Ecosystem warming does not affect photosynthesis or aboveground autotrophic respiration for boreal black spruce.
We measured light-saturated photosynthesis (A(net)), foliage respiration (R(fol)) and stem respiration (R(stem)) of black spruce (Picea mariana (Mill.) B.S.P.) in heated (+5 degrees C) and control plots during 2005, 2006 and 2007 in Thompson, MB, Canada. Large greenhouses and soil-heating cables were used to maintain air and soil temperature 5 degrees C above ambient air and soil temperature. Each greenhouse contained approximately nine black spruce trees and the majority of their fine root mass. Treatments were soil and air warming, soil-only warming, greenhouses maintained at ambient air temperature and control. Gas exchange rates ranged 0.71-4.66, 0.04-0.74 and 0.1-1.0 micromol m(-)(2) s(-)(1) for A(net), R(fol) and R(stem), respectively. Treatment differences for A(net), R(fol) and R(stem) were not significant in any of the 3 years of measurements. The results of this experiment suggest that in a warmer climate, black spruce may not have significant changes in the rate of photosynthesis or respiration.
Department of Renewable Resources, 1000 E. University Avenue, University of Wyoming, Laramie, WY 82071, USA. dustin.bronson@uwyo.edu
Dustin R
DR
Bronson
Stith T
ST
Gower
D000064:Acclimatization; D052818:Autotrophic Processes; D019069:Cell Respiration; D017753:Ecosystem; D057232:Global Warming; D008350:Manitoba; D010788:Photosynthesis; D028222:Picea / Q000378:metabolism*; D014887:Weather