| 1. |
- Benjamin, Bolduc, et al.
(author)
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The IsoGenie database : an interdisciplinary data management solution for ecosystems biology and environmental research
- 2020
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In: PeerJ. - : PeerJ. - 2167-8359. ; 8
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Journal article (peer-reviewed)abstract
- Modern microbial and ecosystem sciences require diverse interdisciplinary teams that are often challenged in “speaking” to one another due to different languages and data product types. Here we introduce the IsoGenie Database (IsoGenieDB; https://isogenie-db.asc.ohio-state.edu/), a de novo developed data management and exploration platform, as a solution to this challenge of accurately representing and integrating heterogenous environmental and microbial data across ecosystem scales. The IsoGenieDB is a public and private data infrastructure designed to store and query data generated by the IsoGenie Project, a ~10 year DOE-funded project focused on discovering ecosystem climate feedbacks in a thawing permafrost landscape. The IsoGenieDB provides (i) a platform for IsoGenie Project members to explore the project’s interdisciplinary datasets across scales through the inherent relationships among data entities, (ii) a framework to consolidate and harmonize the datasets needed by the team’s modelers, and (iii) a public venue that leverages the same spatially explicit, disciplinarily integrated data structure to share published datasets. The IsoGenieDB is also being expanded to cover the NASA-funded Archaea to Atmosphere (A2A) project, which scales the findings of IsoGenie to a broader suite of Arctic peatlands, via the umbrella A2A Database (A2A-DB). The IsoGenieDB’s expandability and flexible architecture allow it to serve as an example ecosystems database.
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| 2. |
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| 3. |
- McCalley, Carmody, et al.
(author)
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Methane dynamics regulated by microbial community response to permafrost thaw
- 2014
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In: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 514:7523, s. 478-481
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Journal article (peer-reviewed)abstract
- Permafrost contains about 50% of the global soil carbon1. It is thought that the thawing of permafrost can lead to a loss of soil carbon in the form of methane and carbon dioxide emissions2, 3. The magnitude of the resulting positive climate feedback of such greenhouse gas emissions is still unknown3 and may to a large extent depend on the poorly understood role of microbial community composition in regulating the metabolic processes that drive such ecosystem-scale greenhouse gas fluxes. Here we show that changes in vegetation and increasing methane emissions with permafrost thaw are associated with a switch from hydrogenotrophic to partly acetoclastic methanogenesis, resulting in a large shift in the δ13C signature (10–15‰) of emitted methane. We used a natural landscape gradient of permafrost thaw in northern Sweden4, 5 as a model to investigate the role of microbial communities in regulating methane cycling, and to test whether a knowledge of community dynamics could improve predictions of carbon emissions under loss of permafrost. Abundance of the methanogen Candidatus ‘Methanoflorens stordalenmirensis’6 is a key predictor of the shifts in methane isotopes, which in turn predicts the proportions of carbon emitted as methane and as carbon dioxide, an important factor for simulating the climate feedback associated with permafrost thaw in global models3, 7. By showing that the abundance of key microbial lineages can be used to predict atmospherically relevant patterns in methane isotopes and the proportion of carbon metabolized to methane during permafrost thaw, we establish a basis for scaling changing microbial communities to ecosystem isotope dynamics. Our findings indicate that microbial ecology may be important in ecosystem-scale responses to global change.
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| 4. |
- Mondav, Rhiannon, 1972-
(author)
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An exploration of freshwater microbial ecology : from streamlined genera to global networks
- 2022
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Doctoral thesis (other academic/artistic)abstract
- Microbes are the main drivers of biogeochemical cycles on Earth and even though freshwaters cover only a small area of terrestrial surfaces their contribution to global cycles is important. Global cycles are measured by exchanges between systems e.g. water to atmosphere or lithosphere and are mediated by microbial communities. Cyanobacteria and other photosynthetic microbes can be highly abundant going through cyclic blooms. These blooms are attributed to their ability to harness sunlight and CO2 to outgrow competitors by using their complex and expensive to produce photosystems. In contrast there are microbial lineages termed ‘streamlined’, that are just as abundant as cyanobacteria at times, but who have much smaller cells, small genomes, and grow and replicate slowly. It is not immediately apparent how microbes with such different lifestyles can have similar ‘success’. By investigating individual streamlined lineages and their interactions we see that they appear to have co-evolved dependencies with each other and are highly successful as consortia. By comparing consortia from different lakes we see that streamlined microbes can sit either adjacent or in the middle of carbon cycling end-points and may be more directly involved than thought in mediating methane and CO2 ratios. An analysis of global inland water microbiomes finds that around one third of the core microbial lineages in inland waters are streamlined.
