Impact of water table depth on forest soil methane turnover in laboratory soil cores deduced from natural abundance and tracer 13C stable isotope experiments.

Lancaster Environment Centre

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https://doi.org/10.1080/10256010600990765
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Keywords

Carbon-13, Forest, Methane, Soil, Turnover, Water table

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Impact of water table depth on forest soil methane turnover in laboratory soil cores deduced from natural abundance and tracer 13C stable isotope experiments. / McNamara, Niall P.; Chamberlain, Paul M.; Piearce, Trevor G. et al.
In: Isotopes in Environmental and Health Studies, Vol. 42, No. 4, 2006, p. 379-390.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Bibtex

@article{34221f4c00274c1594e90c8d4ce56716,

title = "Impact of water table depth on forest soil methane turnover in laboratory soil cores deduced from natural abundance and tracer 13C stable isotope experiments.",

abstract = "We investigated turnover of methane (CH4) in soils from a poorly drained UK forest. In situ, this forest exhibited a negligible soil-atmosphere CH4 flux, whereas adjacent grassland plots were sources of CH4. We hypothesised that the forest plots exhibited reduced anaerobic CH4 production through water-table draw down. Consequently, we exposed soil cores from under oak to high and low water-table conditions in the laboratory. Methane fluxes increased significantly in the high water-table (1925±1702 μg CH4 m-2 h-1) compared to the low one (-3.5±6.8 μg CH4 m-2 h-1). Natural abundance δ13C values of CH4 showed a strong depletion in high water-table cores (-56.7±2.9 ‰) compared to methane in ambient air (-46.0 ‰) indicative of methanogenic processes. The δ13C values of CH4 from low water-table cores (δ13C-46.8±0.2 ‰) was similar to ambient air and suggested little alteration of headspace CH4 by the soil microbial community. In order to assess the CH4 oxidizing activity of the two treatments conclusively, a 13CH4 spike was added to the cores and 13CO2 production was measured as the by-product of CH4 oxidation. 13CH4 oxidation rates were 57.5 (±12.7) and 0.5 (±0.1) μg CH4 m-2 h-1 for high and low water-tables, respectively. These data show that the lower water-table hydrology treatment impacted methanogenic processes without stimulating methanotrophy.",

keywords = "Carbon-13, Forest, Methane, Soil, Turnover, Water table",

author = "McNamara, {Niall P.} and Chamberlain, {Paul M.} and Piearce, {Trevor G.} and Darren Sleep and Black, {Helaina I.} and Reay, {David S.} and Phil Ineson",

year = "2006",

doi = "10.1080/10256010600990765",

language = "English",

volume = "42",

pages = "379--390",

journal = "Isotopes in Environmental and Health Studies",

issn = "1025-6016",

publisher = "Taylor and Francis Ltd.",

number = "4",

}

RIS

TY - JOUR

T1 - Impact of water table depth on forest soil methane turnover in laboratory soil cores deduced from natural abundance and tracer 13C stable isotope experiments.

AU - McNamara, Niall P.

AU - Chamberlain, Paul M.

AU - Piearce, Trevor G.

AU - Sleep, Darren

AU - Black, Helaina I.

AU - Reay, David S.

AU - Ineson, Phil

PY - 2006

Y1 - 2006

N2 - We investigated turnover of methane (CH4) in soils from a poorly drained UK forest. In situ, this forest exhibited a negligible soil-atmosphere CH4 flux, whereas adjacent grassland plots were sources of CH4. We hypothesised that the forest plots exhibited reduced anaerobic CH4 production through water-table draw down. Consequently, we exposed soil cores from under oak to high and low water-table conditions in the laboratory. Methane fluxes increased significantly in the high water-table (1925±1702 μg CH4 m-2 h-1) compared to the low one (-3.5±6.8 μg CH4 m-2 h-1). Natural abundance δ13C values of CH4 showed a strong depletion in high water-table cores (-56.7±2.9 ‰) compared to methane in ambient air (-46.0 ‰) indicative of methanogenic processes. The δ13C values of CH4 from low water-table cores (δ13C-46.8±0.2 ‰) was similar to ambient air and suggested little alteration of headspace CH4 by the soil microbial community. In order to assess the CH4 oxidizing activity of the two treatments conclusively, a 13CH4 spike was added to the cores and 13CO2 production was measured as the by-product of CH4 oxidation. 13CH4 oxidation rates were 57.5 (±12.7) and 0.5 (±0.1) μg CH4 m-2 h-1 for high and low water-tables, respectively. These data show that the lower water-table hydrology treatment impacted methanogenic processes without stimulating methanotrophy.

AB - We investigated turnover of methane (CH4) in soils from a poorly drained UK forest. In situ, this forest exhibited a negligible soil-atmosphere CH4 flux, whereas adjacent grassland plots were sources of CH4. We hypothesised that the forest plots exhibited reduced anaerobic CH4 production through water-table draw down. Consequently, we exposed soil cores from under oak to high and low water-table conditions in the laboratory. Methane fluxes increased significantly in the high water-table (1925±1702 μg CH4 m-2 h-1) compared to the low one (-3.5±6.8 μg CH4 m-2 h-1). Natural abundance δ13C values of CH4 showed a strong depletion in high water-table cores (-56.7±2.9 ‰) compared to methane in ambient air (-46.0 ‰) indicative of methanogenic processes. The δ13C values of CH4 from low water-table cores (δ13C-46.8±0.2 ‰) was similar to ambient air and suggested little alteration of headspace CH4 by the soil microbial community. In order to assess the CH4 oxidizing activity of the two treatments conclusively, a 13CH4 spike was added to the cores and 13CO2 production was measured as the by-product of CH4 oxidation. 13CH4 oxidation rates were 57.5 (±12.7) and 0.5 (±0.1) μg CH4 m-2 h-1 for high and low water-tables, respectively. These data show that the lower water-table hydrology treatment impacted methanogenic processes without stimulating methanotrophy.

KW - Carbon-13

KW - Forest

KW - Methane

KW - Soil

KW - Turnover

KW - Water table

U2 - 10.1080/10256010600990765

DO - 10.1080/10256010600990765

M3 - Journal article

VL - 42

SP - 379

EP - 390

JO - Isotopes in Environmental and Health Studies

JF - Isotopes in Environmental and Health Studies

SN - 1025-6016

IS - 4

ER -

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