Effects of permafrost melting on CO2 and CH4 exchange of a poorly drained black spruce lowland
Article first published online: 2 JUN 2006
Copyright 2006 by the American Geophysical Union.
Journal of Geophysical Research: Biogeosciences (2005–2012)
Volume 111, Issue G2, June 2006
How to Cite
2006), Effects of permafrost melting on CO2 and CH4 exchange of a poorly drained black spruce lowland, J. Geophys. Res., 111, G02011, doi:10.1029/2005JG000099., , , and (
- Issue published online: 2 JUN 2006
- Article first published online: 2 JUN 2006
- Manuscript Accepted: 22 FEB 2006
- Manuscript Revised: 8 FEB 2006
- Manuscript Received: 7 SEP 2005
- carbon cycling;
- black spruce
 Permafrost melting is occurring in areas of the boreal forest region where large amounts of carbon (C) are stored in organic soils. We measured soil respiration, net CO2 flux, and net CH4 flux during May–September 2003 and March 2004 in a black spruce lowland in interior Alaska to better understand how permafrost thaw in poorly drained landscapes affects land-atmosphere CO2 and CH4 exchange. Sites included peat soils underlain by permafrost at ∼0.4 m depth (permafrost plateau, PP), four thermokarst wetlands (TW) having no permafrost in the upper 2.2 m, and peat soils bordering the thermokarst wetlands having permafrost at ∼0.5 m depth (thermokarst edges, TE). Soil respiration rates were not significantly different among the sites, and 5-cm soil temperature explained 50–91% of the seasonal variability in soil respiration within the sites. Groundcover vegetation photosynthesis (calculated as net CO2 minus soil respiration) was significantly different among the sites (TW > TE > PP), which can be partly attributed to the difference in photosynthetically active radiation reaching the ground at each site type. Methane emission rates were 15 to 28 times greater from TW than from TE and PP. We modeled annual soil respiration and groundcover vegetation photosynthesis using soil temperature and radiation data, and CH4 flux by linear interpolation. We estimated all sites as net C gas sources to the atmosphere (not including tree CO2 uptake at PP and TE), although the ranges in estimates when accounting for errors were large enough that TE and TW may have been net C sinks.