Methane carbon isotopes. Medical search. Frequent questions

Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us? (ansto.gov.au)
Waters collected from these springs during February-May of 2021 and 2022 are supersaturated with methane up to 600,000 times greater than atmospheric equilibration. (nature.com)
Since 2007, atmospheric methane has been rising rapidly," notes Euan Nisbet of Royal Holloway, University of London. (yale.edu)
Radiocarbon ( 14 C) is the natural radioactive carbon isotope, which is produced in the atmosphere by cosmic ray-induced reactions with atmospheric nitrogen. (uni-heidelberg.de)
In an undisturbed steady state situation the atmospheric 14 CO 2 activity corresponds to an equilibrium between its production in the atmosphere and its radioactive decay in all carbon reservoirs exchanging CO 2 with the atmosphere. (uni-heidelberg.de)
My current atmospheric research focuses on measuring methane emissions from coal seam gas, coal mining and agricultural sources. (edu.au)
In measurements of atmospheric carbon dioxide, SAM detected a roughly 5 percent increase in heavy carbon isotopes, compared to estimated isotopic compositions at the time Mars formed. (space.com)
Scientists are studying whether unusually large increases in atmospheric methane levels in 2020 and 2021 are caused by "climate feedbacks" from nature-based sources such as tropical wetlands and rice fields or whether they are caused by man-made natural gas and industrial leak. (devhardware.com)
Wetlands are the largest global source of atmospheric methane (CH4)1, a potent greenhouse gas. (lancs.ac.uk)
However, methane emission inventories from the Amazon floodplain2,3, the largest natural geographic source of CH4 in the tropics, consistently underestimate the atmospheric burden of CH4 determined via remote sensing and inversion modelling4,5, pointing to a major gap in our understanding of the contribution of these ecosystems to CH4 emissions. (lancs.ac.uk)
The air bubbles trapped in the ice core are direct samples of ancient atmospheric gas composition (e.g. methane, carbon dioxide). (radiocarbon.com)
The chemical composition of snow layers provides detailed information on temperature (including seasonal temperature variations and extreme climate change events) through the analysis of stable oxygen isotopes as well as changes in atmospheric conditions (particularly in combination with dust inclusion analysis) (e.g. (radiocarbon.com)
Finally, atmospheric dust and other aeolian deposits found within ice core layers can be analyzed using strontium, neodymium and hafnium isotopes to identify source origin. (radiocarbon.com)
2021). For example, 14 C ages can be deduced in ice cores by measuring the water-insoluble organic carbon fraction or the dissolved organic fraction within the ice - particles that are integrated through time from atmospheric deposition. (radiocarbon.com)

