Witness Community Highlights

Winter thermal contraction cracking and subsequent spring meltwater infiltration produce the ice wedge polygons prevalent in Arctic terrestrial permafrost systems. Point measurements of physical characteristics and carbon dioxide and methane fluxes in low- and high-centered ice wedge polygon sites enable a better understanding of micro-topography ecosystem processes and of the environmental responses to degrading permafrost.

By Melissa Ward Jones, Institute of Northern Engineering, University of Alaska Fairbanks

The NSF supported research group at San Diego State University has used eddy covariance to track Arctic carbon and methane fluxes to gain knowledge of the multi-decadal patterns in these green house gas fluxes. This knowlege is critical to understanding the response to climate variability and long-term change in the carbon balance in the Arctic. Among their findings is that earlier snowmelt is associated with more tundra net carbon sequestration and higher plant productivity only in June and July, but with lower net carbon sequestration and lower plant productivity in August.

By: Donatella Zona, San Diego State University (SDSU) Kyle Lunneberg, SDSU and University of California Davis; and Walter C. Oechel, SDSU