Increasing atmospheric carbon dioxide: possible effects on arctic tundra.

Cores of wet coastal tundra collected in frozen condition in winter were used as microcosms in a phytotron experiment that assessed the effects of doubling the present atmospheric CO concentration, increasing temperature, and depressed water table on net ecosystem CO exchange. Doubling atmospheric CO had less significance in regard to net carbon capture or loss in this ecosystem as compared to the significant effects of increased temperature and lowered water table level. Both of the latter are to be expected as atmospheric CO increases in the Arctic.