Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Carbon gas biogeochemistry of a northern peatland - in a dynamic permafrost landscape
Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
Responsible organisation
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is about biogeochemical processes of a northern peatland and their importance as a link between the climate and the terrestrial system. Increased temperatures on a global level, and particularly in the Arctic, have led to melting permafrost and changes in hydrology. In turn, this affect the natural exchange of radiatively important trace gases between land and atmosphere that may reinforce climate change. The aim of this thesis is to increase the understanding about the exchange of carbon dioxide (CO2), methane (CH4) and non-methane volatile organic compounds (NMVOCs) occurring in northern peatlands, to decrease uncertainty about their future carbon (C) balance. In order to pursue this aim, we designed a study that allowed measuring the C exchange at a subarctic peatland, accounting for spatial and temporal analysis at several levels.

The field site was the Stordalen mire, northern Sweden. Exchange rates of CO2, and total hydrocarbons (THCs; CH4 and NMVOCs) were measured using an automatic chamber system for up to six years, at three different types of vegetation communities and permafrost regimes. The gas exchange was found to relate to different environmental and biological variables at different vegetation communities and at different temporal scales. Differences in flux rates and controls between sites could be explained with biological and environmental variables in a better way than the seasonal and interannual variability within a site.

Snow season flux measurements were determined to be of high importance regarding the annual C budget. By excluding the snow season, the potential C source strength of a peatland is likely to be underestimated. The importance of combining the THCs with the CO2 to estimate the annual C balance was demonstrated as THC could be sufficient to shift the mire from a sink to a source of C to the atmosphere. Again, the C source strength may be significantly underestimated if only focusing on CO2 fluxes in wet peatland environments.

Place, publisher, year, edition, pages
Stockholm: Institutionen för geologi och geokemi , 2008. , 31 p.
Series
Meddelanden från Stockholms universitets institution för geologi och geokemi, ISSN 1101-1599 ; 333
Keyword [en]
Carbon balance, Carbon exchange, Peatland, Subarctic, Climate change
National Category
Earth and Related Environmental Sciences
Research subject
Geochemistry
Identifiers
URN: urn:nbn:se:su:diva-8241ISBN: 978-91-7155-743-8 (print)OAI: oai:DiVA.org:su-8241DiVA: diva2:199881
Public defence
2008-10-31, De Geersalen, Geovetenskapens hus, Svante Arrhenius väg 8 A, Stockholm, 10:00
Opponent
Supervisors
Available from: 2008-10-09 Created: 2008-10-01Bibliographically approved
List of papers
1. A Review: Fifty years of research at the subarctic Stordalen mire, northern Sweden
Open this publication in new window or tab >>A Review: Fifty years of research at the subarctic Stordalen mire, northern Sweden
Manuscript (Other academic)
Identifiers
urn:nbn:se:su:diva-25511 (URN)
Note
Part of urn:nbn:se:su:diva-8241Available from: 2008-10-09 Created: 2008-10-01 Last updated: 2010-01-13Bibliographically approved
2. Nonmethane volatile organic compound flux from a subarctic mire in northern Sweden
Open this publication in new window or tab >>Nonmethane volatile organic compound flux from a subarctic mire in northern Sweden
Show others...
2008 (English)In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 60, no 2, 226-237 p.Article in journal (Refereed) Published
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-25512 (URN)10.1111/j.1600-0889.2007.00331.x (DOI)000254277200009 ()
Note
Part of urn:nbn:se:su:diva-8241Available from: 2008-10-09 Created: 2008-10-01 Last updated: 2017-12-13Bibliographically approved
3. Total hydrocarbon flux dynamics at a subarctic mire in northern Sweden
Open this publication in new window or tab >>Total hydrocarbon flux dynamics at a subarctic mire in northern Sweden
Show others...
2008 (English)In: Journal of Geophysical Research – Biogeosciences, Vol. 113, G03026- p.Article in journal (Refereed) Published
Abstract [en]

This is a study of the spatial and temporal variability of total hydrocarbon (THC) emissions from vegetation and soil at a subarctic mire, northern Sweden. THCs include methane (CH4) and nonmethane volatile organic compounds (NMVOCs), both of which are atmospherically important trace gases and constitute a significant proportion of the carbon exchange between biosphere and atmosphere. Reliable characterization of the magnitude and the dynamics of the THC fluxes from high latitude peatlands are important when considering to what extent trace gas emissions from such ecosystems may change and feed back on climate regulation as a result of warmer climate and melting permafrost. High frequency measurements of THC and carbon dioxide (CO2) were conducted during four sequential growing seasons in three localities representing the trophic range of plant communities at the mire. The magnitude of the THC flux followed the moisture gradient with increasing emissions from a dry Palsa site (2.2 ± 0.1 mgC m−2 d−1), to a wet intermediate melt feature with Sphagnum spp. (28 ± 0.3 mgC m−2 d−1) and highest emissions from a wet Eriophorum spp. site (122 ± 1.4 mgC m−2 d−1) (overall mean ±1 SE, n = 2254, 2231 and 2137). At the Palsa site, daytime THC flux was most strongly related to air temperature while daytime THC emissions at the Sphagnum site had a stronger relation to ground temperature. THC emissions at both the wet sites were correlated to net ecosystem exchange of CO2. An overall spatial correlation indicated that areas with highly productive vegetation communities also had high THC emission potential.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-25513 (URN)10.1029/2008JG000703 (DOI)000258822700001 ()
Note
Part of urn:nbn:se:su:diva-8241Available from: 2008-10-09 Created: 2008-10-01 Last updated: 2012-03-26Bibliographically approved
4. Annual carbon gas budget for a subarctic peatland, northern Sweden
Open this publication in new window or tab >>Annual carbon gas budget for a subarctic peatland, northern Sweden
Show others...
2010 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 7, no 1, 95-108 p.Article in journal (Refereed) Published
Abstract [en]