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| 5. |
- Mondav, Rhiannon, 1972-, et al.
(author)
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Biogenic methane cycling is controlled by microbial cohorts
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Other publication (other academic/artistic)abstract
- The generation and consumption of methane by aquatic microbial communities is an important contribution to the global carbon budget. We sought to broaden understanding of consortia members and interactions by combining multiple methods including analysis of natural and cultivated microbial communities. By analysing the microbial communit composition and co-occurrence patterns of a lake time-series we were able to identify potential consortia involved in methane cycling. In combination with methane flux, we also analysed the community composition and co-occurrence patterns of reduced microbial model communities with inoculum from the same lake. While the network analyses confirmed many known associations, when combined with results from mixed cultures, we noted new players in methane cycling. Cultivated model communities were shown to be an effective method to explore the rarer but still important players in methane cycling and for identifying new putative members. Here we show that using multiple methods to approach the complex problem of methane cycling consortia yields not just insights into the known taxa but highlights potential new members creating new hypotheses to be tested.
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| 6. |
- Mondav, Rhiannon, 1972-
(author)
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Development of an environmental functional gene microarray for soil microbial communities
- 2010
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In: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 76:21, s. 7161-7170
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Journal article (peer-reviewed)abstract
- Functional attributes of microbial communities are difficult to study, and most current techniques rely on DNA- and rRNA-based profiling of taxa and genes, including microarrays containing sequences of known microorganisms. To quantify gene expression in environmental samples in a culture-independent manner, we constructed an environmental functional gene microarray (E-FGA) consisting of 13,056 mRNA-enriched anonymous microbial clones from diverse microbial communities to profile microbial gene transcripts. A new normalization method using internal spot standards was devised to overcome spotting and hybridization bias, enabling direct comparisons of microarrays. To evaluate potential applications of this metatranscriptomic approach for studying microbes in environmental samples, we tested the E-FGA by profiling the microbial activity of agricultural soils with a low or high flux of N₂O. A total of 109 genes displayed expression that differed significantly between soils with low and high N₂O emissions. We conclude that mRNA-based approaches such as the one presented here may complement existing techniques for assessing functional attributes of microbial communities.
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| 7. |
- Mondav, Rhiannon, 1972-, et al.
(author)
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Discovery of a novel methanogen prevalent in thawing permafrost
- 2014
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Journal article (peer-reviewed)abstract
- Thawing permafrost promotes microbial degradation of cryo-sequestered and new carbon leading to the biogenic production of methane, creating a positive feedback to climate change. Here we determine microbial community composition along a permafrost thaw gradient in northern Sweden. Partially thawed sites were frequently dominated by a single archaeal phylotype, Candidatus ‘Methanoflorens stordalenmirensis’ gen. nov. sp. nov., belonging to the uncultivated lineage ‘Rice Cluster II’ (Candidatus ‘Methanoflorentaceae’ fam. nov.). Metagenomic sequencing led to the recovery of its near-complete genome, revealing the genes necessary for hydrogenotrophic methanogenesis. These genes are highly expressed and methane carbon isotope data are consistent with hydrogenotrophic production of methane in the partially thawed site. In addition to permafrost wetlands, ‘Methanoflorentaceae’ are widespread in high methane-flux habitats suggesting that this lineage is both prevalent and a major contributor to global methane production. In thawing permafrost, Candidatus ‘M. stordalenmirensis’ appears to be a key mediator of methane-based positive feedback to climate warming.
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| 8. |
- Mondav, Rhiannon, 1972-
(author)
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Genomic inventory of permafrost microorganisms
- 2021
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In: Microbial Life in the Cryosphere and Its Feedback on Global Change. - : Walter de Gruyter. ; , s. 43-52
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Book chapter (other academic/artistic)abstract
- The genomic inventory of a permafrost soil can be obtained through genomic charac-terization of the whole community (metagenomics) and/or an organism isolated from permafrost through culture or single-cell based methods. While there is often debate among the scientific community over whether genomic, transcriptomic, proteomic, or culture-based methods are best, the most promising current work combines knowl-edge from multiple culture-dependent and culture-independent approaches in com-parative analyses of different permafrost and active-layer soils and nearby or related ecosystems. Because high-throughput shotgun methods of genomics and proteomics are relatively recent (and not always financially accessible to research groups), most work done on permafrost communities has utilized phylogenetic surveys based on small sub-unit (SSU) rRNA and functional gene (e.g. mcrA, pmoA) surveys to charac-terize cryotic soil communities. In less than a decade, our knowledge of permafrost and cryosol communities has shifted from piece-meal to the beginnings of a holistic understanding
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| 9. |
- Mondav, Rhiannon, 1972-, et al.
