Dynamics of Carbon Dioxide and Productivity in an Arctic Biosphere

Concentrations of atmospheric CO 2 were measured continuously throughout the 1966 thaw season at two stations on the Arctic coastal plain of Alaska. A seasonal decrease in CO 2 of 15 ppm was demonstrated, as well as changes in concentration associated with storm frequencies and diurnal gradients. Correlation between rate of plant growth and declining CO 2 concentration in the atmosphere was high (r = .98). Tundra growth was initiated by mid—June and was 90% completed in mid—July. Standing crop above ground and below ground was estimated to be 82 and 100 g/m 2 , respectively. A 23% turnover of 273 g/m 2 of litter was confirmed. Gross primary production was estimated at 344 g/m 2 . An annual budget for CO 2 in an Arctic biosphere is postulated and efficiencies for both energy and carbon storage calculated. Based on seasonal net radiation a photosynthetic efficiency of 0.7% was determined, whereas atmospheric CO 2 was apparently used at the rate of nearly 12%. Estimates of CO 2 turnover due to biological activity are similar to the 10—year residence time of a molecule before absorption in the sea.