Effects of simulated spring thaw of permafrost from mineral cryosol on CO2 emissions and atmospheric CH4 uptake

Brandon T. Stackhouse, Tatiana A. Vishnivetskaya, Alice Layton, Archana Chauhan, Susan Pfiffner, Nadia C. Mykytczuk, Rebecca Sanders, Lyle G. Whyte, Lars O. Hedin, Nabil Saad, Satish Chandra Babu Myneni, Tullis C. Onstott

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Previous studies investigating organic-rich tundra have reported that increasing biodegradation of Arctic tundra soil organic carbon (SOC) under warming climate regimes will cause increasing CO2 and CH4 emissions. Organic-poor, mineral cryosols, which comprise 87% of Arctic tundra, are not as well characterized. This study examined biogeochemical processes of 1 m long intact mineral cryosol cores (1-6% SOC) collected in the Canadian high Arctic. Vertical profiles of gaseous and aqueous chemistry and microbial composition were related to surface CO2 and CH4 fluxes during a simulated spring/summer thaw under light versus dark and in situ versus water saturated treatments. CO2 fluxes attained 0.8 ± 0.4 mmol CO2 m-2 h-1 for in situ treatments, of which 85 ± 11% was produced by aerobic SOC oxidation, consistent with field observations and metagenomic analyses indicating aerobic heterotrophs were the dominant phylotypes. The Q10 values of CO2 emissions ranged from 2 to 4 over the course of thawing. CH4 degassing occurred during initial thaw; however, all cores were CH4 sinks at atmospheric concentration CH4. Atmospheric CH4 uptake rates ranged from -126 ± 77 to -207 ± 7 nmol CH4 m-2 h-1 with CH4 consumed between 0 and 35 cm depth. Metagenomic and gas chemistry analyses revealed that high-affinity Type II methanotrophic sequence abundance and activity were highest between 0 and 35 cm depth. Microbial sulfate reduction dominated the anaerobic processes, outcompeting methanogenesis for H2 and acetate. Fluxes, microbial community composition, and biogeochemical rates indicate that mineral cryosols of Axel Heiberg Island act as net CO2 sources and atmospheric CH4 sinks during summertime thaw under both in situ and water saturated states.

Original languageEnglish (US)
Pages (from-to)1764-1784
Number of pages21
JournalJournal of Geophysical Research G: Biogeosciences
Volume120
Issue number9
DOIs
StatePublished - Sep 1 2015

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

Keywords

  • Axel Heiberg Island
  • carbon dioxide
  • methane
  • permafrost
  • polygonal terrain
  • thaw

Fingerprint Dive into the research topics of 'Effects of simulated spring thaw of permafrost from mineral cryosol on CO<sub>2</sub> emissions and atmospheric CH<sub>4</sub> uptake'. Together they form a unique fingerprint.

  • Cite this

    Stackhouse, B. T., Vishnivetskaya, T. A., Layton, A., Chauhan, A., Pfiffner, S., Mykytczuk, N. C., Sanders, R., Whyte, L. G., Hedin, L. O., Saad, N., Myneni, S. C. B., & Onstott, T. C. (2015). Effects of simulated spring thaw of permafrost from mineral cryosol on CO2 emissions and atmospheric CH4 uptake. Journal of Geophysical Research G: Biogeosciences, 120(9), 1764-1784. https://doi.org/10.1002/2015JG003004