Process-Oriented Modeling of a High Arctic Tundra Ecosystem: Long-Term Carbon Budget and Ecosystem Responses to Interannual Variations of Climate

2018 ◽  
Vol 123 (4) ◽  
pp. 1178-1196 ◽  
Author(s):  
Wenxin Zhang ◽  
Per-Erik Jansson ◽  
Guy Schurgers ◽  
Jørgen Hollesen ◽  
Magnus Lund ◽  
...  
Keyword(s):  
Carbon Budget ◽  
Arctic Tundra ◽  
High Arctic ◽  
Interannual Variations ◽  
Ecosystem Responses ◽  
Tundra Ecosystem ◽  
Process Oriented

Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

2016 ◽  
Vol 121 (5) ◽  
pp. 1236-1248 ◽  
Author(s):  
Philipp R. Semenchuk ◽  
Casper T. Christiansen ◽  
Paul Grogan ◽  
Bo Elberling ◽  
Elisabeth J. Cooper
Keyword(s):  
Growing Season ◽  
Arctic Tundra ◽  
High Arctic ◽  
Tundra Ecosystem

scholarly journals Two years with extreme and little snowfall: effects on energy partitioning and surface energy exchange in a high-Arctic tundra ecosystem

2016 ◽  
Vol 10 (4) ◽  
pp. 1395-1413 ◽  
Author(s):  
Christian Stiegler ◽  
Magnus Lund ◽  
Torben Røjle Christensen ◽  
Mikhail Mastepanov ◽  
Anders Lindroth
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Snow Cover ◽  
Energy Exchange ◽  
Surface Energy Balance ◽  
Arctic Tundra ◽  
High Arctic ◽  
Snow Accumulation ◽  
Heat Fluxes ◽  
Tundra Ecosystem

Abstract. Snow cover is one of the key factors controlling Arctic ecosystem functioning and productivity. In this study we assess the impact of strong variability in snow accumulation during 2 subsequent years (2013–2014) on the land–atmosphere interactions and surface energy exchange in two high-Arctic tundra ecosystems (wet fen and dry heath) in Zackenberg, Northeast Greenland. We observed that record-low snow cover during the winter 2012/2013 resulted in a strong response of the heath ecosystem towards low evaporative capacity and substantial surface heat loss by sensible heat fluxes (H) during the subsequent snowmelt period and growing season. Above-average snow accumulation during the winter 2013/2014 promoted summertime ground heat fluxes (G) and latent heat fluxes (LE) at the cost of H. At the fen ecosystem a more muted response of LE, H and G was observed in response to the variability in snow accumulation. Overall, the differences in flux partitioning and in the length of the snowmelt periods and growing seasons during the 2 years had a strong impact on the total accumulation of the surface energy balance components. We suggest that in a changing climate with higher temperature and more precipitation the surface energy balance of this high-Arctic tundra ecosystem may experience a further increase in the variability of energy accumulation, partitioning and redistribution.

scholarly journals Quantifying Muskox Plant Biomass Removal and Spatial Relocation of Nitrogen in a High Arctic Tundra Ecosystem

2016 ◽  
Vol 48 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Jesper B. Mosbacher ◽  
Ditte K. Kristensen ◽  
Anders Michelsen ◽  
Mikkel Stelvig ◽  
Niels M. Schmidt
Keyword(s):  
Plant Biomass ◽  
Arctic Tundra ◽  
High Arctic ◽  
Tundra Ecosystem ◽  
Biomass Removal

scholarly journals The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

2015 ◽  
Vol 12 (23) ◽  
pp. 19781-19817
Author(s):  
A. E. Cassidy ◽  
A. Christen ◽  
G. H. R. Henry
Keyword(s):  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
Growing Season ◽  
Arctic Tundra ◽  
High Arctic ◽  
Carbon Dioxide Fluxes ◽  
Tundra Ecosystem ◽  
Retrogressive Thaw Slump ◽  
Measurement Period

Abstract. Soil carbon stored in high-latitude permafrost landscapes is threatened by warming, and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, have increased in frequency and magnitude across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season the undisturbed tundra was a small net sink (NEE = −0.12 g C m−2 d−1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.39 g C m−2 d−1). Over the measurement period, the undisturbed tundra sequestered 3.84 g C m−2, while the disturbed tundra released 12.48 g C m−2. Before full leaf out in early July, the undisturbed tundra was a small source of CO2, but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.41 μmol m−2 s−1 and +0.50 μmol m−2 s−1, respectively) than those found in undisturbed tundra (+1.21 μmol m−2 s−1 and +1.00 μmol m−2 s−1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the growing season.

scholarly journals The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

2016 ◽  
Vol 13 (8) ◽  
pp. 2291-2303 ◽  
Author(s):  
Alison E. Cassidy ◽  
Andreas Christen ◽  
Gregory H. R. Henry
Keyword(s):  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
Growing Season ◽  
Arctic Tundra ◽  
High Arctic ◽  
Carbon Dioxide Fluxes ◽  
Tundra Ecosystem ◽  
Retrogressive Thaw Slump ◽  
Measurement Period

Abstract. Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are present across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season, the undisturbed tundra was a small net sink (NEE  =  −0.1 g C m−2 d−1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE  =  +0.4 g C m−2 d−1). Over the measurement period, the undisturbed tundra sequestered 3.8 g C m−2, while the disturbed tundra released 12.5 g C m−2. Before full leaf-out in early July, the undisturbed tundra was a small source of CO2 but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure daytime fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.40 µmol m−2 s−1 and +0.55 µmol m−2 s−1, respectively) than those found in undisturbed tundra (+1.19 µmol m−2 s−1 and +1.04 µmol m−2 s−1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the majority of the growing season (late June and July).

scholarly journals Ecosystem responses to climate change at a Low Arctic and a High Arctic long-term research site

AMBIO ◽  
2017 ◽  
Vol 46 (S1) ◽  
pp. 160-173 ◽  
Author(s):  
John E. Hobbie ◽  
Gaius R. Shaver ◽  
Edward B. Rastetter ◽  
Jessica E. Cherry ◽  
Scott J. Goetz ◽  
...  
Keyword(s):  
Climate Change ◽  
High Arctic ◽  
Ecosystem Responses ◽  
Research Site ◽  
Low Arctic

scholarly journals Short-term herbivory has long-term consequences in warmed and ambient high Arctic tundra

2017 ◽  
Vol 12 (2) ◽  
pp. 025001 ◽  
Author(s):  
Chelsea J Little ◽  
Helen Cutting ◽  
Juha Alatalo ◽  
Elisabeth J Cooper
Keyword(s):  
Arctic Tundra ◽  
High Arctic ◽  
Short Term ◽  
Long Term Consequences

Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling

Ecology ◽  
2012 ◽  
Vol 93 (7) ◽  
pp. 1707-1716 ◽  
Author(s):  
P. Legagneux ◽  
G. Gauthier ◽  
D. Berteaux ◽  
J. Bêty ◽  
M.-C. Cadieux ◽  
...  
Keyword(s):  
Food Web ◽  
Arctic Tundra ◽  
High Arctic ◽  
Trophic Relationships ◽  
Tundra Ecosystem
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