Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing
The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze– thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO2 from 2012 to...
Published in: | Global Change Biology |
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2018
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Online Access: | https://doi.org/10.1111/gcb.14283 http://handle.westernsydney.edu.au:8081/1959.7/uws:48690 |
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ftunivwestsyd:oai:researchdirect.westernsydney.edu.au:uws_48690 2023-05-15T17:40:14+02:00 Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing Parazoo, Nicholas C. Arneth, Almuth Pugh, Thomas A. Smith, Benjamin (R19508) Steiner, Nicholas Luus, Kristina A. Commane, Roisin Benmergui, Joshua Stofferahn, Eric Liu, Junjie Rodenbeck, Christian Kawa, Randy Euskirchen, Eugenie S. Zona, Donatella Arndt, Kyle Oechel, Walt C. Miller, Charles E. Hawkesbury Institute for the Environment (Host institution) 2018 print 20 https://doi.org/10.1111/gcb.14283 http://handle.westernsydney.edu.au:8081/1959.7/uws:48690 eng eng U.K., Wiley-Blackwell Publishing Global Change Biology--1354-1013--1365-2486 Vol. 24 Issue. 8 No. pp: 3416-3435 XXXXXX - Unknown carbon cycle (biogeochemistry) remote sensing permafrost taigas photosynthesis thawing Alaska journal article 2018 ftunivwestsyd https://doi.org/10.1111/gcb.14283 2020-12-05T17:55:39Z The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze– thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO2 from 2012 to 2014 indicating the timing and magnitude of spring carbon uptake in Alaska correlates with landscape thaw and ecoregion. Landscape thaw in boreal forests typically occurs in late April (DOY 111 _ 7) with a 29 _ 6 day lag until photosynthetic onset. North Slope tundra thaws 3 weeks later (DOY 133 _ 5) but experiences only a 20 _ 5 day lag until photosynthetic onset. These time lag differences reflect efficient cold season adaptation in tundra shrub and the longer dehardening period for boreal evergreens. Despite the short transition from thaw to photosynthetic onset in tundra, synchrony of tundra respiration with snow melt and landscape thaw delays the transition from net carbon loss (at photosynthetic onset) to net uptake by 13 _ 7 days, thus reducing the tundra net carbon uptake period. Two global CO2 inversions using a CASAGFED model prior estimate earlier northern high latitude net carbon uptake compared to our regional inversion, which we attribute to (i) early photosynthetic-onset model prior bias, (ii) inverse method (scaling factor + optimization window), and (iii) sparsity of available Alaskan CO2 observations. Another global inversion with zero prior estimates the same timing for net carbon uptake as the regional model but smaller seasonal amplitude. The analysis of Alaskan eddy covariance observations confirms regional scale findings for tundra, but indicates that photosynthesis and net carbon uptake occur up to 1 month earlier in evergreens than captured by models or CO2 inversions, with better correlation to above-freezing air temperature than date of primary thaw. Further collection and analysis of boreal evergreen species over multiple years and at additional subarctic flux towers are critically needed. Article in Journal/Newspaper north slope permafrost Subarctic Tundra Alaska University of Western Sydney (UWS): Research Direct Global Change Biology 24 8 3416 3435 |
institution |
Open Polar |
collection |
University of Western Sydney (UWS): Research Direct |
op_collection_id |
ftunivwestsyd |
language |
English |
topic |
XXXXXX - Unknown carbon cycle (biogeochemistry) remote sensing permafrost taigas photosynthesis thawing Alaska |
spellingShingle |
XXXXXX - Unknown carbon cycle (biogeochemistry) remote sensing permafrost taigas photosynthesis thawing Alaska Parazoo, Nicholas C. Arneth, Almuth Pugh, Thomas A. Smith, Benjamin (R19508) Steiner, Nicholas Luus, Kristina A. Commane, Roisin Benmergui, Joshua Stofferahn, Eric Liu, Junjie Rodenbeck, Christian Kawa, Randy Euskirchen, Eugenie S. Zona, Donatella Arndt, Kyle Oechel, Walt C. Miller, Charles E. Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
