title: The Influence of Time and Plant Species on the Composition of the Decomposing Bacterial Community in a Stream Ecosystem.
abstract: Foliar chemistry influences leaf decomposition, but little is known about how litter chemistry affects the assemblage of bacterial communities during decomposition. Here we examined relationships between initial litter chemistry and the composition of the bacterial community in a stream ecosystem. We incubated replicated genotypes of Populus fremontii and P. angustifolia leaf litter that differ in percent tannin and lignin, then followed changes in bacterial community composition during 28 days of decomposition using 16S rRNA gene-based pyrosequencing. Using a nested experimental design, the majority of variation in bacterial community composition was explained by time (i.e., harvest day) (R(2) = 0.50). Plant species, nested within harvest date, explained a significant but smaller proportion of the variation (R(2) = 0.03). Significant differences in community composition between leaf species were apparent at day 14, but no significant differences existed among genotypes. Foliar chemistry correlated significantly with community composition at day 14 (r = 0.46) indicating that leaf litter with more similar phytochemistry harbor bacterial communities that are alike. Bacteroidetes and β-proteobacteria dominated the bacterial assemblage on decomposing leaves, and Verrucomicrobia and α- and δ-proteobacteria became more abundant over time. After 14 days, bacterial diversity diverged significantly between leaf litter types with fast-decomposing P. fremontii hosting greater richness than slowly decomposing P. angustifolia; however, differences were no longer present after 28 days in the stream. Leaf litter tannin, lignin, and lignin: N ratios all correlated negatively with diversity. This work shows that the bacterial community on decomposing leaves in streams changes rapidly over time, influenced by leaf species via differences in genotype-level foliar chemistry.
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA. adam.wymore@unh.edu.|Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, USA. adam.wymore@unh.edu.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Wymore
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.|Translational Genomics Research Institute, Flagstaff, AZ, USA.
authors.forename: Cindy M
authors.initials: CM
authors.lastname: Liu
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.|Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Hungate
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.|Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
authors.forename: Egbert
authors.initials: E
authors.lastname: Schwartz
authors.affiliation: Translational Genomics Research Institute, Flagstaff, AZ, USA.|School of Public Health and Health Services, George Washington University, Washington, D.C., USA.
authors.forename: Lance B
authors.initials: LB
authors.lastname: Price
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Whitham
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA.|Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA.
authors.forename: Jane C
authors.initials: JC
authors.lastname: Marks
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D008031:Lignin / Q000737:chemistry; D059013:Microbial Consortia; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry / Q000382:microbiology; D010944:Plants / Q000737:chemistry* / Q000382:microbiology*; D045483:Rivers / Q000737:chemistry* / Q000382:microbiology*; D012988:Soil Microbiology; D014197:Trees; D014589:Utah; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D008031:Lignin
keywords: 16S rRNA; Bacteria; Leaf litter chemistry; Populus; Pyrosequencing; Streams