CH[sub 4] production via CO[sub 2] reduction in a temperate bog: A source of [sup 13]C-depleted CH[sub 4]

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90393-W· OSTI ID:6955165

Lansdown, J M; Quay, P D; King, S L ^[1]

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1. Univ. of Washington, Seattle (United States)

The flux and [delta][sup 13]C of CH[sub 4] released from an acidic peat bog (pH = 3.5), located in the foothills of the Cascade Range in Washington state, USA, were measured over two annual cycles. The CH[sub 4] flux ranged from 1-380 mg CH[sub 4]-C/m[sup 2]d, with an annual average of 73-mg CH[sub 4]-C/m[sup 2]d, and correlated with soil temperature. Ebullition accounted for 89% of the methane flux. The average [delta][sup 13]C of the CH[sub 4] flux was [minus]74 [plus minus] 5 [per thousand], with no relationship between the [delta][sup 13]C and flux of CH[sub 4]. The [delta][sup 13]C of CH[sub 4] and CO[sub 2] in bubbles disturbed from the peat soil was [minus]73 [plus minus] 4 and [minus]2 [plus minus] 3 [per thousand], respectively. The [delta]D of CH[sub 4] in bubbles was [minus]308 [plus minus] 35 [per thousand], and the [delta]D of soil water was [minus]65 [plus minus] 3 [per thousand]. Measurements of the rate of aceticlastic methanogenesis and CO[sub 2] reduction in peat soil, using [sup 14]C-labeled acetate and sodium bicarbonate, show that acetate was not an important CH[sub 4] precursor and that CO[sub 2] reduction could account for all of the CH[sub 4] production. The in situ kinetic isotope effect for CO[sub 2] reduction ([alpha][sub r]), calculated using the [delta][sup 13]C of soil water CO[sub 2] and the CH[sub 4] flux, was 0.932 [plus minus] 0.007. The [delta][sup 13]C of CH[sub 4] and CO[sub 2] coexisting in soil waters provides an isotopic tracer of CH[sub 4] production via CO[sub 2] reduction.

• OSTI ID: 6955165
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:9; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
290301 -- Energy Planning & Policy-- Environment
Health
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54 ENVIRONMENTAL SCIENCES
540110*
AIR
AIR POLLUTION MONITORING
ALKANES
AQUATIC ECOSYSTEMS
ATMOSPHERIC CHEMISTRY
CARBON 13
CARBON COMPOUNDS
CARBON CYCLE
CARBON DIOXIDE
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DEGASSING
DEVELOPED COUNTRIES
ECOLOGICAL CONCENTRATION
ECOSYSTEMS
ENERGY SOURCES
EVEN-ODD NUCLEI
FEDERAL REGION X
FLUIDS
FOSSIL FUELS
FUELS
GASES
HYDROCARBONS
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MATTER
METHANE
MONITORING
NORTH AMERICA
NUCLEI
ORGANIC COMPOUNDS
ORGANIC MATTER
OXIDES
OXYGEN COMPOUNDS
PEAT
REDUCTION
STABLE ISOTOPES
SURFACE AIR
SYNTHESIS
USA
VARIATIONS
WASHINGTON
WETLANDS