(author)
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Microbial network, phylogenetic diversity and community membership in the active layer across a permafrost thaw gradient
- 2017
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In: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 19:8, s. 3201-3218
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Journal article (peer-reviewed)abstract
- Biogenic production and release of methane (CH4 ) from thawing permafrost has the potential to be a strong source of radiative forcing. We investigated changes in the active layer microbial community of three sites representative of distinct permafrost thaw stages at a palsa mire in northern Sweden. The palsa site (intact permafrost and low radiative forcing signature) had a phylogenetically clustered community dominated by Acidobacteria and Proteobacteria. The bog (thawing permafrost and low radiative forcing signature) had lower alpha diversity and midrange phylogenetic clustering, characteristic of ecosystem disturbance affecting habitat filtering. Hydrogenotrophic methanogens and Acidobacteria dominated the bog shifting from palsa-like to fen-like at the waterline. The fen (no underlying permafrost, high radiative forcing signature) had the highest alpha, beta and phylogenetic diversity, was dominated by Proteobacteria and Euryarchaeota and was significantly enriched in methanogens. The Mire microbial network was modular with module cores consisting of clusters of Acidobacteria, Euryarchaeota or Xanthomonodales. Loss of underlying permafrost with associated hydrological shifts correlated to changes in microbial composition, alpha, beta and phylogenetic diversity associated with a higher radiative forcing signature. These results support the complex role of microbial interactions in mediating carbon budget changes and climate feedback in response to climate forcing.
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| 10. |
- Mondav, Rhiannon, 1972-, et al.
(author)
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Streamlined and Abundant Bacterioplankton Thrive in Functional Cohorts
- 2020
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In: mSystems. - : American Society for Microbiology. - 2379-5077. ; 5:5
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Journal article (peer-reviewed)abstract
- While fastidious microbes can be abundant and ubiquitous in their natural communities, many fail to grow axenically in laboratories due to auxotrophies or other dependencies. To overcome auxotrophies, these microbes rely on their surrounding cohort. A cohort may consist of kin (ecotypes) or more distantly related organisms (community) with the cooperation being reciprocal or nonreciprocal and expensive (Black Queen hypothesis) or costless (by-product). These metabolic partnerships (whether at single species population or community level) enable dominance by and coexistence of these lineages in nature. Here we examine the relevance of these cooperation models to explain the abundance and ubiquity of the dominant fastidious bacterioplankton of a dimictic mesotrophic freshwater lake. Using both culture-dependent (dilution mixed cultures) and culture-independent (small subunit [SSU] rRNA gene time series and environmental metagenomics) methods, we independently identified the primary cohorts of actinobacterial genera "Candidatus Planktophila" (acI-A) and "Candidatus Nanopelagicus" (acI-B) and the proteobacterial genus "Candidatus Fonsibacter" (LD12). While "Ca Planktophila" and "Ca. Fonsibacter" had no correlation in their natural habitat, they have the potential to be complementary in laboratory settings. We also investigated the bifunctional catalase-peroxidase enzyme KatG (a common good which "Ca Planktophila" is dependent upon) and its most likely providers in the lake. Further, we found that while ecotype and community cooperation combined may explain "Ca Planktophila" population abundance, the success of "Ca. Nanopelagicus" and "Ca. Fonsibacter" is better explained as a community by-product. Ecotype differentiation of "Ca. Fonsibacter" as a means of escaping predation was supported but not for overcoming auxotrophies.IMPORTANCE This study examines evolutionary and ecological relationships of three of the most ubiquitous and abundant freshwater bacterial genera: "Ca Planktophila" (acI-A), "Ca. Nanopelagicus" (acI-B), and "Ca. Fonsibacter" (LD12). Due to high abundance, these genera might have a significant influence on nutrient cycling in freshwaters worldwide, and this study adds a layer of understanding to how seemingly competing clades of bacteria can coexist by having different cooperation strategies. Our synthesis ties together network and ecological theory with empirical evidence and lays out a framework for how the functioning of populations within complex microbial communities can be studied.
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