Consistent responses of soil microbial communities to elevated nutrient inputs in grasslands across the globe.
Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide.
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309;
Jonathan W
http://orcid.org/0000-0003-3309-2709
JW
Leff
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556;
Stuart E
SE
Jones
Commonwealth Scientific and Industrial Research Organisation Land and Water Flagship, Wembley, WA 6913, Australia;
Suzanne M
SM
Prober
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309;
Albert
A
Barberán
Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108;
Elizabeth T
ET
Borer
School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, QLD 4001, Australia;
Jennifer L
JL
Firn
Department of Physiological Diversity, Helmholtz Center for Environmental Research UFZ, 04318 Leipzig, Germany; German Centre for Integrative Biodiversity Research Halle-Jena-Leipzig, D-04103 Leipzig, Germany; Institute of Biology, Martin Luther University Halle-Wittenberg, 06108 Halle (Saale), Germany;
W Stanley
http://orcid.org/0000-0002-3404-9174
WS
Harpole
Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108;
Sarah E
SE
Hobbie
Ecology, Evolution, and Organismal Biology Department, Iowa State University, Ames, IA 50011;
Kirsten S
KS
Hofmockel
School of Biological Sciences, University of Nebraska, Lincoln, NE 68588;
Johannes M H
JM
Knops
Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546;
Rebecca L
RL
McCulley
Department of Integrative Biology, University of California, Berkeley, CA 94720;
Kimberly
K
La Pierre
Community Ecology, Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland;
Anita C
AC
Risch
Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108;
Eric W
EW
Seabloom
Community Ecology, Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, Switzerland;
Martin
M
Schütz
Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309;
Christopher
C
Steenbock
Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom.
Carly J
CJ
Stevens
Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309; Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309; noah.fierer@colorado.edu.
Noah
N
Fierer
D001105:Archaea / Q000502:physiology; D018407:Bacterial Physiological Phenomena; D017753:Ecosystem; D005658:Fungi / Q000502:physiology; D009584:Nitrogen / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D006109:Poaceae / Q000502:physiology*; D012988:Soil Microbiology
D010758:Phosphorus; D009584:Nitrogen
fertilization; shotgun metagenomics; soil bacteria; soil ecology; soil fungi