title: Interaction of increasing atmospheric carbon dioxide and soil nitrogen on the carbon balance of tundra microcosms.
abstract: Natural cores of vegetation and soils of arctic tundra were collected in frozen condition in winter near Barrow, Alaska (71°20'N). These cores were used as microcosms in a phytotron experiment to measure the interactions, if any, between increasing atmospheric CO2concentration and fertilization by ammonium nitrate on net ecosystem CO2exchange and net yield of tundra vegetation. Increased soil N significantly enhanced net ecosystem CO2uptake. The effect of increased CO2concentration had little or no effect on mean net ecosystem carbon balance of the tundra microcosms. Added N significantly increased leaf area and phytomass of vascular plants in the microcosms while increased atmospheric CO2had no effect on these parameters. We conclude that atmospheric CO2is not now limiting net ecosystem production in the tundra and that its direct effects will be slight even at double the present concentration. the most probable effects of carbon dioxide in the coastal tundra will be through its indirect effects on temperature, water table, peat decomposition, and the availability of soil nutrients.
authors.affiliation: Department of Botany, Duke University, 27706, Durham, NC, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Billings
authors.affiliation: Department of Biological Sciences, Clemson University, 29631, Clemson, SC, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Peterson
authors.affiliation: Department of Botany, Duke University, 27706, Durham, NC, USA.
authors.forename: J O
authors.initials: JO
authors.lastname: Luken
authors.affiliation: Department of Botany, Duke University, 27706, Durham, NC, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Mortensen