This information is necessary to constrain how lacustrine methane production, oxidation and emissions are expected to respond to global change drivers. (diva-portal.org)
We estimate annual methane emissions from proglacial groundwaters to be up to 2.31 kt across the Svalbard archipelago. (nature.com)
What is Causing the Recent Rise in Methane Emissions? (yale.edu)
Methane emissions from rice fields, such as this one in India, have risen in recent years. (yale.edu)
The cause of the rapid increase in methane emissions since 2007 has puzzled scientists. (yale.edu)
It turns out that, all along, natural gas and other fossil fuels have been a bigger source of methane emissions than the industry has declared in submissions to governments and the UN. (yale.edu)
Second, satellite observations of methane concentrations in the air are allowing researchers to accurately identify the regions of the world from which increases in emissions are occurring. (yale.edu)
First, the recent methane surge into the atmosphere is due not to the rising fossil-fuel emissions, but rather to an unexpected surge in microbial sources. (yale.edu)
Microbial methane still accounts for the majority of emissions, totalling almost 400 million tons a year, but fossil-fuel emissions are much more significant than previously thought, at about 200 million tons. (yale.edu)
Measurement of greenhouse gas emissions and carbon accounting. (edu.au)
Botanists find no evidence for methane emissions. (nature.com)
If methane emissions are coming from forests then that probably just means less from wetlands. (nature.com)
It's hard to imagine who methane emissions would fit in with any of these known emissions pathways. (realclimate.org)
Global temperature increased about 6°C over 20,000 years due to an abrupt release of carbon to the atmosphere (though this was not as abrupt as current emissions). (barbrastreisand.com)
The WMO Greenhouse Gas Bulletin stated that "global emissions have rebounded since the COVID-related shutdowns" and that increases in methane levels in 2020 and 2021 were the largest since systematic record-keeping began in 1983. (devhardware.com)
The study comes on the same day that a new United Nations report was released that says that the world's governments have not committed to this Reduce enough carbon emissions putting the world on track to increase global temperatures by 2.5°C (4.5°F) by the end of the century. (devhardware.com)
The fastest way to influence the pace of global warming is to reduce emissions of methane, the second largest contributor to climate change. (devhardware.com)
It may even be the beginning of a dangerous global warming acceleration in methane emissions from wetlands and other natural systems that we have been concerned about for decades," Jackson cautioned. (devhardware.com)
If organic matter decomposes in water - without oxygen - this leads to methane emissions. (devhardware.com)
Russian scientists have built a model of the formation of craters appearing in permafrost as a result of methane emissions. (northernforum.org)
Such natural processes with the formation of large funnels can be dangerous for human life in the Arctic, which necessitates their prediction based on the results of studying gas sources, primarily methane, their accumulation mechanisms in the upper permafrost horizons and the conditions for the occurrence of explosive gas emissions. (northernforum.org)
And so it has proved: the country that adopted shale gas first and most - the United States - is the country that lowered its carbon dioxide emissions first and most, because gas displaced coal, a much higher-carbon fuel. (akdart.com)
Methane fluxes from Amazon tree stems were up to 200 times larger than emissions reported for temperate wet forests6 and tropical peat swamp forests7, representing the largest non-ebullitive wetland fluxes observed. (lancs.ac.uk)
Emissions from trees had an average stable carbon isotope value (δ13C) of −66.2 ± 6.4 per mil, consistent with a soil biogenic origin. (lancs.ac.uk)
The project uses eddy covariance data, footprint modelling, manual chamber measurements, drone imagery and tower-based spectral measurements to track the growth of new vegetation and evaluate the effects of salvage-logging versus natural regeneration on the ecosystem microclimate and carbon flux emissions. (lu.se)

They managed not only to build a model of its formation, but also to establish the source of methane. (northernforum.org)

Permafrost and glaciers in the high Arctic form an impermeable 'cryospheric cap' that traps a large reservoir of subsurface methane, preventing it from reaching the atmosphere. (nature.com)
At sufficiently high pressures and low temperatures, the methane beneath permafrost and glaciers can be trapped as a solid gas hydrate 6 . (nature.com)
These forefields provide an outlet for subpermafrost groundwaters that were previously sealed beneath the overburden glacier and permafrost and facilitate the formation of terrestrial methane seepage (Fig. 1 ). (nature.com)
Fig. 1: Conceptual model of methane-rich proglacial groundwater springs associated with glacier-permafrost coupling. (nature.com)
This warming led to a certain amount of seabed permafrost degradation but until recently the remaining subsea permafrost layer was thought to be relatively stable, acting as a cap or lid to the methane that was expected to be present in and beneath it. (skepticalscience.com)
Permafrost degradation and methane release on land are things that most people will be familiar with: footage of people igniting methane on frozen Siberian lakes has been broadcast many times. (skepticalscience.com)
As permafrost degrades due to the warming climate, the organic matter, trapped in the frozen ground for thousands of years, is freed and bacterial decay rapidly sets in, releasing methane to the atmosphere. (skepticalscience.com)
N inputs from permafrost degradation and seasonal river N trends were identified using isotopes, helping to predict climate change impacts. (copernicus.org)
Under conditions of warming and the gradual destruction of permafrost, methane in the depths is released and breaks out to the surface in the form of a powerful explosive release. (northernforum.org)
On the other hand, climate change will lead to even greater methane release from permafrost. (northernforum.org)

