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.
Bronson
Dustin R
DR
Department of Renewable Resources, 1000 E. University Avenue, University of Wyoming, Laramie, WY 82071, USA. dustin.bronson@uwyo.edu
Gower
Stith T
ST
D000064:Acclimatization; D052818:Autotrophic Processes; D019069:Cell Respiration; D017753:Ecosystem; D057232:Global Warming; D008350:Manitoba; D010788:Photosynthesis; D028222:Picea / Q000378:metabolism*; D014887:Weather