title: Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?
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.
authors.affiliation: Institute of Arctic and Alpine Research, University of Colorado Boulder, BoulderCO, USA; Biological Sciences Division, Pacific Northwest National Laboratory, RichlandWA, USA.
authors.forename: Emily B
authors.initials: EB
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authors.affiliation: Institute of Arctic and Alpine Research, University of Colorado Boulder, BoulderCO, USA; US Department of Energy, Joint Genome Institute, Walnut CreekCA, USA.
authors.forename: Joseph E
authors.initials: JE
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authors.affiliation: Department of Forest Ecology, Federal Research and Training Centre for Forests, Bundesforschungs- und Ausbildungszentrum für Wald Vienna, Austria.
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authors.lastname: Schindlbacher
authors.affiliation: Department of Soil Science, University of Saskatchewan, Saskatoon SK, Canada.
authors.forename: Steven
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authors.affiliation: Helmholtz Centre for Environmental Research - Centre for Environmental Biotechnology Leipzig, Germany.
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authors.affiliation: Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign, Urbana IL, USA.
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authors.affiliation: Institut National de la Recherche Agronomique - Agroecology Dijon, France.
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authors.affiliation: Institute of Biological and Environmental Sciences, University of Aberdeen Aberdeen, UK.
authors.forename: James
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authors.forename: Arnaud
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authors.lastname: Yuste
authors.affiliation: Environment Centre Wales, Bangor University Gwynedd, UK.
authors.forename: Helen C
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authors.lastname: Glanville
authors.affiliation: Environment Centre Wales, Bangor University Gwynedd, UK.
authors.forename: Davey L
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authors.lastname: Jones
authors.affiliation: Department of Microbiology and Ecosystem Science, University of Vienna Vienna, Austria.
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authors.affiliation: Häme University of Applied Sciences Hämeenlinna, Finland.
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authors.forename: Lachlan J
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authors.affiliation: Institute of Landscape Ecology, University of Münster Münster, Germany.
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authors.forename: Henri M P
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authors.affiliation: Institute of Soil Science and Site Ecology, Technische University Dresden, Germany.
authors.forename: Karin
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authors.affiliation: Institute of Aquatic Ecology, Facultat de Ciències, University of Girona Girona, Spain.
authors.forename: Lluís
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authors.affiliation: Institute for Sustainability Sciences - Agroscope Zurich, Switzerland.
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authors.forename: Samiran
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authors.forename: Ri-Qing
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authors.forename: Geraldine
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authors.affiliation: Department of Microbiology and Ecosystem Science, University of Vienna Vienna, Austria.
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authors.affiliation: Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna Vienna, Austria.
authors.forename: Marianne
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authors.affiliation: Department of Ecosystem and Conservation Sciences, University of Montana, Missoula MT, USA.
authors.forename: Sarah C
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authors.affiliation: Department of Biological Science, Virginia Institute of Marine Science, Gloucester Point VA, USA.
authors.forename: Bongkeun
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authors.forename: Amitava
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authors.affiliation: LEPABE - Laboratory for Process Engineering, Environmental, Biotechnology and Energy, Faculdade de Engenharia da Universidade do Porto Porto, Portugal.
authors.forename: Olga C
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authors.affiliation: LEPABE - Laboratory for Process Engineering, Environmental, Biotechnology and Energy, Faculdade de Engenharia da Universidade do Porto Porto, Portugal.
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authors.forename: Aurore
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authors.forename: Jordi
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authors.affiliation: Centre de Recerca Ecològica i Aplicacions Forestals, Cerdanyola del Vallès Barcelona, Spain.
authors.forename: Josep
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authors.affiliation: School of Civil and Environmental Engineering, Yonsei University Seoul, South Korea.
authors.forename: Hojeong
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authors.affiliation: Department of Applied Biological Chemistry, The University of Tokyo Tokyo, Japan.
authors.forename: Kazuo
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authors.affiliation: Department of Biomedicine, Biotechnology and Public Health, University of Cadiz Puerto Real, Spain.
authors.forename: Sokratis
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authors.affiliation: Research Centre for Agrobiology and Pedology Florence, Italy.
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authors.affiliation: Research Centre for Agrobiology and Pedology Florence, Italy.
authors.forename: Alessandra
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authors.affiliation: Department of Ecology and Genetics/Limnology, Uppsala University Uppsala, Sweden.
authors.forename: Eva S
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authors.affiliation: Vale Living with Lakes Centre and Department of Biology, Laurentian University, Sudbury ON, Canada.
authors.forename: Nathan
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authors.affiliation: Institute of Arctic and Alpine Research, University of Colorado Boulder, BoulderCO, USA; Biology Department, Duke University, DurhamNC, USA.
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keywords: denitrification; ecosystem processes; functional gene; microbial diversity; microbial ecology; nitrification; respiration; statistical modeling