HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

Abstract. Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we composed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation, and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2, and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure and results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and demonstrate that HIMMELI outputs realistic fluxes by comparing modeled and measured fluxes at two peatland sites. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that (1) the model is flexible and robust and thus suitable for different environments; (2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; (3) the sensitivity of the total CH4 emission to other input variables is mainly mediated via the concentrations of dissolved gases, in particular, the O2 concentrations that affect the CH4 production and oxidation rates; (4) with given input respiration, the peat column description does not significantly affect the simulated CH4 emissions in this model version.

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HIMMELI v1.0: HelsinkI Model of MEthane buiLd-up and emIssion for peatlands

10.5194/gmd-2017-52 ◽

2017 ◽

Author(s):

Maarit Raivonen ◽

Sampo Smolander ◽

Leif Backman ◽

Jouni Susiluoto ◽

Tuula Aalto ◽

...

Keyword(s):

Carbon Cycle ◽

Flux Measurement ◽

Environmental Drivers ◽

Co2 Production ◽

Area Index ◽

Carbon Cycle Model ◽

Ch4 Emissions ◽

Oxidation Rates ◽

Ch4 Production ◽

Carbon Dioxide Co2

Abstract. Wetlands are one of the most significant natural sources of methane (CH4) to the atmosphere. They emit CH4 because decomposition of soil organic matter in waterlogged anoxic conditions produces CH4, in addition to carbon dioxide (CO2). Production of CH4 and how much of it escapes to the atmosphere depend on a multitude of environmental drivers. Models simulating the processes leading to CH4 emissions are thus needed for upscaling observations to estimate present CH4 emissions and for producing scenarios of future atmospheric CH4 concentrations. Aiming at a CH4 model that can be added to models describing peatland carbon cycling, we developed a model called HIMMELI that describes CH4 build-up in and emissions from peatland soils. It is not a full peatland carbon cycle model but it requires the rate of anoxic soil respiration as input. Driven by soil temperature, leaf area index (LAI) of aerenchymatous peatland vegetation and water table depth (WTD), it simulates the concentrations and transport of CH4, CO2 and oxygen (O2) in a layered one-dimensional peat column. Here, we present the HIMMELI model structure, results of tests on the model sensitivity to the input data and to the description of the peat column (peat depth and layer thickness), and an intercomparison of the modelled and measured CH4 fluxes at Siikaneva, a peatland flux measurement site in Southern Finland. As HIMMELI describes only the CH4-related processes, not the full carbon cycle, our analysis revealed mechanisms and dependencies that may remain hidden when testing CH4 models connected to complete peatland carbon models, which is usually the case. Our results indicated that 1) the model is flexible and robust and thus suitable for different environments; 2) the simulated CH4 emissions largely depend on the prescribed rate of anoxic respiration; 3) the sensitivity of the total CH4 emission to other input variables, LAI and WTD, is mainly mediated via the O2 concentrations that affect the CH4 production and oxidation rates; 4) with given input respiration, the peat column description does not affect significantly the simulated CH4 emissions.

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Comment on "Carbon farming in hot, dry coastal areas: an option for climate change mitigation" by Becker et al. (2013)

Earth System Dynamics Discussions ◽

10.5194/esdd-4-869-2013 ◽

2013 ◽

Vol 4 (2) ◽

pp. 869-873

Author(s):

M. Heimann

Keyword(s):

Carbon Cycle ◽

Carbon Sink ◽

Co2 Concentration ◽

Global Carbon Cycle ◽

Atmospheric Co2 ◽

Reference Scenario ◽

Carbon Cycle Model ◽

Terrestrial Carbon Sink ◽

Carbon Dioxide Co2 ◽

Global Carbon

Abstract. Becker et al. (2013) argue that an afforestation of 0.73 109 ha with Jatropha curcas plants would generate an additional terrestrial carbon sink of 4.3 PgC yr−1, enough to stabilise the atmospheric mixing ratio of carbon dioxide (CO2) at current levels. However, this is not consistent with the dynamics of the global carbon cycle. Using a well established global carbon cycle model, the effect of adding such a hypothetical sink leads to a reduction of atmospheric CO2 levels in the year 2030 by 25 ppm compared to a reference scenario. However, the stabilisation of the atmospheric CO2 concentration requires a much larger additional sink or corresponding reduction of anthropogenic emissions.

