TY - JOUR

T1 - Methane emissions from soils

T2 - synthesis and analysis of a large UK data set

AU - Levy, Peter E.

AU - Burden, Annette

AU - Cooper, Mark D. A.

AU - Dinsmore, Kerry J.

AU - Drewer, Julia

AU - Evans, Chris

AU - Fowler, David

AU - Gaiawyn, Jenny

AU - Gray, Alan

AU - Jones, Stephanie K.

AU - Jones, Timothy

AU - Mcnamara, Niall P.

AU - Mills, Robert

AU - Ostle, Nick

AU - Sheppard, Lucy J.

AU - Skiba, Ute

AU - Sowerby, Alwyn

AU - Ward, Susan E.

AU - Zielinski, Piotr

PY - 2012/5

Y1 - 2012/5

N2 - Nearly 5000 chamber measurements of CH4 flux were collated from 21 sites across the United Kingdom, covering a range of soil and vegetation types, to derive a parsimonious model that explains as much of the variability as possible, with the least input requirements. Mean fluxes ranged from -0.3 to 27.4 nmol CH4 m-2 s-1, with small emissions or low rates of net uptake in mineral soils (site means of -0.3 to 0.7 nmol m-2 s-1) and much larger emissions from organic soils (site means of -0.3 to 27.4 nmol m-2 s-1). Less than half of the observed variability in instantaneous fluxes could be explained by independent variables measured. The reasons for this include measurement error, stochastic processes and, probably most importantly, poor correspondence between the independent variables measured and the actual variables influencing the processes underlying methane production, transport and oxidation. When temporal variation was accounted for, and the fluxes averaged at larger spatial scales, simple models explained up to ca. 75% of the variance in CH4 fluxes. Soil carbon, peat depth, soil moisture and pH together provided the best sub-set of explanatory variables. However, where plant species composition data were available, this provided the highest explanatory power. Linear and nonlinear models generally fitted the data equally well, with the exception that soil moisture required a power transformation. To estimate the impact of changes in peatland water table on CH4 emissions in the United Kingdom, an emission factor of +0.4 g CH4 m-2 yr-1 per cm increase in water table height was derived from the data.

AB - Nearly 5000 chamber measurements of CH4 flux were collated from 21 sites across the United Kingdom, covering a range of soil and vegetation types, to derive a parsimonious model that explains as much of the variability as possible, with the least input requirements. Mean fluxes ranged from -0.3 to 27.4 nmol CH4 m-2 s-1, with small emissions or low rates of net uptake in mineral soils (site means of -0.3 to 0.7 nmol m-2 s-1) and much larger emissions from organic soils (site means of -0.3 to 27.4 nmol m-2 s-1). Less than half of the observed variability in instantaneous fluxes could be explained by independent variables measured. The reasons for this include measurement error, stochastic processes and, probably most importantly, poor correspondence between the independent variables measured and the actual variables influencing the processes underlying methane production, transport and oxidation. When temporal variation was accounted for, and the fluxes averaged at larger spatial scales, simple models explained up to ca. 75% of the variance in CH4 fluxes. Soil carbon, peat depth, soil moisture and pH together provided the best sub-set of explanatory variables. However, where plant species composition data were available, this provided the highest explanatory power. Linear and nonlinear models generally fitted the data equally well, with the exception that soil moisture required a power transformation. To estimate the impact of changes in peatland water table on CH4 emissions in the United Kingdom, an emission factor of +0.4 g CH4 m-2 yr-1 per cm increase in water table height was derived from the data.

KW - CH4

KW - data synthesis

KW - greenhouse gases

KW - meta-analysis

KW - methane

KW - methanogenesis

KW - static chamber

KW - GREENHOUSE-GAS FLUXES

KW - NORTHERN PEATLANDS

KW - DISCONTINUOUS PERMAFROST

KW - ATMOSPHERIC CO2

KW - SPHAGNUM PEAT

KW - CARBON

KW - WETLAND

KW - DYNAMICS

KW - ECOSYSTEMS

KW - RESPONSES

U2 - 10.1111/j.1365-2486.2011.02616.x

DO - 10.1111/j.1365-2486.2011.02616.x

M3 - Journal article

VL - 18

SP - 1657

EP - 1669

JO - Global Change Biology

JF - Global Change Biology

SN - 1354-1013

IS - 5

ER -