Increases in the flux of carbon belowground stimulate nitrogen uptake and sustain the long-term enhancement of forest productivity under elevated CO2

  • Authors: Drake, John E; Gallet-Budynek, Anne; Hofmockel, Kirsten S; Bernhardt, Emily S; Billings, Sharon A; Jackson, Robert B; Johnsen, Kurt S; et., al.
  • Publication Year: 2011
  • Publication Series: Scientific Journal (JRNL)
  • Source: Ecology Letters Journal 14(4):349-357
  • DOI: 10.1111/j.1461-0248.2011.01593.x

Abstract

The earth’s future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO2. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO2 stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO2 as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil.

  • Citation: Drake, John E; Gallet-Budynek, Anne; Hofmockel, Kirsten S; Bernhardt, Emily S; Billings, Sharon A; Jackson, Robert B; Johnsen, Kurt S; et. al. 2011. Increases in the flux of carbon belowground stimulate nitrogen uptake and sustain the long-term enhancement of forest productivity under elevated CO2. Ecology Letters Journal 14(4):349-357.
  • Keywords: Carbon sequestration;coupled biogeochemical cycles;coupled climate-carbon cycle models;elevated CO2;forest productivity;nitrogen
  • Posted Date: May 19, 2011
  • Modified Date: September 12, 2011
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