topic_facet |
XXXXXX - Unknown carbon cycle (biogeochemistry) remote sensing permafrost taigas photosynthesis thawing Alaska |
description |
The springtime transition to regional-scale onset of photosynthesis and net ecosystem carbon uptake in boreal and tundra ecosystems are linked to the soil freeze– thaw state. We present evidence from diagnostic and inversion models constrained by satellite fluorescence and airborne CO2 from 2012 to 2014 indicating the timing and magnitude of spring carbon uptake in Alaska correlates with landscape thaw and ecoregion. Landscape thaw in boreal forests typically occurs in late April (DOY 111 _ 7) with a 29 _ 6 day lag until photosynthetic onset. North Slope tundra thaws 3 weeks later (DOY 133 _ 5) but experiences only a 20 _ 5 day lag until photosynthetic onset. These time lag differences reflect efficient cold season adaptation in tundra shrub and the longer dehardening period for boreal evergreens. Despite the short transition from thaw to photosynthetic onset in tundra, synchrony of tundra respiration with snow melt and landscape thaw delays the transition from net carbon loss (at photosynthetic onset) to net uptake by 13 _ 7 days, thus reducing the tundra net carbon uptake period. Two global CO2 inversions using a CASAGFED model prior estimate earlier northern high latitude net carbon uptake compared to our regional inversion, which we attribute to (i) early photosynthetic-onset model prior bias, (ii) inverse method (scaling factor + optimization window), and (iii) sparsity of available Alaskan CO2 observations. Another global inversion with zero prior estimates the same timing for net carbon uptake as the regional model but smaller seasonal amplitude. The analysis of Alaskan eddy covariance observations confirms regional scale findings for tundra, but indicates that photosynthesis and net carbon uptake occur up to 1 month earlier in evergreens than captured by models or CO2 inversions, with better correlation to above-freezing air temperature than date of primary thaw. Further collection and analysis of boreal evergreen species over multiple years and at additional subarctic flux towers are critically needed. |
author2 |
Hawkesbury Institute for the Environment (Host institution) |
format |
Article in Journal/Newspaper |
author |
Parazoo, Nicholas C. Arneth, Almuth Pugh, Thomas A. Smith, Benjamin (R19508) Steiner, Nicholas Luus, Kristina A. Commane, Roisin Benmergui, Joshua Stofferahn, Eric Liu, Junjie Rodenbeck, Christian Kawa, Randy Euskirchen, Eugenie S. Zona, Donatella Arndt, Kyle Oechel, Walt C. Miller, Charles E. |
author_facet |
Parazoo, Nicholas C. Arneth, Almuth Pugh, Thomas A. Smith, Benjamin (R19508) Steiner, Nicholas Luus, Kristina A. Commane, Roisin Benmergui, Joshua Stofferahn, Eric Liu, Junjie Rodenbeck, Christian Kawa, Randy Euskirchen, Eugenie S. Zona, Donatella Arndt, Kyle Oechel, Walt C. Miller, Charles E. |
author_sort |
Parazoo, Nicholas C. |
title |
Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
title_short |
Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
title_full |
Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
title_fullStr |
Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
title_full_unstemmed |
Spring photosynthetic onset and net CO2 uptake in Alaska triggered by landscape thawing |
title_sort |
spring photosynthetic onset and net co2 uptake in alaska triggered by landscape thawing |
publisher |
U.K., Wiley-Blackwell Publishing |
publishDate |
2018 |
url |
https://doi.org/10.1111/gcb.14283 http://handle.westernsydney.edu.au:8081/1959.7/uws:48690 |
genre |
north slope permafrost Subarctic Tundra Alaska |
genre_facet |
north slope permafrost Subarctic Tundra Alaska |
op_relation |
Global Change Biology--1354-1013--1365-2486 Vol. 24 Issue. 8 No. pp: 3416-3435 |
op_doi |
https://doi.org/10.1111/gcb.14283 |
container_title |
Global Change Biology |
container_volume |
24 |
container_issue |
8 |
container_start_page |
3416 |
op_container_end_page |
3435 |
_version_ |
1766141112462868480 |