Heterotrophic Respiration and the Divergence of Productivity and Carbon Sequestration

  • Authors: Noormets, Asko; Bracho, Rosvel; Ward, Eric; Seiler, John; Strahm, Brian; Lin, Wen; McElligott, Kristin; Domec, Jean‐Christophe; Gonzalez‐Benecke, Carlos; Jokela, Eric J.; Markewitz, Daniel; Meek, Cassandra; Miao, Guofang; McNulty, Steve G.; King, John S.; Samuelson, Lisa; Sun, Ge; Teskey, Robert; Vogel, Jason; Will, Rodney; Yang, Jinyan; Martin, Timothy A.
  • Publication Year: 2021
  • Publication Series: Scientific Journal (JRNL)
  • Source: Geophysical Research Letters
  • DOI: 10.1029/2020GL092366

Abstract

Net primary productivity (NPP) and net ecosystem production (NEP) are often used interchangeably, as their difference, heterotrophic respiration (soil heterotrophic CO2 efflux, RSH = NPP-NEP), is assumed a near-fixed fraction of NPP. Here, we show, using a range-wide replicated experimental study in loblolly pine (Pinus taeda) plantations that RSH responds differently than NPP to fertilization and drought treatments, leading to the divergent responses of NPP and NEP. Across the natural range of the species, the moderate responses of NPP (+11%) and RSH (-7%) to fertilization combined such that NEP increased nearly threefold in ambient control and 43% under drought treatment. A 13% decline in RSH under drought led to a 26% increase in NEP while NPP was unaltered. Such drought benefit for carbon sequestration was nearly twofold in control, but disappeared under fertilization. Carbon sequestration efficiency, NEP:NPP, varied twofold among sites, and increased up to threefold under both drought and fertilization.

  • Citation: Noormets, Asko; Bracho, Rosvel; Ward, Eric; Seiler, John; Strahm, Brian; Lin, Wen; McElligott, Kristin; Domec, Jean‐Christophe; Gonzalez‐Benecke, Carlos; Jokela, Eric J.; Markewitz, Daniel; Meek, Cassandra; Miao, Guofang; McNulty, Steve G.; King, John S.; Samuelson, Lisa; Sun, Ge; Teskey, Robert; Vogel, Jason; Will, Rodney; Yang, Jinyan; Martin, Timothy A. 2021. Heterotrophic Respiration and the Divergence of Productivity and Carbon Sequestration. Geophysical Research Letters. 48(7) https://doi.org/10.1029/2020GL092366.
  • Keywords: Net primary productivity (NPP), net ecosystem production (NEP), Loblolly Pine
  • Posted Date: August 22, 2021
  • Modified Date: August 27, 2021
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