Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex
We measured seasonal patterns of net ecosystem exchange (NEE) of CO2 in a diverse peatland complex underlain by discontinuous permafrost in northern Manitoba, Canada, as part of the Boreal Ecosystems Atmosphere Study (BOREAS). Study sites spanned the full range of peatland trophic and moisture gradi...
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1998
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ftuninhampshire:oai:scholars.unh.edu:faculty_pubs-1432 2023-05-15T17:58:14+02:00 Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex Bubier, Jill L. Crill, Patrick M. Moore, Tim R. Savage, Kathleen Varner, Ruth K. 1998-12-01T08:00:00Z application/pdf https://scholars.unh.edu/faculty_pubs/433 https://scholars.unh.edu/cgi/viewcontent.cgi?article=1432&context=faculty_pubs unknown University of New Hampshire Scholars' Repository https://scholars.unh.edu/faculty_pubs/433 https://scholars.unh.edu/cgi/viewcontent.cgi?article=1432&context=faculty_pubs Copyright 1998 by the American Geophysical Union. Faculty Publications text 1998 ftuninhampshire 2023-01-30T21:50:01Z We measured seasonal patterns of net ecosystem exchange (NEE) of CO2 in a diverse peatland complex underlain by discontinuous permafrost in northern Manitoba, Canada, as part of the Boreal Ecosystems Atmosphere Study (BOREAS). Study sites spanned the full range of peatland trophic and moisture gradients found in boreal environments from bog (pH 3.9) to rich fen (pH 7.2). During midseason (July‐August, 1996), highest rates of NEE and respiration followed the trophic sequence of bog (5.4 to −3.9 μmol CO2 m−2 s−1) < poor fen (6.3 to −6.5 μmol CO2 m−2 s−1) < intermediate fen (10.5 to −7.8 μmol CO2 m−2 s−1) < rich fen (14.9 to −8.7 μmol CO2m−2 s−1). The sequence changed during spring (May‐June) and fall (September‐October) when ericaceous shrub (e.g., Chamaedaphne calyculata) bogs and sedge (Carex spp.) communities in poor to intermediate fens had higher maximum CO2 fixation rates than deciduous shrub‐dominated (Salix spp. and Betula spp.) rich fens. Timing of snowmelt and differential rates of peat surface thaw in microtopographic hummocks and hollows controlled the onset of carbon uptake in spring. Maximum photosynthesis and respiration were closely correlated throughout the growing season with a ratio of approximately 1/3 ecosystem respiration to maximum carbon uptake at all sites across the trophic gradient. Soil temperatures above the water table and timing of surface thaw and freeze‐up in the spring and fall were more important to net CO2 exchange than deep soil warming. This close coupling of maximum CO2 uptake and respiration to easily measurable variables, such as trophic status, peat temperature, and water table, will improve models of wetland carbon exchange. Although trophic status, aboveground net primary productivity, and surface temperatures were more important than water level in predicting respiration on a daily basis, the mean position of the water table was a good predictor (r2 = 0.63) of mean respiration rates across the range of plant community and moisture gradients. Q10 values ranged ... Text permafrost University of New Hampshire: Scholars Repository Boreas ENVELOPE(-3.933,-3.933,-71.300,-71.300) Canada |
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Open Polar |
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University of New Hampshire: Scholars Repository |
op_collection_id |
ftuninhampshire |
language |
unknown |
description |
We measured seasonal patterns of net ecosystem exchange (NEE) of CO2 in a diverse peatland complex underlain by discontinuous permafrost in northern Manitoba, Canada, as part of the Boreal Ecosystems Atmosphere Study (BOREAS). Study sites spanned the full range of peatland trophic and moisture gradients found in boreal environments from bog (pH 3.9) to rich fen (pH 7.2). During midseason (July‐August, 1996), highest rates of NEE and respiration followed the trophic sequence of bog (5.4 to −3.9 μmol CO2 m−2 s−1) < poor fen (6.3 to −6.5 μmol CO2 m−2 s−1) < intermediate fen (10.5 to −7.8 μmol CO2 m−2 s−1) < rich fen (14.9 to −8.7 μmol CO2m−2 s−1). The sequence changed during spring (May‐June) and fall (September‐October) when ericaceous shrub (e.g., Chamaedaphne calyculata) bogs and sedge (Carex spp.) communities in poor to intermediate fens had higher maximum CO2 fixation rates than deciduous shrub‐dominated (Salix spp. and Betula spp.) rich fens. Timing of snowmelt and differential rates of peat surface thaw in microtopographic hummocks and hollows controlled the onset of carbon uptake in spring. Maximum photosynthesis and respiration were closely correlated throughout the growing season with a ratio of approximately 1/3 ecosystem respiration to maximum carbon uptake at all sites across the trophic gradient. Soil temperatures above the water table and timing of surface thaw and freeze‐up in the spring and fall were more important to net CO2 exchange than deep soil warming. This close coupling of maximum CO2 uptake and respiration to easily measurable variables, such as trophic status, peat temperature, and water table, will improve models of wetland carbon exchange. Although trophic status, aboveground net primary productivity, and surface temperatures were more important than water level in predicting respiration on a daily basis, the mean position of the water table was a good predictor (r2 = 0.63) of mean respiration rates across the range of plant community and moisture gradients. Q10 values ranged ... |
format |
Text |
author |
Bubier, Jill L. Crill, Patrick M. Moore, Tim R. Savage, Kathleen Varner, Ruth K. |
spellingShingle |
Bubier, Jill L. Crill, Patrick M. Moore, Tim R. Savage, Kathleen Varner, Ruth K. Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
author_facet |
Bubier, Jill L. Crill, Patrick M. Moore, Tim R. Savage, Kathleen Varner, Ruth K. |
author_sort |
Bubier, Jill L. |
title |
Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
title_short |
Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
title_full |
Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
title_fullStr |
Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
title_full_unstemmed |
Seasonal patterns and controls on net ecosystem CO2 exchange in a boreal peatland complex |
title_sort |
seasonal patterns and controls on net ecosystem co2 exchange in a boreal peatland complex |
publisher |
University of New Hampshire Scholars' Repository |
publishDate |
1998 |
url |
https://scholars.unh.edu/faculty_pubs/433 https://scholars.unh.edu/cgi/viewcontent.cgi?article=1432&context=faculty_pubs |
long_lat |
ENVELOPE(-3.933,-3.933,-71.300,-71.300) |
geographic |
Boreas Canada |
geographic_facet |
Boreas Canada |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Faculty Publications |
op_relation |
https://scholars.unh.edu/faculty_pubs/433 https://scholars.unh.edu/cgi/viewcontent.cgi?article=1432&context=faculty_pubs |
op_rights |
Copyright 1998 by the American Geophysical Union. |
_version_ |
1766166793505734656 |