Methane gas in the Martian atmosphere is concentrated in three specific regions, according to the most sensitive measurements yet made. (newscientist.com)
Either way, the lifetime of methane in the atmosphere is unexpectedly short. (newscientist.com)
In 2006, methane levels in the Martian atmosphere were 50% lower during the local springtime than they were in the 2003 Martian summer. (newscientist.com)
The amount of methane in the atmosphere has more than doubled in the past 250 years. (yale.edu)
The subsequent decrease is due to carbon exchange between atmosphere, ocean and biosphere. (uni-heidelberg.de)
NASA's Mars rover Curiosity has detected no methane in its first analyses of the Martian atmosphere - news that will doubtless disappoint those who hope to find life on the Red Planet. (space.com)
Living organisms produce more than 90 percent of the methane found in Earth's atmosphere, so scientists are keen to see if Curiosity picks up any of the gas in Mars' air. (space.com)
Scientists have detected methane in Mars' atmosphere before, using a variety of instruments on the ground and in space. (space.com)
Scientists believe that Mars' methane "sinks" are quite efficient, removing the gas from the atmosphere every few hundred years. (space.com)
To tackle this problem, Dueck and his team grew plants in an atmosphere of 'heavy' carbon dioxide enriched in the isotope carbon-13 to give any methane produced a recognizable isotopic signature. (nature.com)
For example, as carbon dioxide in the atmosphere is absorbed by the ocean, it causes the pH to lower in a process called ocean acidification. (usgs.gov)
A new paper in Science examines the geologic record for context relating to ocean acidification, a lowering of the pH driven by the increased concentration of carbon dioxide in the atmosphere. (barbrastreisand.com)
The isotopic composition of carbon changes with shifts in the carbon cycle, such as the movement of greenhouse gases like methane and carbon dioxide in the atmosphere. (barbrastreisand.com)
Methane is gas that is found in small quantities in Earth's atmosphere. (windows2universe.org)
The amount of methane in the atmosphere is racing at an accelerating pace, according to a study by the World Meteorological Organization, threatening to undermine efforts to slow climate change. (devhardware.com)
The World Meteorological Organization said the amount of methane in the atmosphere jumped 15 parts per billion in 2020 and 18 parts per billion in 2021. (devhardware.com)
A World Meteorological Organization study said levels of two other major greenhouse gases in the atmosphere - carbon dioxide and nitrous oxide - also reached record levels in 2021. (devhardware.com)
Methane is a powerful greenhouse gas, and its release into the atmosphere can accelerate global warming, scientists say. (northernforum.org)
These organic carbon samples typically originate from the terrestrial biosphere and thus should be in equilibrium with the atmosphere. (radiocarbon.com)

The abundance of the clumped isotopes provides information independent from the traditional carbon or hydrogen isotope composition of methane molecules. (wikipedia.org)
Clumped isotope composition is calculated relative to the random distribution of carbon and hydrogen isotopes in the methane molecules. (wikipedia.org)
In thermodynamic equilibrium, methane clumped isotopologue composition has a monotonic relationship with formation temperature. (wikipedia.org)
When methane clumped-isotope composition is controlled by kinetic effects, for example, for microbial methane, it has the potential to be used to study metabolism. (wikipedia.org)
Analyses of the sulfur isotopic composition (δ 34 S) of pyrite from methane-bearing sediments have typically focused on bulk samples. (jove.com)
In the Greenhouse Gas Measurement laboratory we can analyse the isotopic composition of carbon dioxide, methane and nitrous oxide gases. (edu.au)
Validation of the correlation between Niobrara and Codell production GOR and stable isotope composition was provided by an independent geochemistry dataset from the USGS. (onepetro.org)

Reports of extensive areas of methane - a powerful greenhouse gas - bubbling up through the shallow waters of the East Siberian Arctic Shelf (ESAS) have been doing the rounds in the media recently, with some articles taking the apocalyptic approach and others the opposite. (skepticalscience.com)
Methane is a powerful greenhouse gas. (windows2universe.org)

