scholarly journals Contribution of oxic methane production to surface methane emission in lakes and its global importance

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Marco Günthel ◽  
Daphne Donis ◽  
Georgiy Kirillin ◽  
Danny Ionescu ◽  
Mina Bizic ◽  
...  
Keyword(s):  
Surface Water ◽  
Methane Emission ◽  
Methane Production ◽  
Surface Mixed Layer ◽  
Atmospheric Methane ◽  
Methane Cycle ◽  
Surface Areas ◽  
Balance Analysis ◽  
Littoral Sediment ◽  
Methane Source

AbstractRecent discovery of oxic methane production in sea and lake waters, as well as wetlands, demands re-thinking of the global methane cycle and re-assessment of the contribution of oxic waters to atmospheric methane emission. Here we analysed system-wide sources and sinks of surface-water methane in a temperate lake. Using a mass balance analysis, we show that internal methane production in well-oxygenated surface water is an important source for surface-water methane during the stratified period. Combining our results and literature reports, oxic methane contribution to emission follows a predictive function of littoral sediment area and surface mixed layer volume. The contribution of oxic methane source(s) is predicted to increase with lake size, accounting for the majority (>50%) of surface methane emission for lakes with surface areas >1 km2.

scholarly journals Neonicotinoids stimulate H2-limited methane emission in Periplaneta americana through the regulation of gut bacterium community

2020 ◽  
Author(s):  
Haibo Bao ◽  
Haoli Gao ◽  
Jianhua Zhang ◽  
Haiyan Lu ◽  
Na Yu ◽  
...  
Keyword(s):  
Methane Emission ◽  
Methane Production ◽  
Periplaneta Americana ◽  
Insect Pests ◽  
Community Change ◽  
Insect Species ◽  
Atmospheric Methane ◽  
Ph Values ◽  
Acidic Conditions ◽  
Control Insect

AbstractMethane emitted by insects is considered to be an important source of atmospheric methane. Here we report the stimulation of methane emission in Periplaneta americana, an insect species with abundant methanogens, by neonicotinoids, insecticides widely used to control insect pests. The application of cycloxaprid (CYC) and imidacloprid (IMI) caused foregut expansion in P. americana, and increased the methane production and emission. Antibiotics could mostly eliminate the stimulatory effects. In P. americana gut, hydrogen levels increased and pH values decreased, which could be significantly explained by the gut bacterium community change. The proportion of several bacterium genera increased in guts following CYC treatment, and four genera from five with increased proportions could generate hydrogen at anaerobic conditions. Hydrogen is a central intermediate in methanogenesis. Gut methanogens could use the increased hydrogen to produce more methane, especially at acidic conditions. Following neonicotinoid applications, all increased methanogens in both foregut and hindgut used hydrogen as electron donor to produce methane. Besides, the up-regulation of mcrA, encoding the enzyme that catalyzes the final step of methanogenesis, suggested an enhanced methane production ability in present methanogens. In the termite Coptotermes chaohuensis, another methanogen-abundant insect species, hydrogen levels in gut and methane emission significantly increased after neonicotinoid treatment, which was similar to the results in P. americana. In summary, neonicotinoids changed bacterium community in P. americana gut to generate more hydrogen, which then stimulate gut methanogens to produce and emit more methane. The finding raised a new concern over neonicotinoid applications, and might be a potential environmental risk associated with global warming.

scholarly journals Sensitivity analysis of methane emissions derived from SCIAMACHY observations through inverse modelling

2006 ◽  
Vol 6 (5) ◽  
pp. 1275-1292 ◽  
Author(s):  
J. F. Meirink ◽  
H. J. Eskes ◽  
A. P. H. Goede
Keyword(s):  
Methane Emission ◽  
Measurement Errors ◽  
Inverse Modelling ◽  
Limiting Factor ◽  
Atmospheric Methane ◽  
Cloud Parameters ◽  
Global Emission ◽  
Spatial Coverage ◽  
Methane Source ◽  
The Impact

