CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone
In spite of advances in greenhouse gas research, the spatiotemporal CH<sub>4</sub> and N<sub>2</sub>O dynamics of boreal landscapes remain challenging, e.g., we need clarification of whether forest–mire transitions are occasional hotspots of landscape CH<sub>4</sub&g...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-01-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/281/2015/bg-12-281-2015.pdf |
| _version_ | 1811311869072244736 |
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| author | B. Tupek K. Minkkinen J. Pumpanen T. Vesala E. Nikinmaa |
| author_facet | B. Tupek K. Minkkinen J. Pumpanen T. Vesala E. Nikinmaa |
| author_sort | B. Tupek |
| collection | DOAJ |
| description | In spite of advances in greenhouse gas research, the spatiotemporal
CH<sub>4</sub> and N<sub>2</sub>O dynamics of boreal landscapes remain challenging, e.g.,
we need clarification of whether forest–mire transitions are occasional
hotspots of landscape CH<sub>4</sub> and N<sub>2</sub>O emissions during exceptionally
high and low ground water level events.
<br><br>
In our study, we tested the differences and drivers of CH<sub>4</sub> and N<sub>2</sub>O
dynamics of forest/mire types in field conditions along the soil moisture
gradient of the forest–mire ecotone. Soils changed from Podzols to Histosols
and ground water rose downslope from a depth of 10 m in upland sites to
0.1 m in mires. Yearly meteorological conditions changed from being
exceptionally wet to typical and exceptionally dry for the local climate. The
median fluxes measured with a static chamber technique varied from −51 to
586 μg m<sup>−2</sup> h<sup>−1</sup> for CH<sub>4</sub> and from 0 to
6 μg m<sup>−2</sup> h<sup>−1</sup> for N<sub>2</sub>O between forest and mire types
throughout the entire wet–dry period.
<br><br>
In spite of the highly dynamic soil water fluctuations in carbon rich soils
in forest–mire transitions, there were no large peak emissions in CH<sub>4</sub>
and N<sub>2</sub>O fluxes and the flux rates changed minimally between years.
Methane uptake was significantly lower in poorly drained transitions than in
the well-drained uplands. Water-saturated mires showed large CH<sub>4</sub>
emissions, which were reduced entirely during the exceptional summer drought
period. Near-zero N<sub>2</sub>O fluxes did not differ significantly between the
forest and mire types probably due to their low nitrification potential. When
upscaling boreal landscapes, pristine forest–mire transitions should be
regarded as CH<sub>4</sub> sinks and minor N<sub>2</sub>O sources instead of CH<sub>4</sub> and
N<sub>2</sub>O emission hotspots. |
| first_indexed | 2024-04-13T10:26:30Z |
| format | Article |
| id | doaj.art-af1c6cbc998449b3b0dac763edbe0899 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-04-13T10:26:30Z |
| publishDate | 2015-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-af1c6cbc998449b3b0dac763edbe08992022-12-22T02:50:18ZengCopernicus PublicationsBiogeosciences1726-41701726-41892015-01-0112228129710.5194/bg-12-281-2015CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotoneB. Tupek0K. Minkkinen1J. Pumpanen2T. Vesala3E. Nikinmaa4Department of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, FinlandDepartment of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, FinlandDepartment of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, FinlandDepartment of Physics, P.O. Box 48, 00014 University of Helsinki, FinlandDepartment of Forest Sciences, P.O. Box 27, 00014 University of Helsinki, FinlandIn spite of advances in greenhouse gas research, the spatiotemporal CH<sub>4</sub> and N<sub>2</sub>O dynamics of boreal landscapes remain challenging, e.g., we need clarification of whether forest–mire transitions are occasional hotspots of landscape CH<sub>4</sub> and N<sub>2</sub>O emissions during exceptionally high and low ground water level events. <br><br> In our study, we tested the differences and drivers of CH<sub>4</sub> and N<sub>2</sub>O dynamics of forest/mire types in field conditions along the soil moisture gradient of the forest–mire ecotone. Soils changed from Podzols to Histosols and ground water rose downslope from a depth of 10 m in upland sites to 0.1 m in mires. Yearly meteorological conditions changed from being exceptionally wet to typical and exceptionally dry for the local climate. The median fluxes measured with a static chamber technique varied from −51 to 586 μg m<sup>−2</sup> h<sup>−1</sup> for CH<sub>4</sub> and from 0 to 6 μg m<sup>−2</sup> h<sup>−1</sup> for N<sub>2</sub>O between forest and mire types throughout the entire wet–dry period. <br><br> In spite of the highly dynamic soil water fluctuations in carbon rich soils in forest–mire transitions, there were no large peak emissions in CH<sub>4</sub> and N<sub>2</sub>O fluxes and the flux rates changed minimally between years. Methane uptake was significantly lower in poorly drained transitions than in the well-drained uplands. Water-saturated mires showed large CH<sub>4</sub> emissions, which were reduced entirely during the exceptional summer drought period. Near-zero N<sub>2</sub>O fluxes did not differ significantly between the forest and mire types probably due to their low nitrification potential. When upscaling boreal landscapes, pristine forest–mire transitions should be regarded as CH<sub>4</sub> sinks and minor N<sub>2</sub>O sources instead of CH<sub>4</sub> and N<sub>2</sub>O emission hotspots.http://www.biogeosciences.net/12/281/2015/bg-12-281-2015.pdf |
| spellingShingle | B. Tupek K. Minkkinen J. Pumpanen T. Vesala E. Nikinmaa CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone Biogeosciences |
| title | CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone |
| title_full | CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone |
| title_fullStr | CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone |
| title_full_unstemmed | CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone |
| title_short | CH<sub>4</sub> and N<sub>2</sub>O dynamics in the boreal forest–mire ecotone |
| title_sort | ch sub 4 sub and n sub 2 sub o dynamics in the boreal forest mire ecotone |
| url | http://www.biogeosciences.net/12/281/2015/bg-12-281-2015.pdf |
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