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Correlations of methane and carbon dioxide concentrations from feedlot cattle as a predictor of methane emissions

Animal Production Science ◽

10.1071/an14550 ◽

2016 ◽

Vol 56 (1) ◽

pp. 108 ◽

Cited By ~ 6

Author(s):

Mei Bai ◽

David W. T. Griffith ◽

Frances A. Phillips ◽

Travis Naylor ◽

Stephanie K. Muir ◽

...

Keyword(s):

Carbon Dioxide ◽

Concentration Ratio ◽

Co2 Concentration ◽

Feedlot Cattle ◽

Mitigation Strategies ◽

Co2 Production ◽

Ch4 Emissions ◽

Carbon Dioxide Concentrations ◽

Carbon Dioxide Co2 ◽

Animal Diet

Accurate measurements of methane (CH4) emissions from feedlot cattle are required for verifying greenhouse gas (GHG) accounting and mitigation strategies. We investigate a new method for estimating CH4 emissions by examining the correlation between CH4 and carbon dioxide (CO2) concentrations from two beef cattle feedlots in Australia representing southern temperate and northern subtropical locations. Concentrations of CH4 and CO2 were measured at the two feedlots during summer and winter, using open-path Fourier transform infrared spectroscopy. There was a strong correlation for the concentrations above background of CH4 and CO2 with concentration ratios of 0.008 to 0.044 ppm/ppm (R2 >0.90). The CH4/CO2 concentration ratio varied with animal diet and ambient temperature. The CH4/CO2 concentration ratio provides an alternative method to estimate CH4 emissions from feedlots when combined with CO2 production derived from metabolisable energy or heat production.

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Greenhouse gas production in degrading ice-rich permafrost deposits in northeast Siberia

10.5194/bg-2018-225 ◽

2018 ◽

Author(s):

Josefine Walz ◽

Christian Knoblauch ◽

Ronja Tigges ◽

Thomas Opel ◽

Lutz Schirrmeister ◽

...

Keyword(s):

Greenhouse Gases ◽

Greenhouse Gas ◽

Late Glacial ◽

Gas Production ◽

Depositional Environments ◽

Co2 Production ◽

Glacial Deposits ◽

Ch4 Production ◽

Carbon Dioxide Co2

Abstract. Permafrost deposits have been a sink for atmospheric carbon for millennia. Thaw-erosional processes, however, can lead to rapid degradation of ice-rich permafrost and the release of substantial amounts of organic carbon (OC). The amount of the OC stored in these deposits and their potential to be microbially decomposed to the greenhouse gases carbon dioxide (CO2) and methane (CH4) depends on climatic and environmental conditions during deposition and the decomposition history before incorporation into the permafrost. Here, we examine potential greenhouse gas production in degrading ice-rich permafrost deposits from three locations in the northeast Siberian Laptev Sea region. The deposits span a period of about 55 kyr and include deposits from the last glacial and Holocene interglacial periods. Samples from all three locations were aerobically and anaerobically incubated for 134 days at 4 °C. Greenhouse gas production was generally higher in glacial than Holocene deposits. In permafrost deposits from the Holocene and the late glacial transition, only 0.1–4.0 % of the initially available OC could be decomposed to CO2, while 0.2–6.1 % could be decomposed in glacial deposits. Within the glacial deposits from the Kargin interstadial period (Marine Isotope Stage 3), local depositional environments, especially soil moisture, also affected the preservation of OC. Sediments deposited under wet conditions contained more labile OC and thus produced more greenhouse gases than sediments deposited under drier conditions. To assess the long-term production potentials, deposits from two locations were incubated for a total of 785 days. However, more than 50 % of the aerobically produced and more than 80 % of anaerobically produced CO2 after 785 days of incubation were already produced within the first 134 days, highlighting the quantitative importance of the slowly decomposing OC pool in permafrost. CH4 production was generally observed in active layer samples but only sporadically in permafrost samples and was several orders of magnitude smaller than CO2 production.

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Comment on "Carbon farming in hot, dry coastal areas: an option for climate change mitigation" by Becker et al. (2013)

Earth System Dynamics ◽

10.5194/esd-5-41-2014 ◽

2014 ◽

Vol 5 (1) ◽

pp. 41-42 ◽

Cited By ~ 1

Author(s):

M. Heimann

Keyword(s):

Carbon Cycle ◽

Carbon Sink ◽

Co2 Concentration ◽

Global Carbon Cycle ◽

Atmospheric Co2 ◽

Reference Scenario ◽

Carbon Cycle Model ◽

Terrestrial Carbon Sink ◽

Carbon Dioxide Co2 ◽

Global Carbon

Abstract. Becker et al. (2013) argue that an afforestation of 0.73 × 109 ha with Jatropha curcas plants would generate an additional terrestrial carbon sink of 4.3 PgC yr−1, enough to stabilise the atmospheric mixing ratio of carbon dioxide (CO2) at current levels. However, this is not consistent with the dynamics of the global carbon cycle. Using a well-established global carbon cycle model, the effect of adding such a hypothetical sink leads to a reduction of atmospheric CO2 levels in the year 2030 by 25 ppm compared to a reference scenario. However, the stabilisation of the atmospheric CO2 concentration requires a much larger additional sink or corresponding reduction of anthropogenic emissions.

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The Yale Interactive terrestrial Biosphere model version 1.0: description, evaluation and implementation into NASA GISS ModelE2

Geoscientific Model Development ◽

10.5194/gmd-8-2399-2015 ◽

2015 ◽

Vol 8 (8) ◽

pp. 2399-2417 ◽

Cited By ~ 25

Author(s):

X. Yue ◽

N. Unger

Keyword(s):

Carbon Cycle ◽

Atmospheric Chemistry ◽

Climate Model ◽

Carbon Allocation ◽

Carbon Fluxes ◽

Terrestrial Biosphere ◽

Area Index ◽

Carbon Cycle Model ◽

Model Version ◽

Vegetation Damage

Abstract. The land biosphere, atmospheric chemistry and climate are intricately interconnected, yet the modeling of carbon–climate and chemistry–climate interactions have evolved as entirely separate research communities. We describe the Yale Interactive terrestrial Biosphere (YIBs) model version 1.0, a land carbon cycle model that has been developed for coupling to the NASA Goddard Institute for Space Studies (GISS) ModelE2 global chemistry–climate model. The YIBs model adapts routines from the mature TRIFFID (Top-down Representation of Interactive Foliage and Flora Including Dynamics) and CASA (Carnegie–Ames–Stanford Approach) models to simulate interactive carbon assimilation, allocation, and autotrophic and heterotrophic respiration. Dynamic daily leaf area index is simulated based on carbon allocation and temperature- and drought-dependent prognostic phenology. YIBs incorporates a semi-mechanistic ozone vegetation damage scheme. Here, we validate the present-day YIBs land carbon fluxes for three increasingly complex configurations: (i) offline local site level, (ii) offline global forced with WFDEI (WATCH Forcing Data methodology applied to ERA-Interim data) meteorology, and (iii) online coupled to the NASA ModelE2 (NASA ModelE2-YIBs). Offline YIBs has hourly and online YIBs has half-hourly temporal resolution. The large observational database used for validation includes carbon fluxes from 145 flux tower sites and multiple satellite products. At the site level, YIBs simulates reasonable seasonality (correlation coefficient R > 0.8) of gross primary productivity (GPP) at 121 out of 145 sites with biases in magnitude ranging from −19 to 7 % depending on plant functional type. On the global scale, the offline model simulates an annual GPP of 125 ± 3 Pg C and net ecosystem exchange (NEE) of −2.5 ± 0.7 Pg C for 1982–2011, with seasonality and spatial distribution consistent with the satellite observations. We assess present-day global ozone vegetation damage using the offline YIBs configuration. Ozone damage reduces global GPP by 2–5 % annually with regional extremes of 4–10 % in east Asia. The online model simulates annual GPP of 123 ± 1 Pg C and NEE of −2.7 ± 0.7 Pg C. NASA ModelE2-YIBs is a useful new tool to investigate coupled interactions between the land carbon cycle, atmospheric chemistry, and climate change.

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Impacts of temperature and soil characteristics on methane production and oxidation in Arctic tundra

Biogeosciences ◽

10.5194/bg-15-6621-2018 ◽

2018 ◽

Vol 15 (21) ◽

pp. 6621-6635 ◽

Cited By ~ 12

Author(s):

Jianqiu Zheng ◽

Taniya RoyChowdhury ◽

Ziming Yang ◽

Baohua Gu ◽

Stan D. Wullschleger ◽

...

Keyword(s):

Transition Layer ◽

Electron Flow ◽

Oxidation Potential ◽

Organic Soils ◽

Ch4 Oxidation ◽

Microbial Decomposition ◽

Ch4 Emissions ◽

Oxidation Rates ◽

Ch4 Production ◽

Oxidation Potentials

Abstract. Rapid warming of Arctic ecosystems accelerates microbial decomposition of soil organic matter and leads to increased production of carbon dioxide (CO2) and methane (CH4). CH4 oxidation potentially mitigates CH4 emissions from permafrost regions, but it is still highly uncertain whether soils in high-latitude ecosystems will function as a net source or sink for CH4 in response to rising temperature and associated hydrological changes. We investigated CH4 production and oxidation potential in permafrost-affected soils from degraded ice-wedge polygons on the Barrow Environmental Observatory, Utqiaġvik (Barrow), Alaska, USA. Frozen soil cores from flat and high-centered polygons were sectioned into organic, transitional, and permafrost layers, and incubated at −2, +4 and +8 ∘C to determine potential CH4 production and oxidation rates. Significant CH4 production was only observed from the suboxic transition layer and permafrost of flat-centered polygon soil. These two soil sections also exhibited highest CH4 oxidation potentials. Organic soils from relatively dry surface layers had the lowest CH4 oxidation potential compared to saturated transition layer and permafrost, contradicting our original assumptions. Low methanogenesis rates are due to low overall microbial activities measured as total anaerobic respiration and the competing iron-reduction process. Our results suggest that CH4 oxidation could offset CH4 production and limit surface CH4 emissions, in response to elevated temperature, and thus must be considered in model predictions of net CH4 fluxes in Arctic polygonal tundra. Future changes in temperature and soil saturation conditions are likely to divert electron flow to alternative electron acceptors and significantly alter CH4 production, which should also be considered in CH4 models.

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Exploring Methane Emission Drivers in Wetlands: The Cases of Massaciuccoli and Porta Lakes (Northern Tuscany, Italy)

Applied Sciences ◽

10.3390/app112412156 ◽

2021 ◽

Vol 11 (24) ◽

pp. 12156

Author(s):

Stefania Venturi ◽

Franco Tassi ◽

Jacopo Cabassi ◽

Antonio Randazzo ◽

Marta Lazzaroni ◽

...

Keyword(s):

Organic Matter ◽

Climate Models ◽

Open Water ◽

Environmental Drivers ◽

Gaseous Species ◽

Microbial Decomposition ◽

Ch4 Emissions ◽

Ch4 Production ◽

Wind Exposure ◽

Diffusive Fluxes

Wetlands are hotspots of CH4 emissions to the atmosphere, mainly sustained by microbial decomposition of organic matter in anoxic sediments. Several knowledge gaps exist on how environmental drivers shape CH4 emissions from these ecosystems, posing challenges in upscaling efforts to estimate global emissions from waterbodies. In this work, CH4 and CO2 diffusive fluxes, along with chemical and isotopic composition of dissolved ionic and gaseous species, were determined from two wetlands of Tuscany (Italy): (i) Porta Lake, a small wetland largely invaded by Phragmites australis reeds experiencing reed die-back syndrome, and (ii) Massaciuccoli Lake, a wide marsh area including open-water basins and channels affected by seawater intrusion and eutrophication. Both wetlands were recognized as net sources of CH4 to the atmosphere. Our data show that the magnitude of CH4 diffusive emission was controlled by CH4 production and consumption rates, being mostly governed by (i) water temperature and availability of labile carbon substrates and (ii) water column depth, wind exposure and dissolved O2 contents, respectively. This evidence suggests that the highest CH4 diffusive fluxes were sustained by reed beds, providing a large availability of organic matter supporting acetoclastic methanogenesis, with relevant implications for global carbon budget and future climate models.

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Microtopography matters for CH<sub>4</sub> formation in a peat soil: a combined inhibitor and <sup>13</sup>C study

10.5194/bg-2016-162 ◽

2016 ◽

Author(s):

Johannes Krohn ◽

Ivana Lozanovska ◽

Yakov Kuzyakov ◽

Maxim Dorodnikov

Keyword(s):

Peat Soil ◽

Specific Inhibitor ◽

Co2 Production ◽

Surface Layers ◽

Production Rates ◽

Total N ◽

Ch4 Production ◽

Isotope Method ◽

Acetoclastic Methanogenesis ◽

Carbon Dioxide Co2

Abstract. Abstract. Peatlands’ microtopography units – hummocks and hollows – are mainly differing by hydrological characteristics (water table level, i.e. oxic-anoxic conditions) and vegetation communities. These factors affect the fluxes of key greenhouse gases (GHG) – methane (CH4) and carbon dioxide (CO2). However, the effects of microrelief forms on belowground CO2 and CH4 production and pathways of methanogenesis need deeper understanding. We hypothesized increasing CH4 and CO2 production potentials from naturally drier hummocks to more wet hollows during anaerobic incubation. GHG production in peat was expected to decrease with depth (decreasing inputs of recent plant-derived deposits) but the contribution of hydrogenotrophic vs. acetoclastic pathway to the total methanogenesis should be higher in deeper peat layers as compared to upper layers. To test the hypotheses, we measured CH4 and CO2 productions together with the respective δ13C values under controlled anaerobic conditions with- and without addition of specific inhibitor of methanogenesis (2-bromo-ethane sulfonate, BES) in a peat soil of hummocks and hollows of five depths (15, 50, 100, 150 and 200 cm). The concentration of BES (1 mM) aimed to block acetoclastic but not the hydrogenotrophic pathway of methanogenesis. As expected, CH4 production was ca. 2 times higher in hollows than in hummocks, though no differences in CO2 were measured between the microforms. With depth, CO2 production rates decreased by 77 % (15 cm vs. 200 cm) in both microforms, whereby the highest CH4 production was measured at 15 cm in hollows (91 % of total produced CH4) and at 50 cm in hummocks (82 %). Noteworthy, at 15 cm of hummocks less than 1 % of total CH4 production was observed. Decreasing GHG production rates with depth positively correlated to an increase in the extractable total N and NH4+ concentrations. The hydrogenotrophic pathway of methanogenesis in deep vs. surface layers was depicted by lower (more negative) δ13C-CH4 and higher δ13C-CO2 values, respectively. Between the microforms, overall higher contribution of hydrogenotrophic vs. acetoclastic methanogenesis corresponded to hollows as compared to hummocks. Contrary to the expectation, the addition of 1mM BES was not selective and inhibited both pathways of methanogenesis. Concluding, peatlands’ microrelief is an important factor regulating the GHG fluxes. However, the effects of microforms on the production of CH4 and pathways of methanogenesis were pronounced for the upper 50 cm layer. Finally, inhibition with BES appeared to be less effective tool for the partitioning between pathways of methanogenesis as compared with the isotope method.

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