Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

CO2 Flux in Arctic and Alpine Dry Tundra: Comparative Field Responses under Ambient and Experimentally Warmed Conditions

J. M. Welker, K. B. Brown and J. T. Fahnestock
Arctic, Antarctic, and Alpine Research
Vol. 31, No. 3 (Aug., 1999), pp. 272-277
DOI: 10.2307/1552257
Stable URL: http://www.jstor.org/stable/1552257
Page Count: 6
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
CO2 Flux in Arctic and Alpine Dry Tundra: Comparative Field Responses under Ambient and Experimentally Warmed Conditions
Preview not available

Abstract

We compared growing season CO2 flux patterns between botanically similar arctic and alpine dry tundra ecosystems in Alaska and Colorado under ambient and experimentally warmed conditions. Measurements were taken during the 1997 growing season, 3 yr after the warming treatments were begun. Under ambient weather conditions, arctic dry tundra at Toolik Lake, Alaska was a net source (4 g CO2-C m-2) of CO2 to the atmosphere, while alpine dry tundra at Niwot Ridge, Colorado, was a net CO2 sink (7 g CO2-C m-2) during the growing season. Experimental warming of arctic tundra by 1 to 3°C, resulted in a seven-fold (32 g CO2-C m-2) increase in this ecosystem's carbon source activity. Similar warming in alpine tundra changed this ecosystem from a net carbon sink to a net carbon source of 8 g CO2-C m-2 over the growing season. In the Arctic, increased CO2 efflux with warming was largely the result of increased rates of ecosystem respiration throughout the entire growing season, while in the alpine ecosystem respiration increased only early in the growing season. Rates of photosynthesis were generally not affected by experimental warming at either site. These data suggest that global warming will accentuate the carbon source activity of dry tundra in the northern foothills of Alaska and will change the net CO2 exchange of alpine dry tundra in the northern Rocky Mountains from a net CO2 sink to a source.

Page Thumbnails

  • Thumbnail: Page 
272
    272
  • Thumbnail: Page 
273
    273
  • Thumbnail: Page 
274
    274
  • Thumbnail: Page 
275
    275
  • Thumbnail: Page 
276
    276
  • Thumbnail: Page 
277
    277