Microbial communities across a hillslope-riparian transect shaped by proximity to the stream, groundwater table, and weathered bedrock

Adi Lavy, David Geller McGrath, Paula B. Matheus Carnevali, Jiamin Wan, Wenming Dong, Tetsu K. Tokunaga, Brian C. Thomas, Kenneth H. Williams, Susan S. Hubbard, Jillian F. Banfield

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Watersheds are important suppliers of freshwater for human societies. Within mountainous watersheds, microbial communities impact water chemistry and element fluxes as water from precipitation events discharge through soils and underlying weathered rock, yet there is limited information regarding the structure and function of these communities. Within the East River, CO watershed, we conducted a depth-resolved, hillslope to riparian zone transect study to identify factors that control how microorganisms are distributed and their functions. Metagenomic and geochemical analyses indicate that distance from the East River and proximity to groundwater and underlying weathered shale strongly impact microbial community structure and metabolic potential. Riparian zone microbial communities are compositionally distinct, from the phylum down to the species level, from all hillslope communities. Bacteria from phyla lacking isolated representatives consistently increase in abundance with increasing depth, but only in the riparian zone saturated sediments we found Candidate Phyla Radiation bacteria. Riparian zone microbial communities are functionally differentiated from hillslope communities based on their capacities for carbon and nitrogen fixation and sulfate reduction. Selenium reduction is prominent at depth in weathered shale and saturated riparian zone sediments and could impact water quality. We anticipate that the drivers of community composition and metabolic potential identified throughout the studied transect will predict patterns across the larger watershed hillslope system.

Original languageEnglish
Pages (from-to)6869-6900
Number of pages32
JournalEcology and Evolution
Volume9
Issue number12
DOIs
StatePublished - Jun 2019
Externally publishedYes

Funding

Yongman Kim—collecting samples for chemistry, and soil chemistry analysis. Wendy Brown—Information about gopher activity and vegetation at PLM sites. The work described in the manuscript was supported as part of the Watershed Function Scientific Focus Area funded by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under Award Number DE-AC02-05CH11231.

Keywords

  • metabolism
  • metagenomics
  • microbiology
  • riparian
  • soil
  • watershed

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