Temperatures in the Arctic regions are rising, thawing permafrost and exposing previously stable soil organic carbon (OC) to decomposition. This can result in northern latitude soils, which have accumulated large amounts of OC potentially shifting from atmospheric C sinks to C sources with positive feedback on climate warming. In this paper, we estimate the annual net C gas balance (NCB) of the subarctic mire Stordalen, based on automatic chamber measurements of CO2 and total hydrocarbon (THC; CH4 and NMVOCs) exchange. We studied the dominant vegetation communities with different moisture and permafrost characteristics; a dry Palsa underlain by permafrost, an intermediate thaw site with Sphagnum spp. and a wet site with Eriophorum spp. where the soil thaws completely. Whole year accumulated fluxes of CO2 were estimated to 29.7, −35.3 and −34.9 gC m−2 respectively for the Palsa, Sphagnum and Eriophorum sites (positive flux indicates an addition of C to the atmospheric pool). The corresponding annual THC emissions were 0.5, 6.2 and 31.8 gC m−2 for the same sites. Therefore, the NCB for each of the sites was 30.2, −29.1 and −3.1 gC m−2 respectively for the Palsa, Sphagnum and Eriophorum site. On average, the whole mire was a CO2 sink of 2.6 gC m−2 and a THC source of 6.4 gC m−2 over a year. Consequently, the mire was a net source of C to the atmosphere by 3.9 gC m−2 (based on area weighted estimates for each of the three plant communities). Early and late snow season efflux of CO2 and THC emphasize the importance of winter measurements for complete annual C budgets. Decadal vegetation changes at Stordalen indicate that both the productivity and the THC emissions increased between 1970 and 2000. Considering the GWP100 of CH4, the net radiative forcing on climate increased 21% over the same time. In conclusion, reduced C compounds in these environments have high importance for both the annual C balance and climate.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-25514 (URN)10.5194/bg-7-95-2010 (DOI)000274058100008 ()
Available from: 2008-10-09 Created: 2008-10-01 Last updated: 2017-12-13Bibliographically approved
5. Annual cycle of methane emissions from a subarctic peatland
Open this publication in new window or tab >>Annual cycle of methane emissions from a subarctic peatland
Show others...
2010 (English)In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 115, G02009- p.Article in journal (Refereed) Published
Abstract [en]

Although much attention in recent years has been devoted to methane (CH4) emissions from northern wetlands, measurement based data sets providing full annual budgets are still limited in number. This study was designed to help fill the gap of year-round measurements of CH4 emissions from subarctic mires. We report continuous eddy correlation CH4 flux measurements made during 2006 and 2007 over the Stordalen mire in subarctic Sweden (68 degrees 20'N, 19 degrees 03'E, altitude 351 m) using a cryocooled tunable diode laser. The landscape-scale CH4 fluxes originated mainly from the permafrost free wet parts of the mire dominated by tall graminoid vegetation. The midseason average CH4 emission mean was 6.2 +/- 2.6 mg m(-2) h(-1). A detailed footprint analysis indicates an additional strong influence on the flux by the nearby shallow Lake Villasjon (0.17 km(2), maximum depth 1.3 m). A stable bimodal distribution of wind flow from either the east or the west allowed separating the lake and mire vegetation signals. The midseason lake emission rates were as high as 12.3 +/- 3.3 mg m(-2) h(-1). Documented CH4 fluxes are similar to results obtained by automatic chamber technique and higher than manual chamber measurements made in the wet minerotrophic section dominated by Eriophorum angustifolium. The high fluxes observed from this vegetation type are significant because the areal distribution of this source in the mire is expanding due to ongoing thawing of the permafrost. A simple peat temperature relationship with CH4 emissions was used to fill data gaps to construct a complete annual budget of CH4 fluxes over the studied area. The calculated annual CH4 emissions in 2006 and 2007 equaled 24.5 and 29.5 g CH4 m(-2) yr(-1), respectively. The summer season CH4 emissions dominated (65%) the annual flux, with the shoulder seasons of spring and autumn significant (25%) and a minor flux from the winter (10%).

National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-25515 (URN)10.1029/2008JG000913 (DOI)000277259700001 ()
Note
authorCount :7Available from: 2008-10-09 Created: 2008-10-01 Last updated: 2017-12-13Bibliographically approved

Open Access in DiVA

No full text

By organisation
Department of Geology and Geochemistry
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 409 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf