TY - JOUR
T1 - Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula
AU - Lara, Mark J.
AU - Mcguire, A. David
AU - Euskirchen, Eugenie S.
AU - Tweedie, Craig E.
AU - Hinkel, Kenneth M.
AU - Skurikhin, Alexei N.
AU - Romanovsky, Vladimir E.
AU - Grosse, Guido
AU - Bolton, W. Robert
AU - Genet, Helene
N1 - Publisher Copyright:
© 2014 John Wiley & Sons Ltd.
PY - 2015/4/1
Y1 - 2015/4/1
N2 - The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30 × 30 m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our ~1800 km2 study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006-2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 106gC-CO2 day-1 (uncertainty using 95% CI is between -438.3 and -1366 106gC-CO2 day-1) and CH4 flux at 28.9 106gC-CH4 day-1(uncertainty using 95% CI is between 12.9 and 44.9 106gC-CH4 day-1), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2 uptake (-166.9 106gC-CO2 day-1) and CH4 flux (2.8 106gC-CH4 day-1) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season.
AB - The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30 × 30 m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our ~1800 km2 study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006-2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 106gC-CO2 day-1 (uncertainty using 95% CI is between -438.3 and -1366 106gC-CO2 day-1) and CH4 flux at 28.9 106gC-CH4 day-1(uncertainty using 95% CI is between 12.9 and 44.9 106gC-CH4 day-1), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2 uptake (-166.9 106gC-CO2 day-1) and CH4 flux (2.8 106gC-CH4 day-1) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season.
KW - Arctic
KW - Carbon balance
KW - Classification
KW - Climate warming
KW - Negative feedback
KW - Polygonal tundra
KW - Thaw-lake cycle
KW - Thermokarst
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U2 - 10.1111/gcb.12757
DO - 10.1111/gcb.12757
M3 - Article
C2 - 25258295
AN - SCOPUS:84924536643
SN - 1354-1013
VL - 21
SP - 1634
EP - 1651
JO - Global change biology
JF - Global change biology
IS - 4
ER -