The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses
Abstract Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documen...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2018-05-01
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| Series: | AMB Express |
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| Online Access: | http://link.springer.com/article/10.1186/s13568-018-0607-2 |
| _version_ | 1818536515992551424 |
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| author | Martine A. R. Kox Sanni L. Aalto Timo Penttilä Katharina F. Ettwig Mike S. M. Jetten Maartje A. H. J. van Kessel |
| author_facet | Martine A. R. Kox Sanni L. Aalto Timo Penttilä Katharina F. Ettwig Mike S. M. Jetten Maartje A. H. J. van Kessel |
| author_sort | Martine A. R. Kox |
| collection | DOAJ |
| description | Abstract Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mosses were incubated under either ambient or low oxygen conditions in the presence or absence of methane. Stable isotope activity assays revealed considerable nitrogen-fixing and methane-assimilating rates at all sites (1.4 ± 0.2 µmol 15N–N2 g−1 DW day−1 and 12.0 ± 1.1 µmol 13C–CH4 g−1 DW day−1, respectively). Addition of methane did not stimulate incorporation of 15N-nitrogen into biomass, whereas oxygen depletion increased the activity of the nitrogen-fixing community. Analysis of the 16S rRNA genes at the bacterial community level showed a very diverse microbiome that was dominated by Alphaproteobacteria in all sites. Bona fide methane-oxidizing taxa were not very abundant (relative abundance less than 0.1%). Based on our results we conclude that methanotrophs did not contribute significantly to nitrogen fixation in the investigated peatlands. |
| first_indexed | 2024-12-11T18:38:57Z |
| format | Article |
| id | doaj.art-7c23e3c6db6a4b09aa2c800c35456f67 |
| institution | Directory Open Access Journal |
| issn | 2191-0855 |
| language | English |
| last_indexed | 2024-12-11T18:38:57Z |
| publishDate | 2018-05-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | AMB Express |
| spelling | doaj.art-7c23e3c6db6a4b09aa2c800c35456f672022-12-22T00:54:40ZengSpringerOpenAMB Express2191-08552018-05-01811910.1186/s13568-018-0607-2The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mossesMartine A. R. Kox0Sanni L. Aalto1Timo Penttilä2Katharina F. Ettwig3Mike S. M. Jetten4Maartje A. H. J. van Kessel5Department of Microbiology, Radboud UniversityDepartment of Biological and Environmental Science, University of JyväskyläNatural Resources Institute FinlandDepartment of Microbiology, Radboud UniversityDepartment of Microbiology, Radboud UniversityDepartment of Microbiology, Radboud UniversityAbstract Biological nitrogen fixation is an important source of bioavailable nitrogen in Sphagnum dominated peatlands. Sphagnum mosses harbor a diverse microbiome including nitrogen-fixing and methane (CH4) oxidizing bacteria. The inhibitory effect of oxygen on microbial nitrogen fixation is documented for many bacteria. However, the role of nitrogen-fixing methanotrophs in nitrogen supply to Sphagnum peat mosses is not well explored. Here, we investigated the role of both oxygen and methane on nitrogen fixation in subarctic Sphagnum peat mosses. Five species of Sphagnum mosses were sampled from two mesotrophic and three oligotrophic sites within the Lakkasuo peatland in Orivesi, central Finland. Mosses were incubated under either ambient or low oxygen conditions in the presence or absence of methane. Stable isotope activity assays revealed considerable nitrogen-fixing and methane-assimilating rates at all sites (1.4 ± 0.2 µmol 15N–N2 g−1 DW day−1 and 12.0 ± 1.1 µmol 13C–CH4 g−1 DW day−1, respectively). Addition of methane did not stimulate incorporation of 15N-nitrogen into biomass, whereas oxygen depletion increased the activity of the nitrogen-fixing community. Analysis of the 16S rRNA genes at the bacterial community level showed a very diverse microbiome that was dominated by Alphaproteobacteria in all sites. Bona fide methane-oxidizing taxa were not very abundant (relative abundance less than 0.1%). Based on our results we conclude that methanotrophs did not contribute significantly to nitrogen fixation in the investigated peatlands.http://link.springer.com/article/10.1186/s13568-018-0607-2DiazotrophyMethane oxidationOxygenPeatlandSphagnum moss16S rRNA amplicon sequencing |
| spellingShingle | Martine A. R. Kox Sanni L. Aalto Timo Penttilä Katharina F. Ettwig Mike S. M. Jetten Maartje A. H. J. van Kessel The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses AMB Express Diazotrophy Methane oxidation Oxygen Peatland Sphagnum moss 16S rRNA amplicon sequencing |
| title | The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses |
| title_full | The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses |
| title_fullStr | The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses |
| title_full_unstemmed | The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses |
| title_short | The influence of oxygen and methane on nitrogen fixation in subarctic Sphagnum mosses |
| title_sort | influence of oxygen and methane on nitrogen fixation in subarctic sphagnum mosses |
| topic | Diazotrophy Methane oxidation Oxygen Peatland Sphagnum moss 16S rRNA amplicon sequencing |
| url | http://link.springer.com/article/10.1186/s13568-018-0607-2 |
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