Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements
CO 2 and CH 4 exchange are strongly affected by hydrology in landscapes underlain by permafrost. Hypotheses for these effects in the model ecosys were tested by comparing modeled CO 2 and CH 4 exchange with CO 2 fluxes measured by eddy covariance from 2006 to 2009, and with CH 4 fluxes measured with...
Published in: | Journal of Geophysical Research: Biogeosciences |
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Online Access: | https://ir.library.carleton.ca/pub/8621 https://doi.org/10.1002/2014JG002888 |
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ftcarletonunivir:oai:carleton.ca:8621 2023-05-15T15:12:16+02:00 Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements Grant, R.F. Humphreys, E. (Elyn) LaFleur, P.M. 2015-07-01 application/pdf https://ir.library.carleton.ca/pub/8621 https://doi.org/10.1002/2014JG002888 en eng https://ir.library.carleton.ca/pub/8621 doi:10.1002/2014JG002888 info:eu-repo/semantics/openAccess Journal of Geophysical Research G: Biogeosciences vol. 120 no. 7, pp. 1366-1387 active layer depth ecosys fen modeling net ecosystem productivity tundra info:eu-repo/semantics/article 2015 ftcarletonunivir https://doi.org/10.1002/2014JG002888 2022-02-06T21:51:19Z CO 2 and CH 4 exchange are strongly affected by hydrology in landscapes underlain by permafrost. Hypotheses for these effects in the model ecosys were tested by comparing modeled CO 2 and CH 4 exchange with CO 2 fluxes measured by eddy covariance from 2006 to 2009, and with CH 4 fluxes measured with surface chambers in 2008, along a topographic gradient at Daring Lake, NWT. In an upland tundra, rises in net CO 2 uptake in warmer years were constrained by declines in CO 2 influxes when vapor pressure deficits (D) exceeded 1.5kPa and by rises in CO 2 effluxes with greater active layer depth. Consequently, net CO 2 uptake rose little with warming. In a lowland fen, CO 2 influxes declined less with D and CO 2 effluxes rose less with warming, so that rises in net CO 2 uptake were greater than those in the tundra. Greater declines in CO 2 influxes with warming in the tundra were modeled from greater soil-plant-atmosphere water potential gradients that developed under higher D in drained upland soil, and smaller rises in CO 2 effluxes with warming in the fen were modeled from O 2 constraints to heterotrophic and belowground autotrophic respiration from a shallow water table in poorly drained lowland soil. CH 4 exchange modeled during July and August indicated very small influxes in the tundra and larger effluxes characterized by afternoon emission events caused by degassing of warming soil in the fen. Emissions of CH 4 modeled from degassing during soil freezing in October-November contributed about one third of the annual total. Article in Journal/Newspaper Arctic permafrost Tundra Carleton University's Institutional Repository Arctic Daring Lake ENVELOPE(-111.635,-111.635,64.834,64.834) Journal of Geophysical Research: Biogeosciences 120 7 1366 1387 |
institution |
Open Polar |
collection |
Carleton University's Institutional Repository |
op_collection_id |
ftcarletonunivir |
language |
English |
topic |
active layer depth ecosys fen modeling net ecosystem productivity tundra |
spellingShingle |
active layer depth ecosys fen modeling net ecosystem productivity tundra Grant, R.F. Humphreys, E. (Elyn) LaFleur, P.M. Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
topic_facet |
active layer depth ecosys fen modeling net ecosystem productivity tundra |
description |
CO 2 and CH 4 exchange are strongly affected by hydrology in landscapes underlain by permafrost. Hypotheses for these effects in the model ecosys were tested by comparing modeled CO 2 and CH 4 exchange with CO 2 fluxes measured by eddy covariance from 2006 to 2009, and with CH 4 fluxes measured with surface chambers in 2008, along a topographic gradient at Daring Lake, NWT. In an upland tundra, rises in net CO 2 uptake in warmer years were constrained by declines in CO 2 influxes when vapor pressure deficits (D) exceeded 1.5kPa and by rises in CO 2 effluxes with greater active layer depth. Consequently, net CO 2 uptake rose little with warming. In a lowland fen, CO 2 influxes declined less with D and CO 2 effluxes rose less with warming, so that rises in net CO 2 uptake were greater than those in the tundra. Greater declines in CO 2 influxes with warming in the tundra were modeled from greater soil-plant-atmosphere water potential gradients that developed under higher D in drained upland soil, and smaller rises in CO 2 effluxes with warming in the fen were modeled from O 2 constraints to heterotrophic and belowground autotrophic respiration from a shallow water table in poorly drained lowland soil. CH 4 exchange modeled during July and August indicated very small influxes in the tundra and larger effluxes characterized by afternoon emission events caused by degassing of warming soil in the fen. Emissions of CH 4 modeled from degassing during soil freezing in October-November contributed about one third of the annual total. |
format |
Article in Journal/Newspaper |
author |
Grant, R.F. Humphreys, E. (Elyn) LaFleur, P.M. |
author_facet |
Grant, R.F. Humphreys, E. (Elyn) LaFleur, P.M. |
author_sort |
Grant, R.F. |
title |
Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
title_short |
Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
title_full |
Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
title_fullStr |
Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
title_full_unstemmed |
Ecosystem CO2 and CH4 exchange in a mixed tundra and a fen within a hydrologically diverse Arctic landscape: 1. Modeling versus measurements |
title_sort |
ecosystem co2 and ch4 exchange in a mixed tundra and a fen within a hydrologically diverse arctic landscape: 1. modeling versus measurements |
publishDate |
2015 |
url |
https://ir.library.carleton.ca/pub/8621 https://doi.org/10.1002/2014JG002888 |
long_lat |
ENVELOPE(-111.635,-111.635,64.834,64.834) |
geographic |
Arctic Daring Lake |
geographic_facet |
Arctic Daring Lake |
genre |
Arctic permafrost Tundra |
genre_facet |
Arctic permafrost Tundra |
op_source |
Journal of Geophysical Research G: Biogeosciences vol. 120 no. 7, pp. 1366-1387 |
op_relation |
https://ir.library.carleton.ca/pub/8621 doi:10.1002/2014JG002888 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/2014JG002888 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
120 |
container_issue |
7 |
container_start_page |
1366 |
op_container_end_page |
1387 |
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1766342979502473216 |