ARCSS006: Ecosystem Carbon Fluxes, Toolik Lake, Alaska, 1995 and 1996
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Steven Oberbauer, Florida International University

Carbon dioxide information was collected at the Toolik Lake 
Field Station during the summers of 1995 and 1996 from plots
located on the east-facing slope above the entrance stream
to the lake. Included are the following parameters: Julian day, 
treatment, set, plot, photosynthetically active radiation (PAR),
air temperature, and CO2 exchange (with a precision of 
0.2 umol/m2/s). Treatments were control, snow removal, and 
snow removal plus soil heating. Soil heating was done at 
10 cm depth using greenhouse cold frame heating cables, and 
plots were heated 2 hours per day. Six replicates of each 
treatment were set up in randomized blocks located 3 m apart. 
Once a week each 1.5m x 1.5m plot was analyzed every four hours 
during the day, or less frequently depending on rainfall delays. 
In 1995, snow was removed from the plots on May 3 and May 12, with 
subsequent soil heating beginning on May 12. In 1996, snow was 
removed from the plots on May 3, and soil heating started on 
May 5. 

A closed system gas exchange using a Li-Cor 6200 portable gas exchange 
system attached to a 70 X 70 X 40 cm polycarbonate ventilated chamber
was used to measure CO2 flux. The chamber was sealed to a polyacrylic 
or polypropylene base buried 20 cm deep. Measurements were made with 
30 second incubation times with 3 observations per plot. The last two 
observations were meaned for the final value presented in the files. 
Photosynthetically active radiation was measured with the Li-Cor 
quantum sensor on the cuvette by placing the sensor above the chamber 
prior to measurement. Air temperature was measured with thermocouple 
within the chamber continuously during observations.

Data files are in both ASCII (ecocrflux95.dat, ecocrflux96.dat) and 
MS Excel (ecocrflx95.xls, ecocrflx96.xls) formats.