Specifically, as Feehan had done, Stoddard looked at the ratios of two carbon isotopes, or versions of an element containing different numbers of neutrons. (livescience.com)
Isotopes are versions of an element that have different numbers of neutrons in their atomic nuclei. (space.com)

Stable isotope analysis can be executed pre-completion on samples obtained from mud gas and/or gas desorbing from cuttings and core. (onepetro.org)
These results demonstrate the potential of natural gas stable isotope signatures as a useful and reliable fluid quality prediction tool. (onepetro.org)
Study in-vivo metabolic processes by integrating our unique stable isotope analyzer. (sablesys.com)

Methane (CH4) contains two elements, carbon and hydrogen, each of which has two stable isotopes. (wikipedia.org)
while for hydrogen, 99.99% are in the form of protium (1H) and 0.01% are deuterium (2H or D). Carbon-13 (13C) and deuterium (2H or D) are rare isotopes in methane molecules. (wikipedia.org)
The absolute abundance of each isotopologue primarily depends on the traditional carbon and hydrogen isotope compositions (δ13C and δD) of the molecules. (wikipedia.org)
Methane (CH 4 ) has one carbon atom and four hydrogen atoms. (windows2universe.org)
Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. (windows2universe.org)
Stable carbon (δ¹³C) and hydrogen (δ²H) isotopes have been used to characterize hydrocarbons for exploration, development and production since the 1960s, and have re-emerged as predictive tools with the development of unconventional "tight" oil and gas plays. (onepetro.org)
Maturities derived from carbon and hydrogen isotopes can serve as controls in regional maturity maps, which are used to help define areas of oil, wet gas and dry gas production. (onepetro.org)
Stable carbon and hydrogen isotope values show a strong correlation to both initial and cumulative GOR for the unconventional Niobrara and Codell intervals of Wattenberg Field. (onepetro.org)

The notation of traditional isotopes are defined as: δ = ( ( R s a m p l e R r e f e r e n c e ) − 1 ) × 1000 {\displaystyle \delta =(\left({\frac {R_{sample}}{R_{reference}}}\right)-1)\times 1000} ‰ R s a m p l e {\displaystyle R_{sample}} is the ratio of the rare isotope to the abundant isotope in the sample. (wikipedia.org)
Methane molecules from each of these sources have a characteristic ratio of two carbon isotopes, carbon-12 and carbon-13. (yale.edu)
Life alters the typical ratio of C-12 to C-13 because most biochemical processes -eating, growth, and so on - divide isotopes into lighter and heavier camps. (livescience.com)
Moreover, the ratio of methane to the total volume of its homologues - ethane and propane - indicated the flow of gas from deep layers. (northernforum.org)
Gases sampled for this study were analyzed for both CO 2 concentration and the carbon isotope ratio δ13C (CO 2 ), as possible source indicators. (confex.com)
The stable carbon isotope ratio (δ 13 C) is included as part of the service, which can provide evidence of carbon cycle changes through time. (radiocarbon.com)

First is a new database of isotopic analyses of methane in the air. (yale.edu)
Isotope analyses help attribute the sources of greenhouse gases measured in ambient air samples and gases stripped from groundwater. (edu.au)
Chanton was using isotope analyses to track the Deepwater Horizon oil spill and its potential impacts on the marine food web. (gulfresearchinitiative.org)

Microbes fractionate the isotopes, increasing the proportion of carbon-12 compared to fossil methane. (yale.edu)
This carbon signature is usually produced by microbes that excrete the carbon-containing compound methane. (livescience.com)
Until last year, methane was thought to be produced almost exclusively by microbes either in natural settings, such as swamps, or artificial ones, such as landfills, and in the guts of domesticated cattle. (nature.com)
2006), threatened to overturn this microbes-only view of the global methane cycle. (nature.com)

One reason that the matter has not already been settled is that the amount of methane produced by each plant is low relative to the ambient methane concentration. (nature.com)

However, only limited information is available about the extent to which, at the ecosystem scale, variations in abundance and availability of MOB reflect past changes in in-lake methane concentrations. (diva-portal.org)
We present a study examining the abundances of fatty acids (FAs), particularly of C-13-depleted FM known to be produced by MOB, relative to methane concentrations in 29 small European lakes. (diva-portal.org)
39 surface sediment samples were obtained from these lakes and FA abundances were compared with methane concentrations measured at the lake surface, 10 cm above the sediments and 10 cm within the sediments. (diva-portal.org)
We observed positive relationships between methane concentrations and relative abundances of C-16:1 omega 7c, C-16:1 omega 5c/t, and C-18:1 omega 7c and the sum of these FAs. (diva-portal.org)
Our results confirm that robust relationships exist between in-lake CH 4 concentrations and 13 C-depleted groups of FAs in the examined sediments, agreeing with earlier suggestions that the availability of MOB-derived, C-13-depleted organic matter for aquatic invertebrates increases with increasing methane concentrations. (diva-portal.org)
Methane concentrations may vary somewhat by region and over time. (space.com)
Methane concentrations are not only rising, they are rising faster than ever before," said Rob Jackson, professor of Earth system sciences at Stanford University. (devhardware.com)
The concentrations of carbon dioxide in 2021 were 415.7 parts per million (or parts per million), methane at 1908 parts per billion (ppb) and nitrous oxide at 334.5 parts per million. (devhardware.com)
CO 2 gas concentrations at DSF ranged from 93.4 to 98.4 percent and concentration at La Brea reached 20.8 percent with the remaining gas being mostly methane. (confex.com)

Further investigations into marine-terminating glaciers indicate future methane emission sources as these glaciers transition into fully land-based systems. (nature.com)
But if you are going to look for a mechanism [for methane emission], first you have to be able to measure it. (nature.com)

On Svalbard, where air temperatures are rising more than two times faster than the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape. (nature.com)
Our findings reveal that climate-driven glacial retreat facilitates widespread release of methane, a positive feedback loop that is probably prevalent across other regions of the rapidly warming Arctic. (nature.com)
This study presents evidence that these seepage pathways induce widespread groundwater-driven methane escape from glacial forefields in the Eurasian High Arctic, a region known for its vast subpermafrost gas reserves 1 . (nature.com)

The overall goal of this procedure is to analyze the In Situ sulfur isotopic compositions of various pyrite generations by secondary ion mass spectroscopy in order to understand the diagenetic history of pyritization in methane bearing sediments. (jove.com)
Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, 13 CH 3 D) has recently emerged as a proxy for determining methane-formation temperatures. (psu.edu)

The stomachs of cattle, fermentation in rice fields, fracking for natural gas, coal mines, festering bogs, burning forests - they all produce methane, the second most important greenhouse gas, after carbon dioxide. (yale.edu)
There are some rare abiotic mechanisms which can produce methane but the probability that those account for it are slim. (uncommondescent.com)

Isotopes of dissolved inorganic carbon and strontium, along with water quality data, were used to characterize the CBNG reservoirs and hydrogeologic systems of Wyoming's Atlantic Rim. (usgs.gov)
Organic matter (OM) turnover into dissolved inorganic carbon (DIC) was investigated by means of carbon isotope mass balances in Germany's largest water reservoir. (copernicus.org)

In the samples of underground ice, carbon isotopes were found in an amount characteristic of biogenic hydrocarbons. (northernforum.org)
Kelsey Rogers looks for evidence of oil and methane intrusion into Gulf of Mexico water and sediment, but finding these hydrocarbons is only the beginning of her work. (gulfresearchinitiative.org)
Kelsey can trace these hydrocarbons' path through the water column using the carbon isotopes. (gulfresearchinitiative.org)

Since 2018 I have been affiliated with the United National Environment Programme Methane Science Studies team, which completed the world's. (edu.au)
Since 2018 I have been affiliated with the United National Environment Programme Methane Science Studies team, which completed the world's first airborne measurements of greenhouse gases from coal seam gas fields. (edu.au)
As a postdoc, I am investigating how wildfire severity and different types of forest management are affecting the carbon balance of forests recovering from a major wildfire in central Sweden in 2018. (lu.se)

This is primarily biogenic methane - formed via microbial decay of organic matter such as plant-debris. (skepticalscience.com)
We describe isotopic tracers that provide immediate data on the presence or absence of biogenic natural gas and the identify methane-containing reservoirs are hydrologically confined. (usgs.gov)

The increase in carbon dioxide levels from 2020 to 2021 was greater than the average," it said. (devhardware.com)

The likeliest explanation is that lifeforms, once buried deep in the Earth's crust, altered the ancient aragonite's carbon signature. (livescience.com)

Oxygen and Carbon Dioxide Rhythms Are Circadian Clock Controlled and Differentially Directed by Behavioral Signals. (sablesys.com)

Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters. (psu.edu)

Yet methane from burning trees or crop residues has a higher proportion of carbon-13, because photosynthesis favors that isotope. (yale.edu)
Maybe the point is in nighttime lack of oxidation, as photosynthesis is stopped, but methane synthesis as precursor for methanol still is functioning… VOC production also increases in stress situations (like cutting grass, wounding trees). (realclimate.org)

We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tonnes of methane," team member Geronimo Villanueva of the Catholic University of America in Washington, DC, said in a statement. (newscientist.com)
The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporised, allowing methane to seep into the Martian air. (newscientist.com)
The evidence is methane plumes. (uncommondescent.com)

This method can help identify the biogeochemical processes that impact pyritazation, like organiclastic sulfur reduction and sulfur-driven anaerobic oxidation of methane which can now be resolved by a box of isotopic analyzers. (jove.com)
Denitrifying anaerobic methane-oxidizing (DAMO) processes, which link anaerobic methane oxidation (AMO) and denitrification, have a promising prospect in anaerobic wastewater treatment. (bvsalud.org)

Methane clumped isotopes are methane molecules that contain two or more rare isotopes. (wikipedia.org)
At greater depths in the sedimentary column, methane may exist in a second form, trapped in clathrate molecules. (skepticalscience.com)

Possible non-biological sources of methane include comet strikes, degradation of interplanetary dust motes by ultraviolet light and water-rock interactions, researchers said. (space.com)
We focused on nitrogen (N) release from this degradation and associated cycling using N isotopes, an understudied area. (copernicus.org)

Detailed knowledge about how climate and human activities influence the sources and sinks of greenhouse gases like carbon dioxide and methane is needed in order to make the informed and effective decisions needed for combating climate change. (lu.se)

This is the condition for many geological environments so that methane clumped isotope can record its formation temperature, and therefore can be used to identify the origins of methane. (wikipedia.org)
However, we also show that these relationships are complex, with different relationships observed for oxic and anoxic sediments and highest values measured in sediments deposited in oxic environments overlain with relatively methane-rich water. (diva-portal.org)
This sensitivity to temperature and pressure means that outside of very deep water environments, methane hydrate typically occurs at considerable depths in the sedimentary column (ref. 1): values of 200-500m beneath surface are commonly cited as being within the 'gas hydrate stability zone' (GHSZ). (skepticalscience.com)

My research combines remote sensing data at multiple spatial scales with carbon flux measurements and footprint modelling to monitor how boreal ecosystems are responding to climate change and natural disturbances. (lu.se)

Working in the UNC isotope geochemistry lab, Kelsey wrote a research paper about using carbon isotope evidence from deer teeth to identify where the animals lived. (gulfresearchinitiative.org)

This is the very first evidence of local methane sources," Mumma told New Scientist . (newscientist.com)
Sunlight breaks apart methane in some 350 years or so, but the team found evidence of a much faster destruction process. (newscientist.com)
Spatial sampling reveals a geological dependency on the extent of methane supersaturation, with isotopic evidence of a thermogenic source. (nature.com)

Autochthonous particulate organic carbon (POC) was the main contributor to DIC, with rates that were highest for the MOM. (copernicus.org)
Kelsey identifies the carbon isotopes in Gulf particulate and sediment samples to track oil and methane through the marine ecosystem. (gulfresearchinitiative.org)