Abstract. Satellite observations of trace gases in the atmosphere offer a promising method for global verification of emissions and improvement of global emission inventories. Here, an inverse modelling approach based on four-dimensional variational (4D-var) data assimilation is presented and applied to synthetic measurements of atmospheric methane. In this approach, emissions and initial concentrations are optimised simultaneously, thus allowing inversions to be carried out on time scales of weeks to months, short compared with the lifetime of methane. Observing System Simulation Experiments (OSSEs) have been performed to demonstrate the feasibility of the method and to investigate the utility of SCIAMACHY observations for methane source estimation. The impact of a number of parameters on the error in the methane emission field retrieved has been analysed. These parameters include the measurement error, the error introduced by the presence of clouds, and the spatial resolution of the emission field. It is shown that 4D-var is an efficient method to deal with large amounts of satellite data and to retrieve emissions at high resolution. Some important conclusions regarding the SCIAMACHY measurements can be drawn. (i) The observations at their estimated precision of 1.5 to 2% will contribute considerably to uncertainty reduction in monthly, subcontinental (~500 km) methane source strengths. (ii) Systematic measurement errors well below 1% have a dramatic impact on the quality of the derived emission fields. Hence, every effort should be made to identify and remove such systematic errors. (iii) It is essential to take partly cloudy pixels into account in order to achieve sufficient spatial coverage. (iv) The uncertainty in measured cloud parameters may at some point become the limiting factor for methane emission retrieval, rather than the uncertainty in measured methane itself.

Livestock methane emission and its perspective in the global methane cycle

2008 ◽  
Vol 48 (2) ◽  
pp. 114 ◽  
Author(s):  
Keith R. Lassey
Keyword(s):  
Methane Emission ◽  
Feed Intake ◽  
Anthropogenic Emissions ◽  
Agricultural Expansion ◽  
Emission Inventories ◽  
Atmospheric Methane ◽  
Methane Cycle ◽  
The Past ◽  
Global Emission ◽  
Global Emissions

Over the past three centuries, the atmospheric methane burden has grown 2.5-fold, reaching levels unprecedented in at least 650 000 years. Agricultural expansion has played a large part in this anthropogenic signal, with enterically fermented methane emitted by farmed ruminant livestock accounting for about one quarter of all anthropogenic emissions. This paper summarises the range of measurements that give confidence in estimates of the emission per animal and per unit feed intake and in their extrapolation to national and global emission inventories, while noting also some of the inherent uncertainties. Global emissions are discussed in the context of the evolving global methane cycle.

scholarly journals Non-microbial methane formation in oxic soils

2012 ◽  
Vol 9 (12) ◽  
pp. 5291-5301 ◽  
Author(s):  
A. Jugold ◽  
F. Althoff ◽  
M. Hurkuck ◽  
M. Greule ◽  
K. Lenhart ◽  
...  
Keyword(s):  
Organic Matter ◽  
Large Fraction ◽  
Methane Formation ◽  
Strictly Anaerobic ◽  
Atmospheric Methane ◽  
Methane Cycle ◽  
Alternative Source ◽  
Emission Fluxes ◽  
Methane Fluxes ◽  
Methane Source

Abstract. Methane plays an important role as a radiatively and chemically active gas in our atmosphere. Until recently, sources of atmospheric methane in the biosphere have been attributed to strictly anaerobic microbial processes during degradation of organic matter. However, a large fraction of methane produced in the anoxic soil layers does not reach the atmosphere due to methanotrophic consumption in the overlaying oxic soil. Although methane fluxes from aerobic soils have been observed, an alternative source other than methanogenesis has not been identified thus far. Here we provide evidence for non-microbial methane formation in soils under oxic conditions. We found that soils release methane upon heating and other environmental factors like ultraviolet irradiation, and drying-rewetting cycles. We suggest that chemical formation of methane during degradation of soil organic matter may represent the missing soil source that is needed to fully understand the methane cycle in aerobic soils. Although the emission fluxes are relatively low when compared to those from wetlands, they may be important in warm and wet regions subjected to ultraviolet radiation. We suggest that this methane source is highly sensitive to global change.

scholarly journals Non-microbial methane formation in oxic soils

2012 ◽  
Vol 9 (9) ◽  
pp. 11961-11987 ◽  
Author(s):  
A. Jugold ◽  
F. Althoff ◽  
M. Hurkuck ◽  
M. Greule ◽  
J. Lelieveld ◽  
...  
Keyword(s):  
Organic Matter ◽  
Large Fraction ◽  
Methane Formation ◽  
Strictly Anaerobic ◽  
Atmospheric Methane ◽  
Methane Cycle ◽  
Alternative Source ◽  
Emission Fluxes ◽  
Methane Fluxes ◽  
Methane Source

Abstract. Methane plays an important role as a radiatively and chemically active gas in our atmosphere. Until recently, sources of atmospheric methane in the biosphere have been attributed to strictly anaerobic microbial processes during degradation of organic matter. However, a large fraction of methane produced in the anoxic soil layers does not reach the atmosphere due to methanotrophic consumption in the overlaying oxic soil. Although methane fluxes from aerobic soils have been observed an alternative source other than methanogenesis has not been identified thus far. Here we provide evidence for non-microbial methane formation in soils under oxic conditions. We found that soils release methane upon heating and other environmental factors like ultraviolet irradiation, and drying-rewetting cycles. We suggest that chemical formation of methane during degradation of soil organic matter may represent the missing soil source that is needed to fully understand the complete methane cycle within the pedosphere. Although the emission fluxes are relatively low when compared to those from wetlands, they may be important in warm and wet regions subjected to ultraviolet radiation. We suggest that this methane source is highly sensitive to global change.

scholarly journals The Use of Radiocarbon Measurements in Atmospheric Studies

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 37-58 ◽  
Author(s):  
M R Manning ◽  
D C Lowe ◽  
W H Melhuish ◽  
R J Sparks ◽  
Gavin Wallace ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Circulation Model ◽  
Current Data ◽  
Atmospheric Methane ◽  
Global Circulation Model ◽  
Fossil Carbon ◽  
Global Circulation ◽  
Methane Source ◽  
Clean Air ◽  
Source Current

14C measured in trace gases in clean air helps to determine the sources of such gases, their long-range transport in the atmosphere, and their exchange with other carbon cycle reservoirs. In order to separate sources, transport and exchange, it is necessary to interpret measurements using models of these processes. We present atmospheric 14CO2 measurements made in New Zealand since 1954 and at various Pacific Ocean sites for shorter periods. We analyze these for latitudinal and seasonal variation, the latter being consistent with a seasonally varying exchange rate between the stratosphere and troposphere. The observed seasonal cycle does not agree with that predicted by a zonally averaged global circulation model. We discuss recent accelerator mass spectrometry measurements of atmospheric 14CH4 and the problems involved in determining the fossil fuel methane source. Current data imply a fossil carbon contribution of ca 25%, and the major sources of uncertainty in this number are the uncertainty in the nuclear power source of 14CH4, and in the measured value for δ14C in atmospheric methane.

scholarly journals Qualitative and quantitative reconstruction of surface water characteristics and recent hydrographic changes in the Trondheimsfjord, central Norway

2013 ◽  
Vol 9 (4) ◽  
pp. 4553-4598 ◽  
Author(s):  
G. Milzer ◽  
J. Giraudeau ◽  
S. Schmidt ◽  
F. Eynaud ◽  
J. Faust
Keyword(s):  
Surface Water ◽  
Sea Surface ◽  
Surface Mixed Layer ◽  
210Pb And 137Cs ◽  
The North ◽  
Water Characteristics ◽  
Run Off ◽  
Modern Analogue ◽  
The North Atlantic Oscillation ◽  
The Impact

Abstract. In the present study we investigate dinocyst assemblages in the Trondheimsfjord over the last 25 to 50 yr from three well-dated multi-cores (210Pb and 137Cs) retrieved along the fjord axis. The downcore distribution of the cysts is discussed in view of changes of the key surface water parameters sea-surface temperatures (SSTs) and sea-surface salinities (SSSs) monitored in the fjord, as well as river discharges. We examine the impact of the North Atlantic Oscillation pattern and of waste water supply from the local industry and agriculture on the fjord ecological state and hence dinocyst species diversity. Our results show that dinocyst production and diversity in the fjord is not evidently affected by human-induced eutrophication. Instead the assemblages appear to be mainly controlled by the NAO-related changes in physico-chemical characteristics of the surface mixed layer. Still, discharges of major rivers were modulated, since 1985 by the implementation of hydropower plants which certainly influences the freshwater and nutrient supply into the fjord. The impact, however, is variable according to the local geographical setting, and barely differentiated from natural changes in river run off. We ultimately test the use of the modern analogue technique (MAT) for the reconstruction of winter and summer SSTs and SSSs and annual primary productivity (PP) in this particular fjord setting. The reconstructed data are compared with time-series of SSTs and SSSs measured at 10 m water depth, as well as with mean annual PPs along the Norwegian coast and within Scandinavian fjords. The reconstructions are in general good agreement with the instrumental measurements and observations from other fjords. Major deviations can be addressed to peculiarities in the assemblages linked to the particular fjord setting and the related hydrological structure.

scholarly journals δ 13 C methane source signatures from tropical wetland and rice field emissions

2021 ◽  
Vol 380 (2215) ◽  
Author(s):  
James L. France ◽  
Rebecca E. Fisher ◽  
David Lowry ◽  
Grant Allen ◽  
Marcos F. Andrade ◽  
...  
Keyword(s):  
Rice Field ◽  
Ambient Air ◽  
Atmospheric Methane ◽  
Isotopic Signatures ◽  
Methane Budget ◽  
Significant Seasonal Variation ◽  
Methane Source ◽  
Wetland Extent ◽  
Term Monitoring

The atmospheric methane (CH 4 ) burden is rising sharply, but the causes are still not well understood. One factor of uncertainty is the importance of tropical CH 4 emissions into the global mix. Isotopic signatures of major sources remain poorly constrained, despite their usefulness in constraining the global methane budget. Here, a collection of new δ 13 C CH 4 signatures is presented for a range of tropical wetlands and rice fields determined from air samples collected during campaigns from 2016 to 2020. Long-term monitoring of δ 13 C CH 4 in ambient air has been conducted at the Chacaltaya observatory, Bolivia and Southern Botswana. Both long-term records are dominated by biogenic CH 4 sources, with isotopic signatures expected from wetland sources. From the longer-term Bolivian record, a seasonal isotopic shift is observed corresponding to wetland extent suggesting that there is input of relatively isotopically light CH 4 to the atmosphere during periods of reduced wetland extent. This new data expands the geographical extent and range of measurements of tropical wetland and rice δ 13 C CH 4 sources and hints at significant seasonal variation in tropical wetland δ 13 C CH 4 signatures which may be important to capture in future global and regional models. This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.

scholarly journals Identification of naturally available forage species and their feeding effect on dairy cows in different climatic vulnerable areas of Bangladesh

2017 ◽  
Vol 46 (2) ◽  
pp. 150-158
Author(s):  
SMR Rahman ◽  
NR Sarker ◽  
MR Amin ◽  
M Kamruzzaman ◽  
MR Haque
Keyword(s):  
Milk Production ◽  
Methane Emission ◽  
Methane Production ◽  
Check List ◽  
Climatic Zones ◽  
Forage Species ◽  
Different Types ◽  
Prone Area ◽  
Flood Prone Area ◽  
Drought Prone Area

An investigation was carried out with the objectives to identify the naturally occurring forage species, seasonal availability, production patterns under different climatic zones and production performance and methane emission from dairy cow under existing feeding systems. For this purpose, three different agro-climatic zones of Bangladesh, namely saline prone area (Satkhira), flood plain/river basin areas (Pabna), semi-arid/drought prone areas (Chapainobabgonj) were selected. To achieve the objectives, three Focus Group Discussions (FGD) were conducted in each location to obtain more information from different age groups of farmers. A total of 9 FDGs were conducted under three selected locations and twelve participants were attended in each FGD. During FDGs, information was collected through participatory discussions through check list and also discussion was recorded to verify the information gathered as per check list.  After collection of information in each side, all the data were checked and analyzed. The results indicated that in saline area, farmers reported that different types of local grass e.g. Tale Shapna,Durba,Nona Shapna, Khud Gate/ KhudKhachra, Shama, Full Paira, Bass Pata, Math Pora/KhataShak, GhimeeShak and Baksha etc were available round the year but according to their observation Nona Shapna, Tale Shapna and Baksha were more available compared to other species of the natural grasses and these three natural forages are more suitable in this area. In the drought prone area, different types of native grasses e.g. Durba,Shama, Mutha,Katla,Kausha/Kannar, Binna, Datuloka,Shanchi, Shunshue, Bash Batari, Ulo and Binna Pati were identified and utilized by the farmers in different seasons but Durba,Katla and Mutha were found more drought tolerant compared to other species. In flood prone area, Kolmi, Shanti, Baksha, Arail, Dubla, Bokma, Vadail and Bolenga etc were found and Kolmi, Baksha and Arail are more suitable in this area. Farmers were also reported that fodder tree like Dumur/khoksha also is survive in water logging situation and or flood prone area. The study revealed that calculated total DMI (Kg/h/day) was the highest (14.14±1.06) in flood prone  followed by drought (13.80±1.30) and saline areas (4.43±0.20),  respectively. Similarly, the milk production was also higher (12.06±1.19 litre/h/day) in flood prone area followed by drought (4.47±0.60 litre/h/day) and saline (1.83±0.11 litre/h/day) areas, respectively. The calculated total methane emission (g/h/d) was significantly higher in flood prone (478.31±36.36) and the lowest in saline (153.35±7.14) prone areas. Whereas, methane production per unit of milk yield, was the lowest in flood prone (46.55±6.78) and the highest (110.48±21.69) in drought prone area and the difference was statistically significant (p<0.05).  Therefore, it may be concluded that farmers’ rearing animals under climate vulnerable areas utilizing natural grasses are more prone to higher methane production compared to animals rearing better feed resources though their availability was varied with the seasons and locations.  Hence, further research is needed to explore more suitable natural grasses in addition to introduction of high yielding fodder with higher biomass and nutritive values based on the existing cropping systems in those climate vulnerable areas for higher milk production and low enteric methane emission in the country.Bang. J. Anim. Sci. 2017. 46 (2): 150-158

scholarly journals Wetland restoration and methanogenesis: the activity of microbial populations and competition for substrates at different temperatures

2009 ◽  
Vol 6 (6) ◽  
pp. 1127-1138 ◽  
Author(s):  
V. Jerman ◽  
M. Metje ◽  
I. Mandić-Mulec ◽  
P. Frenzel
Keyword(s):  
Methane Emission ◽  
Methane Production ◽  
Iron Reduction ◽  
Carbon Mineralization ◽  
Marsh Soil ◽  
Ch4 Production ◽  
Different Temperatures ◽  
Acetoclastic Methanogenesis ◽  
Diverse Community ◽  
Water Saturated

Abstract. Ljubljana marsh in Slovenia is a 16 000 ha area of partly drained fen, intended to be flooded to restore its ecological functions. The resultant water-logging may create anoxic conditions, eventually stimulating production and emission of methane, the most important greenhouse gas next to carbon dioxide. We examined the upper layer (~30 cm) of Ljubljana marsh soil for microbial processes that would predominate in water-saturated conditions, focusing on the potential for iron reduction, carbon mineralization (CO2 and CH4 production), and methane emission. Methane emission from water-saturated microcosms was near minimum detectable levels even after extended periods of flooding (>5 months). Methane production in anoxic soil slurries started only after a lag period of 84 d at 15°C and a minimum of 7 d at 37°C, the optimum temperature for methanogenesis. This lag was inversely related to iron reduction, which suggested that iron reduction out-competed methanogenesis for electron donors, such as H2 and acetate. Methane production was observed only in samples incubated at 14–38°C. At the beginning of methanogenesis, acetoclastic methanogenesis dominated. In accordance with the preferred substrate, most (91%) mcrA (encoding the methyl coenzyme-M reductase, a key gene in methanogenesis) clone sequences could be affiliated to the acetoclastic genus Methanosarcina. No methanogens were detected in the original soil. However, a diverse community of iron-reducing Geobacteraceae was found. Our results suggest that methane emission can remain transient and low if water-table fluctuations allow re-oxidation of ferrous iron, sustaining iron reduction as the most important process in terminal carbon mineralization.

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