Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost

Journal of Geophysical Research: Biogeosciences
By: , and 

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Abstract

Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of thermokarst, and a rich fen without permafrost. Measurements include year-round eddy covariance estimates of carbon dioxide (CO2), water, and energy fluxes, associated environmental variables, and methane (CH4) fluxes at the collapse scar bog. The ecosystems all acted as net sinks of CO2 in 2011 and 2012, when air temperature and precipitation remained near long-term means. In 2013, under a late snowmelt and late leaf out followed by a hot, dry summer, the permafrost forest and collapse scar bog were sources of CO2. In this same year, CO2 uptake in the fen increased, largely because summer inundation from groundwater inputs suppressed ecosystem respiration. CO2 exchange in the permafrost forest and collapse scar bog was sensitive to warm air temperatures, with 0.5 g C m−2 lost each day when maximum air temperature was very warm (≥29°C). The bog lost 4981 ± 300 mg CH4 m−2 between April and September 2013, indicating that this ecosystem acted as a significant source of both CO2 and CHto the atmosphere in 2013. These results suggest that boreal peatland responses to warming and drying, both of which are expected to occur in a changing climate, will depend on permafrost regime.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost
Series title Journal of Geophysical Research: Biogeosciences
DOI 10.1002/2014JG002683
Volume 119
Issue 8
Year Published 2016
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Science Center
First page 1576
Last page 1595
Country United States
State Alaska
Online Only (Y/N) N
Additional Online Files (Y/N) N