissions is not yet understood. The specific objectives of this proposal are to (1) Determine hydro-geochemical drivers of methane oxidation in landfill cover soils and their impacts on community composition and activity; (2) Identify key methane oxidizers from landfill cover soils, including high [methane] adapted lineages with the potential to act as robust "seed" organisms in new landfill covers; and (3) Develop methods for statistically robust metaproteomic analyses with paired metagenome samples. To accomplish these objectives, we are requesting metagenome sequencing, fungal RNASeq, and metaproteomic sequencing paired with metabolite and geochemistry analyses (C, H, N, S; organic matter analyses) to characterize microbial community diversity and function at emission hot spots at three municipal landfills. We will sample cover soils from three landfills at methane emission hot spots and control locations, taking soil samples and field measurements for methane flux and soil methane concentration. Samples will be gathered along 2 m transects to assess differential community response in the same soil matrix across different methane concentrations. Soil metagenomes will clarify community diversity and will generate a databank of metagenome assembled genomes (MAGs). Fungal RNASeq will enhance binning, gene calling, and annotation for fungal representatives in the soils, who have been implicated in methane sequestration. Metaproteomic peptides will be mapped to both paired metagenomes as well as the complete databank of MAGs to identify active populations and key functions. The experimental design will allow comparison of normalization methods for peptide quantification across different underlying genomic datasets, in an effort to improve quantitative comparison between sets of paired metagenome-metaproteomes. Geochemical and metabolite data will be integrated with the multi-omic data to identify drivers of microbial methane oxidation in the different cover soils and across gradients of methane efflux levels. The work is directly in line with BER, JGI, and EMSL missions around understanding the underlying biology of organisms as they respond to their environments, across spatial scales and with a specific focus on controlling greenhouse gas emissions. The overarching goal is to identify key factors and microbial populations improving efficiency of methane oxidation under high methane flux conditions, in order to improve waste management protocols. This work may result in selection of better cover soil matrices, different standard operating protocols for landfill instrumentation installation, and/or the development of microbial "seed" cultures to be introduced to new or existing landfill covers to more effectively mitigate landfill emissions.
Project Details
Project type
FICUS Research
Start Date
2022-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator