The Importance of Spring Mixing in Evaluating Carbon Dioxide and Methane Flux From a Small North‐temperate Lake in Wisconsin, USA

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal EcosystemAtmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m2 during 1994 and 135 g C·m2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m2 during 1994 and 270 g C·m2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of 0.5 mg CH4·m2·day1 for OBS and 2.8 mg CH4·m2·day1 for fen sites, suggest that spruce areas are net annual sinks of about 0.12 g CH4·m2, whereas fen areas generate net annual emissions on the order of 0.30.85 g CH4·m2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

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Post-fire carbon dioxide emissions from a peatland undergoing restoration

10.5194/egusphere-egu21-12193 ◽

2021 ◽

Author(s):

Rebekka Artz ◽

Mhairi Coyle ◽

Pete Gilbert ◽

Roxane Andersen ◽

Adrian Bass

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Emissions ◽

Methane Flux ◽

Slope Aspect ◽

Unesco World Heritage ◽

Greenhouse Gas Flux ◽

Significant Damage ◽

Blanket Bog ◽

One Year ◽

The Uk

In May 2019, a major wildfire event affected >60 km2 within the 4000 km2 Flow Country in Northern Scotland, UK, a flagship blanket bog peatland that is being considered for UNESCO World Heritage Status. While the fire itself created significant damage, it also led to an extraordinary and unique opportunity to compare burned and unburned landscape scale greenhouse gas flux and surface energy dynamics using sites that, crucially, have otherwise identical biophysical characteristics (slope, aspect, peat depth) and land management histories. Since September 2019, carbon dioxide and methane flux data have been collected alongside other micrometeorological variables. Due to the COVID-19 lockdown in the UK, the team had severe difficulties in maintaining the equipment and hence, only partial and preliminary data will be reported here to showcase the findings from this project to date. The data obtained so far suggest a post-fire reduction in net CO2 emissions for a period of one year since the beginning of our monitoring campaign.

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Methane and carbon dioxide dynamics affected by water-level fluctuations in a shallow lake: Implications for wetland restoration

10.5194/egusphere-egu2020-6437 ◽

2020 ◽

Author(s):

Xiaomin Yuan ◽

Qiang Liu

Keyword(s):

Carbon Dioxide ◽

Water Level ◽

Wetland Restoration ◽

Shallow Lake ◽

Carbon Emission ◽

Methane Flux ◽

Water Level Fluctuation ◽

Level Fluctuation ◽

Dndc Model ◽

Fluctuation Frequency

Shallow lake was characterized by distinct hydrology, biochemistry and ecology that influence the carbon balance. This study explored methane and carbon emission responses to water level fluctuation in shallow lake, and also addressed its legacy for wetland restoration. This study used the process-based biogeochemical model, denitrification-decomposition (DNDC) model to simulate the alteration of methane and carbon emission with water level fluctuation in the Baiyangdian Lake (BYD Lake). The results showed: (i) compared with the observed carbon flux, the DNDC model can presented a suitable results in capturing the dynamics of methane and carbon dioxide, and the daily rate of carbon dioxide and methane emission showed sensitive to water fluctuation when it ranged from -10 cm to 10 cm; (ii) for the carbon dioxide, the annual flux showed a decline trend when the duration prolonged from 10 days to 40 days, and then an increasing trend while the duration prolonged to 90 days furtherly, with a lowest flux when the duration is 40 days, while for the methane, annual emission increased with inundation lasting time and the flux changing from -2.27 kg C/ha/y to 1.57 kg C/ha/y; and (iii) The flux of carbon dioxide and methane increased when water level fluctuation frequency increased, for a certain water level fluctuation frequency, carbon dioxide flux is lowest in January and February, and methane flux is negative from December to March of the following year. All of these results indicated that water level fluctuation (e.g., magnitude, duration and frequency) affected the carbon dioxide and methane flux, which will help to reduce the emission of carbon dioxide and methane by regulating ecological water transfer.Keywords: shallow lake, carbon emission; DNDC; water level fluctuationAcknowledgmentsThis study was supported by the National Key R&D Program of China (No. 2018ZX07110001, No. 2017YFC0404505) and the National Natural Science Foundation of China (No. 51579008).

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Eddy covariance measurements of the net turbulent methane flux in the city centre – results of 2 years campaign in Łódź, Poland

10.5194/acp-2015-979 ◽

2016 ◽

Author(s):

W. Pawlak ◽

K. Fortuniak

Keyword(s):

Carbon Dioxide ◽

Eddy Covariance ◽

Vertical Component ◽

Ground Level ◽

Methane Flux ◽

City Centre ◽

Carbon Dioxide Fluxes ◽

Methane Fluxes ◽

Eddy Covariance Measurements ◽

The City

Abstract. In the period between July 2013 and August 2015, continuous measurements of turbulent methane exchange between an urbanised area and the atmosphere were carried out in Łódź. Such long, continuous measurement series of turbulent methane exchange between the city and the atmosphere are still a rarity. The measurement station was located in the centre of the city, where fluxes of energy (sensible and latent heat) and fluxes of mass (carbon dioxide) have been continuously measured since 2000 and 2007, respectively. In the immediate vicinity of the measurement station there are potential sources of methane, such as streets with vehicle traffic or dense sewerage and natural gas networks. To determine the fluxes, the eddy covariance technique was used; the measurement station was equipped with instruments for recording fluctuations in the vertical component of the wind speed (an ultrasonic 3D anemometer, RM Young 81000, RM Young, USA) as well as the concentration of methane in the air (an open path Li 7700 CH4 Analyser, Li-cor, USA). The devices were mounted on a mast at a height of 37 metres above ground level and, on average, 20 metres over the roofs of the surrounding buildings. The results were therefore averaged for an area with a diameter of approximately 1 kilometre. Our aim was to investigate the temporal variability of the turbulent exchange of methane in the city-atmosphere system. The results show in the first place that positive methane fluxes (turbulent gas transport from the surface to the atmosphere) definitely dominate compared with negative fluxes. This indicates that the study area of the centre of Łódź is a net source of methane to the troposphere. The measurements also indicated the existence of a clear annual rhythm of the turbulent flux of methane in the centre of Łódź (on average, the values observed in winter amounted to ~40–60 nmol m−2 s−1 and were significantly larger than in summer). The daily variability of the flux of CH4 (FCH4) is faintly visible throughout the year. The studied area of the centre of Łódź is also characterised by a cycle of methane exchange – the values measured on working days were higher by 6.6 % (winter) to 5.6 % (summer) than those observed at weekends. The largest monthly exchange was characteristic of winter months (from 2.0 to 2.7 g m−2 month−1) and the lowest occurred in summer (from 0.8 to 1.0 g m−2 month−1). The mean daily patterns of FCH4 in consecutive months were used to determine the cumulative annual exchange. In 2014, the centre of Łódź emitted a net quantity of almost 18 g m−2. Furthermore, the study analyses the covariability of methane and carbon dioxide fluxes.

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Methane in Australian agriculture: current emissions, sources and sinks, and potential mitigation strategies

Crop and Pasture Science ◽

10.1071/cp14116 ◽

2015 ◽

Vol 66 (1) ◽

pp. 1 ◽

Cited By ~ 4

Author(s):

Damien Finn ◽

Ram Dalal ◽

Athol Klieve

Keyword(s):

Climate Change ◽

Carbon Dioxide ◽

Plant Biomass ◽

Methane Flux ◽

Methane Emissions ◽

Mitigation Strategies ◽

Extreme Weather Events ◽

Future Research ◽

Sources And Sinks ◽

Climate Change Drivers

Methane is a potent greenhouse gas with a global warming potential ~28 times that of carbon dioxide. Consequently, sources and sinks that influence the concentration of methane in the atmosphere are of great interest. In Australia, agriculture is the primary source of anthropogenic methane emissions (60.4% of national emissions, or 3 260 kt–1 methane year–1, between 1990 and 2011), and cropping and grazing soils represent Australia’s largest potential terrestrial methane sink. As of 2011, the expansion of agricultural soils, which are ~70% less efficient at consuming methane than undisturbed soils, to 59% of Australia’s land mass (456 Mha) and increasing livestock densities in northern Australia suggest negative implications for national methane flux. Plant biomass burning does not appear to have long-term negative effects on methane flux unless soils are converted for agricultural purposes. Rice cultivation contributes marginally to national methane emissions and this fluctuates depending on water availability. Significant available research into biological, geochemical and agronomic factors has been pertinent for developing effective methane mitigation strategies. We discuss methane-flux feedback mechanisms in relation to climate change drivers such as temperature, atmospheric carbon dioxide and methane concentrations, precipitation and extreme weather events. Future research should focus on quantifying the role of Australian cropping and grazing soils as methane sinks in the national methane budget, linking biodiversity and activity of methane-cycling microbes to environmental factors, and quantifying how a combination of climate change drivers will affect total methane flux in these systems.

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The seasonal cycle of the greenhouse gas balance of a continental tundra site in the Indigirka lowlands, NE Siberia

Biogeosciences Discussions ◽

10.5194/bgd-4-2329-2007 ◽

2007 ◽

Vol 4 (4) ◽

pp. 2329-2384 ◽

Cited By ~ 3

Author(s):

M. K. van der Molen ◽

J. C. van Huissteden ◽

F. J. Parmentier ◽

A. M. R. Petrescu ◽

A. J. Dolman ◽

...

Keyword(s):

Carbon Dioxide ◽

Soil Temperature ◽

Greenhouse Gas ◽

Methane Flux ◽

Light Limitation ◽

Greenhouse Gas Balance ◽

Area Index ◽

North East ◽

Methane Fluxes ◽

Gas Balance

Abstract. Carbon dioxide and methane fluxes were measured at a tundra site near Chokurdakh, in the lowlands of the Indigirka river in north-east Siberia. This site is one of the few stations on Russian tundra and it is different from most other tundra flux stations in its continentality. A suite of methods was applied to determine the fluxes of NEE, GPP, Reco and methane, including eddy covariance, chambers and leaf cuvettes. Net carbon dioxide fluxes were unusually high, compared with other tundra sites, with NEE=–92 g C m−2 yr−1, which is composed of an Reco=+141 g C m−2 yr−1 and GPP=–232 g C m−2 yr−1. This large carbon dioxide sink may be explained by the continental climate, that is reflected in low winter soil temperatures (–14°C), reducing the respiration rates, and short, relatively warm summers, stimulating high photosynthesis rates. Interannual variability in GPP was dominated by the frequency of light limitation (Rg <200 W m−2), whereas Reco depends most directly on soil temperature and time in the growing season, which serves as a proxy of the combined effects of active layer depth, leaf area index, soil moisture and substrate availability. The methane flux, in units of global warming potential, was +28 g C-CO2e m−2 yr−1, so that the greenhouse gas balance was –64 g C-CO2e m−2 yr−1. Methane fluxes depended only slightly on soil temperature and were highly sensitive to hydrological conditions and vegetation composition.

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Effects of Wind and Buoyancy on Carbon Dioxide Distribution and Air-Water Flux of a Stratified Temperate Lake

Journal of Geophysical Research Biogeosciences ◽

10.1029/2017jg004209 ◽

2018 ◽

Vol 123 (8) ◽

pp. 2305-2322 ◽

Cited By ~ 9

Author(s):

Matthew J. Czikowsky ◽

Sally MacIntyre ◽

Edmund W. Tedford ◽

Javier Vidal ◽

Scott D. Miller

Keyword(s):

Carbon Dioxide ◽

Water Flux ◽

Temperate Lake

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Carbon Dioxide and Methane Flux in a Dynamic Arctic Tundra Landscape: Decadal‐Scale Impacts of Ice Wedge Degradation and Stabilization

Geophysical Research Letters ◽

10.1029/2020gl089894 ◽

2020 ◽

Vol 47 (22) ◽

Author(s):

K. P. Wickland ◽

M. T. Jorgenson ◽

J. C. Koch ◽

M. Kanevskiy ◽

R. G. Striegl

Keyword(s):

Carbon Dioxide ◽

Methane Flux ◽

Arctic Tundra ◽

Decadal Scale ◽

Ice Wedge

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THE INFLUENCE OF WATER TABLE LEVELS ON METHANE AND CARBON DIOXIDE EMISSIONS FROM PEATLAND SOILS

Canadian Journal of Soil Science ◽

10.4141/cjss89-004 ◽

1989 ◽

Vol 69 (1) ◽

pp. 33-38 ◽

Cited By ~ 293

Author(s):

T. R. MOORE ◽

R. KNOWLES

Keyword(s):

Carbon Dioxide ◽

Water Table ◽

Carbon Dioxide Emissions ◽

Methane Flux ◽

Organic Soils ◽

Molar Ratios ◽

Microbial Characteristics ◽

Influence Of Water ◽

Peat Surface ◽

Logarithmic Relationship

The evolution of carbon dioxide and methane was measured from laboratory columns packed with surface (0–30 cm) materials representing a fen, a bog and a swamp and with varying water tables and treated with water containing 10 mg L−1 dissolved organic carbon. Carbon dioxide evolution increased in a linear relationship as the water table was lowered, ranging from 0.3–0.5 g CO2 m−2 d−1 to 6.6–9.4 g CO2 m−2 d−1 for the water table at 10 cm above and 70 cm below the peat surface, respectively. Methane evolution decreased in a logarithmic relationship as the water table was lowered. The fen showed the highest rates of methane flux (28 mg CH4 m−2 d−1 when inundated) and the bog the lowest (0.7 mg CH4 m−2 d−1 when inundated). These differences appeared to be related to the acidity of the soils and their microbial characteristics. Molar ratios of carbon dioxide:methane evolution increased from 4 to 173 under inundated conditions to > 2500 when the water table was at a depth of 70 cm. Key words: Methane, carbon dioxide, water table, organic soils, peatlands

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