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- Graham, Emily B., et al.
(författare)
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Microbes as Engines of Ecosystem Function : When Does Community Structure Enhance Predictions of Ecosystem Processes?
- 2016
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Microorganisms are vital in mediating the earth's biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: 'When do we need to understand microbial community structure to accurately predict function?' We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.
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| 2. |
- Peltoniemi, Krista, et al.
(författare)
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Responses of methanogenic and methanotrophic communities to warming in varying moisture regimes of two boreal fens
- 2016
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 97, s. 144-156
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Tidskriftsartikel (refereegranskat)abstract
- Peatlands are one of the major sources of the powerful greenhouse gas methane (CH4). Our aim was to detect responses of methanogenic archaeal and methane-oxidizing bacterial (MOB) communities that control the methane (CH4) cycle to climatic warming. This study took place in two boreal fens three years after experimental warming in un-manipulated wet and drier regimes, thus simulating future climate scenarios. We determined active methanogen and MOB communities as transcripts of mcrA and pmoAgenes, along with the abundance of these genes, CH4 production and oxidation potentials, and in situ CH4 fluxes. Methanogenic community remained similar, although methanogen abundance decreased after warming. In the wet regime, this decrease resulted in a small but significant reduction on the potential CH4 production in such peat layers where the average production potential was high. Drying alone, however, reduced the potential CH4 production more than warming, and this impact was strong enough to mask the small warming impact in the drier regime. Warming did not affect the MOB community or the potential CH4 oxidation in the wet regime; however, type Ib MOB abundance decreased and MOB related to genus Methylocapsa became typical after warming in the drier regime of the southern fen. The in situ measured CH4 fluxes indicated similar patterns as potential measurements; both warming and drying reduced methane emissions, drying more than warming. These results indicate that methanogens and MOB may have different controlling patterns on CH4 fluxes when facing global warming. These patterns may further differ not only between moisture regimes, but inside the same habitat type, here boreal fen. Irrespective of this variation, the in situ CH4 fluxes still seem to respond similarly across sites.
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