An accounting of C-based trace gas release during abiotic plant litter degradation

Hanna Lee, Thom Rahn, Heather Throop

Research output: Contribution to journalArticle

66 Scopus citations

Abstract

Recent studies showed that photochemical breakdown (photodegradation) of plant material accounts for a substantial portion of litter decomposition and subsequent trace gas release in ecosystems under high radiative load and low precipitation. In the absence of solar radiation, thermal degradation may also cause trace gas release at temperatures below the ignition point. These observations suggest that the abiotic processes of photodegradation and thermal degradation of plant litter may be important in understanding global trace gas budgets. In a laboratory incubation study, we performed a simultaneous carbon (C) accounting of CO 2, CO, and CH 4 produced as a byproduct of photodegradation and thermal degradation of six different plant litter types that varied in chemical composition. The patterns of trace gas release during photodegradation and thermal degradation differed considerably across the six plant materials, suggesting that chemical composition of litter may influence the rates of abiotic degradation. There was a strong positive correlation between the rates of trace gas release during photodegradation and temperature. A significant portion of trace gases were produced during low temperature (< 100 °C) thermal degradation of litter in the absence of solar radiation, which was also positively correlated to temperature. In addition, both thermal degradation and photodegradation occurred in the absence of O 2. This indicates that the mechanism formerly accepted as photo-oxidation may only be one of several photodegradation processes. We speculate that the direct breakdown of chemical groups such as carboxyl, carbonyl, and methoxyl groups may result in CO 2, CO, and CH 4 release. We suggest that the combined processes of thermal and photodegradation of litter may be a previously under accounted source of C-based trace gases from terrestrial systems.

Original languageEnglish (US)
Pages (from-to)1185-1195
Number of pages11
JournalGlobal change biology
Volume18
Issue number3
DOIs
StatePublished - Mar 2012

Keywords

  • CH4
  • CO
  • CO
  • Litter decomposition
  • Photodegradation
  • Thermal degradation

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

Fingerprint Dive into the research topics of 'An accounting of C-based trace gas release during abiotic plant litter degradation'. Together they form a unique fingerprint.

  • Cite this