Materials and Methods of the Barrow Manipulation Site

	The tundra elevated soil temperature and water table manipulation site was 
located near Barrow, Alaska (71 19 18.36 N, 156 37 6.35 W).  Eighteen 60 cm 
diameter polycarbonate cylinders were installed into the ground at the end of the 1998 
growing season when thaw depth was at its seasonal maximum to isolate plots of tundra 
and was organized into three blocks of six for three replicates of the six treatments to be 
tested.  The six factors that are being tested include: control, elevated water table, 
lowered water table, elevated soil temperature, elevated soil temperature and elevated 
water table, and elevated soil temperature and lowered water table.  Temperature data 
was collected from June, 1999 until September 2001.  There are six type-t thermocouples 
in each plot, four in the center and two at the edge.  The depths of the center probes are 1 
cm, 5 cm, 15 cm, and 25 cm.  For the probes at the edge of the plots, they are at 5 cm and 
15 cm depth.  Data was collected in half-hour intervals by a 23X datalogger (Campbell 
Scientific, Inc.).  Blank areas in the data are due to power failure or other loss beyond our 
control.  Soil heating was accomplished by the use of silicone rubber heaters (Omegalux, 
Inc., 5.0 W m-2) affixed to the inner surface of the cylinders.  Heating treatments are 
maintained so that soil temperature was 5?C warmer than ambient soil temperatures 
during the 1999 season and 3?C warmer than ambient during the 2000 and 2001 seasons.  
Water table drainage was maintained through the use of float switch activated water 
pumps (Rule Inc., 500 gph) within perforated PVC pipe water wells within each plot 
while in elevated water table treatments water will be pumped into identical wells from 
an outside reservoir.