Wildfire impact on permafrost : changes in microbial community and soil decomposition
Permafrost is prone to thawing under disturbances resulting from frequent wildfires in boreal forests due to climate change, increasing the risk of the release of carbon (C) from it. Although the decomposition of organic C is mainly determined by the activity of soil microorganisms, productions of p...
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/318128 2023-08-20T04:09:11+02:00 Wildfire impact on permafrost : changes in microbial community and soil decomposition Zhou, Xuan Danger, Michael University of Helsinki, Faculty of Agriculture and Forestry Doctoral Programme in Interdisciplinary Environmental Sciences Helsingin yliopisto, maatalous-metsätieteellinen tiedekunta Ympäristöalan tieteidenvälinen tohtoriohjelma Helsingfors universitet, agrikultur-forstvetenskapliga fakulteten Doktorandprogrammet i tvärvetenskaplig miljöforskning Berninger, Frank Pumpanen, Jukka Heinonsalo, Jussi 2020-08-04T04:52:10Z application/pdf http://hdl.handle.net/10138/318128 eng eng Helsingin yliopisto Helsingfors universitet University of Helsinki URN:ISBN:978-951-51-6430-8 Helsinki: Hansaprint, 2020, 2342-5423 URN:ISSN:2342-5431 http://hdl.handle.net/10138/318128 URN:ISBN:978-951-51-6431-5 Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden. forest Ecology and Management Text Doctoral dissertation (article-based) Artikkeliväitöskirja Artikelavhandling doctoralThesis 2020 ftunivhelsihelda 2023-07-28T06:28:07Z Permafrost is prone to thawing under disturbances resulting from frequent wildfires in boreal forests due to climate change, increasing the risk of the release of carbon (C) from it. Although the decomposition of organic C is mainly determined by the activity of soil microorganisms, productions of pyrogenic material after fire may offset this process. To evaluate the C dynamics related to wildfire disturbance in permafrost regions, this study examined the postfire changes in soil organic matter (SOM) decomposition, and the microbial community composition and its potential functions during a > 100-year chronosequence of burnt boreal forests. Based on the kinetic theory, the temperature sensitivity of slowly decomposing SOM tends to be higher than that of easily decomposing SOM. Consistently, we found the decomposition of SOM in burnt surface soils containing less-decomposable SOM generated by fire, was more sensitive to temperature than that in old-growth forests. Fire also decreased the microbial biomass and the fungal-to-bacterial ratio of the surface soils. Despite this, soil heterotrophic respiration and the microbial C:N:P ratio in burnt forests remained similar level to that in old-growth forests regardless of the changing SOM quality and quantity. This suggests the notion of a lower microbial C use efficiency following a fire. Unexpectedly, permafrost thaw did not alter the microbial biomass and the fungal-to-bacterial ratio, but increased the microbial metabolic quotient. Illumina Miseq sequencing of bacterial 16S rDNA revealed that the bacterial community composition in recently burnt surface soils differed from it in old-growth forest soils. Permafrost thaw, however, showed little effect on the bacterial community composition. Bacterial communities of burnt surface-soil exhibited higher abundance of Ktedonobacteria (Chloroflexi) but lower abundance of Betaproteobacteria. Functional gene compositions (DNA-based) of the burnt surface soil differed from those of the unburnt ones; particularly for genes ... Doctoral or Postdoctoral Thesis permafrost Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto |
institution |
Open Polar |
collection |
Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
forest Ecology and Management |
spellingShingle |
forest Ecology and Management Zhou, Xuan Wildfire impact on permafrost : changes in microbial community and soil decomposition |
topic_facet |
forest Ecology and Management |
description |
Permafrost is prone to thawing under disturbances resulting from frequent wildfires in boreal forests due to climate change, increasing the risk of the release of carbon (C) from it. Although the decomposition of organic C is mainly determined by the activity of soil microorganisms, productions of pyrogenic material after fire may offset this process. To evaluate the C dynamics related to wildfire disturbance in permafrost regions, this study examined the postfire changes in soil organic matter (SOM) decomposition, and the microbial community composition and its potential functions during a > 100-year chronosequence of burnt boreal forests. Based on the kinetic theory, the temperature sensitivity of slowly decomposing SOM tends to be higher than that of easily decomposing SOM. Consistently, we found the decomposition of SOM in burnt surface soils containing less-decomposable SOM generated by fire, was more sensitive to temperature than that in old-growth forests. Fire also decreased the microbial biomass and the fungal-to-bacterial ratio of the surface soils. Despite this, soil heterotrophic respiration and the microbial C:N:P ratio in burnt forests remained similar level to that in old-growth forests regardless of the changing SOM quality and quantity. This suggests the notion of a lower microbial C use efficiency following a fire. Unexpectedly, permafrost thaw did not alter the microbial biomass and the fungal-to-bacterial ratio, but increased the microbial metabolic quotient. Illumina Miseq sequencing of bacterial 16S rDNA revealed that the bacterial community composition in recently burnt surface soils differed from it in old-growth forest soils. Permafrost thaw, however, showed little effect on the bacterial community composition. Bacterial communities of burnt surface-soil exhibited higher abundance of Ktedonobacteria (Chloroflexi) but lower abundance of Betaproteobacteria. Functional gene compositions (DNA-based) of the burnt surface soil differed from those of the unburnt ones; particularly for genes ... |
author2 |
Danger, Michael University of Helsinki, Faculty of Agriculture and Forestry Doctoral Programme in Interdisciplinary Environmental Sciences Helsingin yliopisto, maatalous-metsätieteellinen tiedekunta Ympäristöalan tieteidenvälinen tohtoriohjelma Helsingfors universitet, agrikultur-forstvetenskapliga fakulteten Doktorandprogrammet i tvärvetenskaplig miljöforskning Berninger, Frank Pumpanen, Jukka Heinonsalo, Jussi |
format |
Doctoral or Postdoctoral Thesis |
author |
Zhou, Xuan |
author_facet |
Zhou, Xuan |
author_sort |
Zhou, Xuan |
title |
Wildfire impact on permafrost : changes in microbial community and soil decomposition |
title_short |
Wildfire impact on permafrost : changes in microbial community and soil decomposition |
title_full |
Wildfire impact on permafrost : changes in microbial community and soil decomposition |
title_fullStr |
Wildfire impact on permafrost : changes in microbial community and soil decomposition |
title_full_unstemmed |
Wildfire impact on permafrost : changes in microbial community and soil decomposition |
title_sort |
wildfire impact on permafrost : changes in microbial community and soil decomposition |
publisher |
Helsingin yliopisto |
publishDate |
2020 |
url |
http://hdl.handle.net/10138/318128 |
genre |
permafrost |
genre_facet |
permafrost |
op_relation |
URN:ISBN:978-951-51-6430-8 Helsinki: Hansaprint, 2020, 2342-5423 URN:ISSN:2342-5431 http://hdl.handle.net/10138/318128 URN:ISBN:978-951-51-6431-5 |
op_rights |
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty. This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited. Publikationen är skyddad av upphovsrätten. Den får läsas och skrivas ut för personligt bruk. Användning i kommersiellt syfte är förbjuden. |
_version_ |
1774721974664167424 |