But new research finds some surprising culprits in the methane surge and shows that fossil-fuel sources have played a much larger role over time than previously estimated. (yale.edu)
By combining research approaches, a previously fuzzy image of methane sources is becoming dramatically clearer. (yale.edu)
As the two approaches are combined, a previously fuzzy image of methane sources is becoming dramatically clearer. (yale.edu)
Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. (psu.edu)
Dueck says that Keppler's group kept plants in sealed plastic containers instead of flow chambers, and exposed them to sources of stress such as bright sunlight and high temperature, which could have produced methane as an artefact. (nature.com)
Une fois que la poussière se sera redéposé, la situation pourrait ne pas être si différente que celle précédent cette étude - certaines émissions pouvant s'avérer avoir été mal interprétées, cette source pouvant ne pas être aussi importante que suggérée par ces évaluations initiales (10-30% de sources totales), ou au contraire elle pourrait radicalement défier notre compréhension actuelle des sources et puits du méthane. (realclimate.org)
The methane emitted from fossil sources contains more of the carbon-13 isotope than that from wetlands or livestock. (devhardware.com)
We're not seeing any increase" in methane from fossil sources, said Antoine Halfe, senior analyst and co-founder of Kayross, which conducts an extensive analysis of satellite data. (devhardware.com)
It "creates an unprecedented opportunity to use gas as a bridge fuel to a twenty-first-century energy economy that relies on efficiency, renewable sources, and low-carbon fossil fuels such as natural gas," wrote Senator Tim Wirth, a prominent environmentalist. (akdart.com)

Methane hydrate looks just like ice: it is a white, crystalline solid but is only stable at low temperatures and/or high pressures: otherwise it decomposes, liberating its methane content. (skepticalscience.com)

Some observations hinted that the gas was not distributed evenly across the planet , but the source of the methane remained unclear. (newscientist.com)
The previous observations, particularly those from Mars Express , gave only a hint of broad areas of possibly large abundances of methane," he told New Scientist . (newscientist.com)

During my PhD, I developed new methods for modelling and upscaling carbon fluxes in boreal peatlands, which focused specifically on using thermal cameras (on towers, drones and satellites) to collect high resolution surface temperature data. (lu.se)

The first mass spectrometry measurement of methane clumped isotopologues of natural abundance was made in 2014. (wikipedia.org)
Assuming isotopes are randomly distributed throughout all isotopologues and isotopes are of natural abundance. (wikipedia.org)
Several of the available proxies for reconstructing methane cycle changes of lakes rely on interpreting past changes in the abundance or relevance of methane oxidizing bacteria (MOB), either directly (e.g. via analysis of bacterial lipids) or indirectly (e.g. via reconstructions of the past relevance of MOB in invertebrate diet). (diva-portal.org)

Above: methane hydrate forming irregular white masses embedded in the marine sediment of Hydrate Ridge, in the Pacific Ocean off Oregon. (skepticalscience.com)

The carbon cycle group at IUP investigates the biogeochemical cycles of long-lived greenhouse gases such as CO 2 , CH 4 N 2 O and SF 6 on the regional but also on the global scale. (uni-heidelberg.de)
In the last decade, the IUP carbon cycle group contributed to the design and implementation of the European Research Infrastructure ICOS ( Integrated Carbon Observation System ) and has set up in Heidelberg the Central Radiocarbon Laboratory (CRL) as part of the Central Analytical Laboratory of ICOS. (uni-heidelberg.de)
I mean if plants have always emitted methane then you would have expected to methane level to rise so it must be accounted for by some part of the carbon cycle. (realclimate.org)
LUCCI was a research centre at Lund University devoted to studies of the carbon cycle and how it interacts with the climate system. (lu.se)
Working together in a creative cross-disciplinary environment, our goals are to increase the understanding of how the carbon cycle and climate system function and interact, and to disseminate our findings to society. (lu.se)
Although progress has been made in our understanding of the carbon cycle and climate there are several fundamental science questions that remain unanswered and that are pivotal for an increased understanding of the Earth System as well as for our ability to predict future changes through modeling. (lu.se)
How do possible increased extreme events such as devastating storms and flooding affect carbon cycle processes and do we already see such perturbations? (lu.se)

