Non-linear response of carbon dioxide and methane emissions to oxygen availability in a drained histosol

McNicol, Gavin; Silver, Whendee L.

doi:10.1007/s10533-015-0075-6

Cited by 18 publications

(12 citation statements)

References 38 publications

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“…This close correlation can be explained by the aerobic CH 4 oxidation in the water. Our result was supported by the previous finding that a high DO concentration in the water results in low CH 4 emission (Rõõm et al, 2014;McNicol and Silver, 2015;Yang et al, 2015).…”

Section: Timescale Dependence Of Wind Substrate Availability and Tesupporting

confidence: 91%

Timescale dependence of environmental controls on methane efflux from Poyang Hu, China

Liu

et al. 2017

Biogeosciences

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Abstract. Lakes are an important natural source of CH4 to the atmosphere. However, the multi-seasonal CH4 efflux from lakes has been rarely studied. In this study, the CH4 efflux from Poyang Hu, the largest freshwater lake in China, was measured monthly over a 4-year period by using the floating-chamber technique. The mean annual CH4 efflux throughout the 4 years was 0.54 mmol m−2 day−1, ranging from 0.47 to 0.60 mmol m−2 day−1. The CH4 efflux had a high seasonal variation with an average summer (June to August) efflux of 1.34 mmol m−2 day−1 and winter (December to February) efflux of merely 0.18 mmol m−2 day−1. The efflux showed no apparent diel pattern, although most of the peak effluxes appeared in the late morning, from 10:00 to 12:00 CST (GMT + 8). Multivariate stepwise regression on a seasonal scale showed that environmental factors, such as sediment temperature, sediment total nitrogen content, dissolved oxygen, and total phosphorus content in the water, mainly regulated the CH4 efflux. However, the CH4 efflux only showed a strong positive linear correlation with wind speed within 1 day on a bihourly scale in the multivariate regression analyses but almost no correlation with wind speed on diurnal and seasonal scales.

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Section: Timescale Dependence Of Wind Substrate Availability and Tesupporting

confidence: 91%

Timescale dependence of environmental controls on methane efflux from Poyang Hu, China

Liu

et al. 2017

Biogeosciences

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“…Moreover, the recent discovery of the widespread occurrence of AOM in soils suggests that methanogenesis could be underestimated under anoxic conditions (Blazewicz et al, ; Gauthier et al, ; Gupta et al, ; Smemo & Yavitt, , ). Conventional assays for CH 4 oxidation potential, conducted under oxic conditions, can also lead to poor estimates of in situ methanotrophy for multiple reasons: these approaches do not account for AOM (Blazewicz et al, ; Smemo & Yavitt, ); methanogenesis can occur in reduced microsites in oxic soils (Teh et al, ; von Fischer & Hedin, ; von Fischer et al, ); CH 4 oxidation may be strongly dependent on microsite methanogenesis (Yang & Silver, ); and CH 4 dynamics may be non‐linearly sensitive to changes in O 2 concentrations (McNicol & Silver, ). Moreover, these assays are conducted over widely varying time scales—from hours to days to weeks—with the longer incubations run until CH 4 production or oxidation are stimulated, therefore likely allowing microbial growth that confounds the interpretation of the measured rates.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Classical Versus an Emerging Conceptual Model of Peatland Methane Dynamics

Yang

McNicol

Teh

et al. 2017

Global Biogeochemical Cycles

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Methane (CH4) is a potent greenhouse gas that is both produced and consumed in soils by microbially mediated processes sensitive to soil redox. We evaluated the classical conceptual model of peatland CH4 dynamics—in which the water table position determines the vertical distribution of methanogenesis and methanotrophy—versus an emerging model in which methanogenesis and methanotrophy can both occur throughout the soil profile due to spatially heterogeneous redox and anaerobic CH4 oxidation. We simultaneously measured gross CH4 production and oxidation in situ across a microtopographical gradient in a drained temperate peatland and ex situ along the soil profile, giving us novel insight into the component fluxes of landscape‐level net CH4 fluxes. Net CH4 fluxes varied among landforms (p < 0.001), ranging from 180.3 ± 81.2 mg C m−2 d−1 in drainage ditches to −0.7 ± 1.2 mg C m−2 d−1 in the highest landform. Contrary to prediction by the classical conceptual model, variability in methanogenesis alone drove the landscape‐level net CH4 flux patterns. Consistent with the emerging model, freshly collected soils from above the water table produced CH4 within anaerobic microsites. Even in soil from beneath the water table, gross CH4 production was best predicted by the methanogenic fraction of carbon mineralization, an index of highly reducing microsites. We measured low rates of anaerobic CH4 oxidation, which may have been limited by relatively low in situ CH4 concentrations in the hummock/hollow soil profile. Our study revealed complex CH4 dynamics better represented by the emerging heterogeneous conceptual model than the classical model based on redox strata.

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“…Organic matter stocks in peatlands are several times higher than in other ecosystems despite lower rates of primary production, indicating that net accumulation is primarily due to limited decomposition [Schlesinger and Bernhardt, 2013;Thormann et al, 1999]. Decomposition is likely incomplete due to a variety of factors including low temperatures [Lafleur et al, 2005], restricted oxygen exposure [Belyea and Clymo, 2001;McNicol and Silver, 2015;Philben et al, 2014b], and the poor litter quality of Sphagnum, the dominant moss in many peatland plant communities [Moore et al, 2007]. However, the relative importance of these factors remains poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

Philben

Holmquist

MacDonald

et al. 2015

Global Biogeochemical Cycles

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The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an increasing contribution of vascular plants to the vegetation.

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Non-linear response of carbon dioxide and methane emissions to oxygen availability in a drained histosol

Cited by 18 publications

References 38 publications

Timescale dependence of environmental controls on methane efflux from Poyang Hu, China

Timescale dependence of environmental controls on methane efflux from Poyang Hu, China

Evaluating the Classical Versus an Emerging Conceptual Model of Peatland Methane Dynamics

Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

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