Potential role of Thermus thermophilus and T. oshimai in high rates of nitrous oxide (N2O) production in ∼80 °C hot springs in the US Great Basin

Authors

Brian P. Hedlund, University of Nevada, Las VegasFollow
Austin McDonald, University of Nevada, Las VegasFollow
Jenny Lam, University of Nevada, Las VegasFollow
Jeremy A. Dodsworth, University of Nevada, Las VegasFollow
J. R. Brown
B. A. HungateFollow

Document Type

Article

Publication Date

11-2011

Publication Title

Geobiology

Volume

9

Issue

6

First page number:

471

Last page number:

480

Abstract

Ambient nitrous oxide (N₂O) emissions from Great Boiling Spring (GBS) in the US Great Basin depended on temperature, with the highest flux, 67.8 ± 2.6 μmol N₂O-N m⁻² day⁻¹, occurring in the large source pool at 82 °C. This rate of N₂O production contrasted with negligible production from nearby soils and was similar to rates from soils and sediments impacted with agricultural fertilizers. To investigate the source of N₂O, a variety of approaches were used to enrich and isolate heterotrophic micro-organisms, and isolates were screened for nitrate reduction ability. Nitrate-respiring isolates were identified by 16S rRNA gene sequencing as Thermus thermophilus (31 isolates) and T. oshimai (three isolates). All isolates reduced nitrate to N₂O but not to dinitrogen and were unable to grow with N₂O as a terminal electron acceptor. Representative T. thermophilus and T. oshimai strains contained genes with 96–98% and 93% DNA identity, respectively, to the nitrate reductase catalytic subunit gene (narG) of T. thermophilus HB8. These data implicate T. thermophilus andT. oshimai in high flux of N₂O in GBS and raise questions about the genetic basis of the incomplete denitrification pathway in these organisms and on the fate of biogenic N₂O in geothermal environments.

Keywords

Denitrification; Hot spring ecology; Hot springs; Nevada – Great Boiling Spring; Nitrates; Nitrous oxide; Thermophilic bacteria; Thermophilic microorganisms; Thermus oshimai; Thermus thermophiles

Disciplines

Bacteriology | Biochemistry | Environmental Microbiology and Microbial Ecology | Genetics and Genomics | Life Sciences | Microbiology | Terrestrial and Aquatic Ecology

Language

English

Publisher Citation

HEDLUND, B. P., MCDONALD, A. I., LAM, J., DODSWORTH, J. A., BROWN, J. R. and HUNGATE, B. A. (2011), Potential role of Thermus thermophilus and T. oshimai in high rates of nitrous oxide (N2O) production in ∼80 °C hot springs in the US Great Basin. Geobiology, 9: 471–480. doi: 10.1111/j.1472-4669.2011.00295.x

Repository Citation

Hedlund, B. P., McDonald, A., Lam, J., Dodsworth, J. A., Brown, J. R., Hungate, B. A. (2011). Potential role of Thermus thermophilus and T. oshimai in high rates of nitrous oxide (N2O) production in ∼80 °C hot springs in the US Great Basin. Geobiology, 9(6), 471-480.
http://dx.doi.org/10.1111/j.1472-4669.2011.00295.x