Environmental predictors of electroactive bacterioplankton in small boreal lakes

Charles N. Olmsted, Roger Ort, Patricia Q. Tran, Elizabeth A. McDaniel, Eric E. Roden, Daniel R. Bond, Shaomei He, Katherine D. McMahon

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Extracellular electron transfer (EET) by electroactive bacteria in anoxic soils and sediments is an intensively researched subject, but EET's function in planktonic ecology has been less considered. Following the discovery of an unexpectedly high prevalence of EET genes in a bog lake's bacterioplankton, we hypothesized that the redox capacities of dissolved organic matter (DOM) enrich for electroactive bacteria by mediating redox chemistry. We developed the bioinformatics pipeline FEET (Find EET) to identify and summarize predicted EET protein-encoding genes from metagenomics data. We then applied FEET to 36 bog and thermokarst lakes and correlated gene occurrence with environmental data to test our predictions. Our results provide indirect evidence that DOM may participate in bacterioplankton EET. We found a similarly high prevalence of genes encoding putative EET proteins in most of these lakes, where oxidative EET strongly correlated with DOM. Numerous novel clusters of multiheme cytochromes that may enable EET were identified. Taxa previously not considered EET-capable were found to carry EET genes. We propose that EET and DOM interactions are of ecologically important to bacterioplankton in small boreal lakes, and that EET, particularly by methylotrophs and anoxygenic phototrophs, should be further studied and incorporated into methane emission models of melting permafrost.

Original languageEnglish (US)
Pages (from-to)705-720
Number of pages16
JournalEnvironmental microbiology
Volume25
Issue number3
DOIs
StatePublished - Mar 2023

Bibliographical note

Funding Information:
We give special thanks to Moritz Buck, Sarahi L. Garcia, Leyden Fernandez, Gaëtan Martin, Gustavo A. Martinez‐Rodriguez, Jatta Saarenheimo, Jakob Zopfi, Stefan Bertilsson, and Sari Peura for early access to and setup with their data set (Buck et al., 2021 ) to support this ‘pandemic project’. We thank the University of Wisconsin (UW)‐Trout Lake Station, the UW Center for Limnology, and the John and Patricia Lane Award program for their invaluable support. We thank the U.S. National Science Foundation North Temperate Lakes Long‐Term Ecological Research site (NTL‐LTER DEB‐1440297; DEB‐0702395) for providing funding of the Microbial Observatory for long‐term sampling of Lake Mendota and Trout Bog. We thank the U.S. Department of Energy Joint Genome Institute for sequencing and assembly (CSPs 394 and 2796). This research was also performed in part using the Wisconsin Energy Institute computing cluster, which is supported by the Great Lakes Bioenergy Research Center as part of the U.S. Department of Energy Office of Science. We are also thankful for fellowships provided through the Department of Bacteriology at UW‐Madison.

Funding Information:
We give special thanks to Moritz Buck, Sarahi L. Garcia, Leyden Fernandez, Gaëtan Martin, Gustavo A. Martinez-Rodriguez, Jatta Saarenheimo, Jakob Zopfi, Stefan Bertilsson, and Sari Peura for early access to and setup with their data set (Buck et al., 2021) to support this ‘pandemic project’. We thank the University of Wisconsin (UW)-Trout Lake Station, the UW Center for Limnology, and the John and Patricia Lane Award program for their invaluable support. We thank the U.S. National Science Foundation North Temperate Lakes Long-Term Ecological Research site (NTL-LTER DEB-1440297; DEB-0702395) for providing funding of the Microbial Observatory for long-term sampling of Lake Mendota and Trout Bog. We thank the U.S. Department of Energy Joint Genome Institute for sequencing and assembly (CSPs 394 and 2796). This research was also performed in part using the Wisconsin Energy Institute computing cluster, which is supported by the Great Lakes Bioenergy Research Center as part of the U.S. Department of Energy Office of Science. We are also thankful for fellowships provided through the Department of Bacteriology at UW-Madison.

Funding Information:
National Science Foundation North Temperate Lakes Long‐Term Ecological Research, Grant/Award Number: NTL‐LTER DEB‐1440297; DEB‐0702395 Funding information

Publisher Copyright:
© 2022 The Authors. Environmental Microbiology published by Applied Microbiology International and John Wiley & Sons Ltd.

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