Constraints on potential enzyme activities in thermokarst bogs : Implications for the carbon balance of peatlands following thaw
© 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd.
| Publié dans: | Global change biology. - 1999. - 27(2021), 19 vom: 06. Okt., Seite 4711-4726 |
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| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2021
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| Accès à la collection: | Global change biology |
| Sujets: | Journal Article organic matter quality peat pore water peatland permafrost soil enzyme activities soil organic carbon thermokarst Greenhouse Gases Soil plus... |
| Résumé: | © 2021 The Authors. Global Change Biology published by John Wiley & Sons Ltd. Northern peatlands store a globally significant amount of soil organic carbon, much of it found in rapidly thawing permafrost. Permafrost thaw in peatlands often leads to the development and expansion of thermokarst bogs, where microbial activity will determine the stability of the carbon storage and the release of greenhouse gases. In this study, we compared potential enzyme activities between young (thawed ~30 years ago) and mature (~200 years) thermokarst bogs, for both shallow and deep peat layers. We found very low potential enzyme activities in deep peat layers, with no differences between the young and mature bogs. Peat quality at depth was found to be highly humified (FTIR analysis) in both the young and mature bogs. This suggests that deep, old peat was largely stable following permafrost thaw, without a rapid pulse of decomposition during the young bog stage. For near-surface peat, we found significantly higher potential enzyme activities in the young bog than in the mature-associated with differences in peat quality derived from different Sphagnum species. A laboratory incubation of near-surface peat showed that differences in potential enzyme activity were primarily influenced by peat type rather than oxygen availability. This suggested that the young bog can have higher rates of near-surface decomposition despite being substantially wetter than the mature bog. Overall, our study shows that peat properties are the dominant constraint on potential enzyme activity and that peatland site development (successional pathways and permafrost history) through its influence on peat type and chemistry is likely to determine peat decomposition following permafrost thaw |
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| Description: | Date Completed 20.09.2021 Date Revised 20.09.2021 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1365-2486 |
| DOI: | 10.1111/gcb.15758 |