Microbial methane cycling in a warming world : From biosphere to atmosphere

Contains fulltext : 226903.pdf (publisher's version ) (Open Access)Summary We live in a microbial world. Microorganisms were the first life forms on our planet, shaping the Earth as we know it today. During Earth's history, a set of metabolic processes evolved exclusively in microorganisms that thrived in the absence of oxygen. One of these processes is the last step in the anaerobic degradation of organic matter: methanogenesis. This process is performed by methanogenic archaea belonging to the phylum Euryarchaeota. Although several studies indicated the potential for methanogenesis outside of this phylum, so far, no experimental evidence exists. The methane (CH4), which is the terminal product of the methanogenic pathway, contains a lot of energy and is therefore an ideal substrate for a wide range of methanotrophic organisms which constitute the biological CH4 sink. Methanotrophs occur in both the archaeal and bacterial domain, and several terminal electron acceptors can be used in the process. Anaerobic methanotrophic archaea (or ANME archaea) use the reverse methanogenesis pathway for CH4 activation and subsequent oxidation to carbon dioxide (CO2). Aerobic methanotrophic bacteria including the intra-aerobic “Candidatus Methylomirabilis sp.” species use oxygen and methane monooxygenases (MMOs) to activate CH4. The aim of this thesis was to investigate the interplay between CH4 producing and consuming organisms of the microbial CH4 cycle in a warming world. It is important to investigate climate impacts, since the balance between methanogens and methanotrophs determines the CH4 fluxes into the atmosphere. In turn, this largely determines the greenhouse gas (GHG) potential of an ecosystem, mainly due to the significantly higher climate impact of CH4, which has a 34-fold higher warming potential than CO2. To assess environmental impacts such as warming and increased nutrient availability, their effects on the microbial CH4 cycle, their interactions, and net GHG fluxes within a variety of manmade and natural methanogenic ecosystems were studied.Radboud University, 09 december 2020Promotor : Jetten, M.S.M. Co-promotor : Welte, C.U.323 p

Roles of Thermokarst Lakes in a Warming World

Contains fulltext : 222234.pdf (publisher's version ) (Open Access

Genome-based microbial ecology of anammox granules in a full-scale wastewater treatment system

Contains fulltext : 157011.pdf (publisher's version ) (Open Access)Partial-nitritation anammox (PNA) is a novel wastewater treatment procedure for energy-efficient ammonium removal. Here we use genome-resolved metagenomics to build a genome-based ecological model of the microbial community in a full-scale PNA reactor. Sludge from the bioreactor examined here is used to seed reactors in wastewater treatment plants around the world; however, the role of most of its microbial community in ammonium removal remains unknown. Our analysis yielded 23 near-complete draft genomes that together represent the majority of the microbial community. We assign these genomes to distinct anaerobic and aerobic microbial communities. In the aerobic community, nitrifying organisms and heterotrophs predominate. In the anaerobic community, widespread potential for partial denitrification suggests a nitrite loop increases treatment efficiency. Of our genomes, 19 have no previously cultivated or sequenced close relatives and six belong to bacterial phyla without any cultivated members, including the most complete Omnitrophica (formerly OP3) genome to date.10 p

Nutrient and acetate amendment leads to acetoclastic methane production and microbial community change in a non-producing australian coal well

Contains fulltext : 176750.pdf (publisher's version ) (Open Access)Coal mining is responsible for 11% of total anthropogenic methane emission thereby contributing considerably to climate change. Attempts to harvest coalbed methane for energy production are challenged by relatively low methane concentrations. In this study, we investigated whether nutrient and acetate amendment of a non-producing sub-bituminous coal well could transform the system to a methane source. We tracked cell counts, methane production, acetate concentration and geochemical parameters for 25 months in one amended and one unamended coal well in Australia. Additionally, the microbial community was analysed with 16S rRNA gene amplicon sequencing at 17 and 25 months after amendment and complemented by metagenome sequencing at 25 months. We found that cell numbers increased rapidly from 3.0 x 104 cells ml-1 to 9.9 x 107 in the first 7 months after amendment. However, acetate depletion with concomitant methane production started only after 12-19 months. The microbial community was dominated by complex organic compound degraders (Anaerolineaceae, Rhodocyclaceae and Geobacter spp.), acetoclastic methanogens (Methanothrix spp.) and fungi (Agaricomycetes). Even though the microbial community had the functional potential to convert coal to methane, we observed no indication that coal was actually converted within the time frame of the study. Our results suggest that even though nutrient and acetate amendment stimulated relevant microbial species, it is not a sustainable way to transform non-producing coal wells into bioenergy factories

The hunt for the most-wanted chemolithoautotrophic spookmicrobes

Contains fulltext : 195201.pdf (publisher's version ) (Open Access)1 juni 201817 p

Polar Fox Lagoon sediment Metagenome

Metagenomic sequencing of sediment of the Polar Fox Lagoon, Bykovsky Peninsula, Siberia, Russi

Long-term enriched methanogenic communities from thermokarst lake sediments show species-specific responses to warming

Contains fulltext : 231327.pdf (publisher's version ) (Open Access

Sequencing data: High-Level Abundances of Methanobacteriales and Syntrophobacterales May Help To Prevent Corrosion of Metal Sheet Piles

Raw metagenomics sequencing data of the paper of in 't Zandt et al. (2019) Appl Environ Microbiol 85:e01369-19. See: https://www.ncbi.nlm.nih.gov/Traces/study/?query_key=1&WebEnv=NCID_1_19997777_130.14.18.97_5555_1594043178_3696420341_0MetA0_S_HStore&o=acc_s%3Aa for sample detail