title: Formaldehyde as a carbon and electron shuttle between autotroph and heterotroph populations in acidic hydrothermal vents of Norris Geyser Basin, Yellowstone National Park.
abstract: The Norris Geyser Basin in Yellowstone National Park contains a large number of hydrothermal systems, which host microbial populations supported by primary productivity associated with a suite of chemolithotrophic metabolisms. We demonstrate that Metallosphaera yellowstonensis MK1, a facultative autotrophic archaeon isolated from a hyperthermal acidic hydrous ferric oxide (HFO) spring in Norris Geyser Basin, excretes formaldehyde during autotrophic growth. To determine the fate of formaldehyde in this low organic carbon environment, we incubated native microbial mat (containing M. yellowstonensis) from a HFO spring with (13)C-formaldehyde. Isotopic analysis of incubation-derived CO2 and biomass showed that formaldehyde was both oxidized and assimilated by members of the community. Autotrophy, formaldehyde oxidation, and formaldehyde assimilation displayed different sensitivities to chemical inhibitors, suggesting that distinct sub-populations in the mat selectively perform these functions. Our results demonstrate that electrons originally resulting from iron oxidation can energetically fuel autotrophic carbon fixation and associated formaldehyde excretion, and that formaldehyde is both oxidized and assimilated by different organisms within the native microbial community. Thus, formaldehyde can effectively act as a carbon and electron shuttle connecting the autotrophic, iron oxidizing members with associated heterotrophic members in the HFO community.
authors.affiliation: Chemical and Biological Signature Science Group, Pacific Northwest National Laboratory, Richland, WA, USA. james.moran@pnnl.gov.
authors.forename: James J
authors.initials: JJ
authors.lastname: Moran
authors.affiliation: Chemical and Biological Signature Science Group, Pacific Northwest National Laboratory, Richland, WA, USA.|Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS, 39529, USA.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Whitmore
authors.affiliation: Environmental and Molecular Science Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Isern
authors.affiliation: Microbiology Department, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Margaret F
authors.initials: MF
authors.lastname: Romine
authors.affiliation: Chemical and Biological Signature Science Group, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Krystin M
authors.initials: KM
authors.lastname: Riha
authors.affiliation: Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA.
authors.forename: William P
authors.initials: WP
authors.lastname: Inskeep
authors.affiliation: Chemical and Biological Signature Science Group, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Helen W
authors.initials: HW
authors.lastname: Kreuzer
mesh_terms: D000143:Acids / Q000032:analysis; D052818:Autotrophic Processes; D002244:Carbon / Q000378:metabolism; D004579:Electron Transport; D005557:Formaldehyde / Q000378:metabolism*; D052836:Heterotrophic Processes; D060086:Hydrothermal Vents / Q000737:chemistry / Q000382:microbiology*; D007501:Iron / Q000032:analysis; D010084:Oxidation-Reduction; D016942:Sulfolobales / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000143:Acids; D005557:Formaldehyde; D002244:Carbon; D007501:Iron
keywords: Acidophilic; Archaea; Carbon cycle; Carbon transfer; Yellowstone National Park