High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages
Permafrost thaw in northern peatlands often leads to increased methane (CH 4 ) emissions, but gaps remain in our understanding of the underlying controls responsible for increased emissions and the duration for which they persist. We assessed how shifting ecological conditions affect microbial commu...
Main Authors: | , , , , , |
---|---|
Format: | Text |
Language: | English |
Published: |
2022
|
Subjects: | |
Online Access: | https://doi.org/10.5194/bg-2021-337 https://bg.copernicus.org/preprints/bg-2021-337/ |
id |
ftcopernicus:oai:publications.copernicus.org:bgd100085 |
---|---|
record_format |
openpolar |
spelling |
ftcopernicus:oai:publications.copernicus.org:bgd100085 2023-05-15T17:54:53+02:00 High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages Heffernan, Liam Cavaco, Maria A. Bhatia, Maya P. Estop-Aragonés, Cristian Knorr, Klaus-Holger Olefeldt, David 2022-01-11 application/pdf https://doi.org/10.5194/bg-2021-337 https://bg.copernicus.org/preprints/bg-2021-337/ eng eng doi:10.5194/bg-2021-337 https://bg.copernicus.org/preprints/bg-2021-337/ eISSN: 1726-4189 Text 2022 ftcopernicus https://doi.org/10.5194/bg-2021-337 2022-01-17T17:22:17Z Permafrost thaw in northern peatlands often leads to increased methane (CH 4 ) emissions, but gaps remain in our understanding of the underlying controls responsible for increased emissions and the duration for which they persist. We assessed how shifting ecological conditions affect microbial communities, and the magnitude and stable isotopic signature (δ 13 C) of CH 4 emissions along a thermokarst bog transect in boreal western Canada. Thermokarst bogs develop following permafrost thaw when dry, elevated peat plateaus collapse and become saturated and dominated by Sphagnum mosses. We differentiated between a young and a mature thermokarst bog stage (~30 and years ~200 since thaw, respectively). The young bog located along the thermokarst edge, was wetter, warmer and dominated by hydrophilic vegetation compared to the mature bog. Using 16S rRNA gene high throughput sequencing, we show that microbial communities were distinct near the surface and converged with depth, but lesser differences remained down to the lowest depth (160 cm). Microbial community analysis and δ 13 C data from CH 4 surface emissions and dissolved gas depth profiles show that hydrogenotrophic methanogenesis was the dominant pathway at both sites. However, the young bog was found to have isotopically heavier δ 13 C-CH 4 in both dissolved gases profiles and surface CH 4 emissions, suggesting that acetoclastic methanogenesis was relatively more enhanced throughout the young bog peat profile. Furthermore, young bog CH 4 emissions were three times greater than the mature bog. Our study suggests that interactions between ecological conditions and methanogenic communities enhance CH 4 emissions in young thermokarst bogs, but these favorable conditions only persist for the initial decades after permafrost thaw. Text Peat permafrost Thermokarst Copernicus Publications: E-Journals Canada |
institution |
Open Polar |
collection |
Copernicus Publications: E-Journals |
op_collection_id |
ftcopernicus |
language |
English |
description |
Permafrost thaw in northern peatlands often leads to increased methane (CH 4 ) emissions, but gaps remain in our understanding of the underlying controls responsible for increased emissions and the duration for which they persist. We assessed how shifting ecological conditions affect microbial communities, and the magnitude and stable isotopic signature (δ 13 C) of CH 4 emissions along a thermokarst bog transect in boreal western Canada. Thermokarst bogs develop following permafrost thaw when dry, elevated peat plateaus collapse and become saturated and dominated by Sphagnum mosses. We differentiated between a young and a mature thermokarst bog stage (~30 and years ~200 since thaw, respectively). The young bog located along the thermokarst edge, was wetter, warmer and dominated by hydrophilic vegetation compared to the mature bog. Using 16S rRNA gene high throughput sequencing, we show that microbial communities were distinct near the surface and converged with depth, but lesser differences remained down to the lowest depth (160 cm). Microbial community analysis and δ 13 C data from CH 4 surface emissions and dissolved gas depth profiles show that hydrogenotrophic methanogenesis was the dominant pathway at both sites. However, the young bog was found to have isotopically heavier δ 13 C-CH 4 in both dissolved gases profiles and surface CH 4 emissions, suggesting that acetoclastic methanogenesis was relatively more enhanced throughout the young bog peat profile. Furthermore, young bog CH 4 emissions were three times greater than the mature bog. Our study suggests that interactions between ecological conditions and methanogenic communities enhance CH 4 emissions in young thermokarst bogs, but these favorable conditions only persist for the initial decades after permafrost thaw. |
format |
Text |
author |
Heffernan, Liam Cavaco, Maria A. Bhatia, Maya P. Estop-Aragonés, Cristian Knorr, Klaus-Holger Olefeldt, David |
spellingShingle |
Heffernan, Liam Cavaco, Maria A. Bhatia, Maya P. Estop-Aragonés, Cristian Knorr, Klaus-Holger Olefeldt, David High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
author_facet |
Heffernan, Liam Cavaco, Maria A. Bhatia, Maya P. Estop-Aragonés, Cristian Knorr, Klaus-Holger Olefeldt, David |
author_sort |
Heffernan, Liam |
title |
High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
title_short |
High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
title_full |
High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
title_fullStr |
High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
title_full_unstemmed |
High peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
title_sort |
high peatland methane emissions following permafrost thaw: enhanced acetoclastic methanogenesis during early successional stages |
publishDate |
2022 |
url |
https://doi.org/10.5194/bg-2021-337 https://bg.copernicus.org/preprints/bg-2021-337/ |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Peat permafrost Thermokarst |
genre_facet |
Peat permafrost Thermokarst |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-2021-337 https://bg.copernicus.org/preprints/bg-2021-337/ |
op_doi |
https://doi.org/10.5194/bg-2021-337 |
_version_ |
1766162750313070592 |