Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin

Paul H. Glaser, Donald I. Siegel, Jeffrey P. Chanton, Andrew S. Reeve, Donald O. Rosenberry, J. Elizabeth Corbett, Soumitri Dasgupta, Zeno Levy

Research output: Contribution to journalArticle

Abstract

Northern peatlands are an important source for greenhouse gases, but their capacity to produce methane remains uncertain under changing climatic conditions. We therefore analyzed a 43year time series of the pore-water chemistry to determine if long-term shifts in precipitation altered the vertical transport of solutes within a large peat basin in northern Minnesota. These data suggest that rates of methane production can be finely tuned to multidecadal shifts in precipitation that drive the vertical penetration of labile carbon substrates within the Glacial Lake Agassiz Peatlands. Tritium and cation profiles demonstrate that only the upper meter of these peat deposits was flushed by downwardly moving recharge from 1965 to 1983 during a Transitional Dry-to-Moist Period. However, a shift to a moister climate after 1984 drove surface waters much deeper, largely flushing the pore waters of all bogs and fens to depths of 2m. Labile carbon compounds were transported downward from the rhizosphere to the basal peat at this time producing a substantial enrichment of methane in Δ14C with respect to the solid-phase peat from 1991 to 2008. These data indicate that labile carbon substrates can fuel deep production zones of methanogenesis that more than doubled in thickness across this large peat basin after 1984. Moreover, the entire peat profile apparently has the capacity to produce methane from labile carbon substrates depending on climate-driven modes of solute transport. Future changes in precipitation may therefore play a central role in determining the source strength of peatlands in the global methane cycle.

Original languageEnglish (US)
JournalGlobal Biogeochemical Cycles
DOIs
StateAccepted/In press - 2016

Fingerprint

peat
Pair Bond
methane
carbon
peatland
substrate
basin
Substrates
solute transport
porewater
climate
Solute transport
Glacial Lake Agassiz
methanogenesis
tritium
fen
bog
flushing
water chemistry
rhizosphere

Keywords

  • Carbon cycling
  • Climatic change
  • Hydrogeology
  • Methane production
  • Peatlands

ASJC Scopus subject areas

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

Cite this

Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin. / Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno.

In: Global Biogeochemical Cycles, 2016.

Research output: Contribution to journalArticle

Glaser, Paul H.; Siegel, Donald I.; Chanton, Jeffrey P.; Reeve, Andrew S.; Rosenberry, Donald O.; Corbett, J. Elizabeth; Dasgupta, Soumitri; Levy, Zeno / Climatic drivers for multidecadal shifts in solute transport and methane production zones within a large peat basin.

In: Global Biogeochemical Cycles, 2016.

Research output: Contribution to journalArticle

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