In brief, a 100µL plasma sample was spiked with 100µL of a mixture of 11 internal standards (fatty acids labeled with stable isotopes) to account for recovery. (cdc.gov)

Natural seeps in the gulf are like hydrocarbon springs, releasing oil and methane to the Gulf's water column. (gulfresearchinitiative.org)

Using a mass spectrometer at FSU, she calculates the stable carbon isotopes and then sends them to the University of Georgia to analyze their radiocarbon levels. (gulfresearchinitiative.org)

My work has involved close collaboration with colleagues from Gothenburg University, SLU and Swansea University and uses data from national research infrastructures such as ICOS (Integrated Carbon Observation System) and SITES (Swedish Infrastructure for Ecosystem Science). (lu.se)

Here we document how methane-rich groundwater springs have formed in recently revealed forefields of 78 land-terminating glaciers across central Svalbard, bringing deep-seated methane gas to the surface. (nature.com)
Increased summer ablation and rapidly expanding glacial forefields due to glacial retreat are causing new methane seepage pathways to form in association with proglacial groundwater springs. (nature.com)

Carbon dioxide (CO 2 ) released from burning of fossil fuels is void of radiocarbon. (uni-heidelberg.de)
Kelsey studies the stable and radiocarbon levels to determine how much oil and/or methane is present, how old it is, and where it originated. (gulfresearchinitiative.org)
Miami-based Beta Analytic provides radiocarbon dating of the organic carbon fraction of water (melted ice) providing the sample meets a minimum DOC concentration of 5.0 mg C/L (5.0 ppm). (radiocarbon.com)

The problem of how to explain puzzlingly high methane levels found above certain forests remains. (nature.com)

Kelsey learned about Chanton's oil spill research and saw a natural fit with her ecological research using carbon isotopes. (gulfresearchinitiative.org)
The USGS is investigating domestic natural accumulations of carbon dioxide (CO 2 ). (confex.com)

Since methane was first discovered on Mars in 2003, three teams have found signatures of the gas using ground-based telescopes as well as Europe's Mars Express orbiter. (newscientist.com)
By observing Mars through a long, narrow slit, the team built up a high-resolution map of methane as the planet rotated. (newscientist.com)
Moreover, the Mars Express results relied on a single strong spectral line of methane, whereas the current data identify at least two lines, which gives more confidence in the presence of methane on Mars. (newscientist.com)
Mars Methane: Could It Mean Life? (space.com)
At this time, we don't have a positive detection of methane on Mars ," said Sushil Atreya of the University of Michigan, a SAM co-investigator. (space.com)
But that could change over time, depending on how methane is produced and how it is destroyed on Mars. (space.com)

An outcrop there containing veins of the mineral aragonite, dredged up to the surface scores of millions of years ago by geological processes, was found to contain weirdly high levels of a lightweight version of the element carbon . (livescience.com)

Pockets of methane might have been produced long ago by the interaction of water and volcanic rock below the Martian surface. (newscientist.com)

Anatomy3

Organisms32

Diseases2

Chemicals and Drugs54

Analytical, Diagnostic and Therapeutic Techniques and Equipment13

Phenomena and Processes38

Disciplines and Occupations4

Anthropology, Education, Sociology and Social Phenomena3

Technology, Industry, Agriculture2

Humanities1

Information Science2

Health Care17

Geographicals1

Atmospheric14

Emissions25

Source of methane1

Permafrost10

Atmosphere19

Composition7

Powerful greenhouse gas2

Different numbers of neutrons2

Stable isotope3

Hydrogen8

Ratio6

Analyses3

Microbes4

Amount of methane1

Concentrations9

Emission2

Arctic3

Isotopic compositions2

Produce methane2

Inorganic carbon2

Hydrocarbons3

20183

Biogenic2

20211

Earth's1

Oxygen1

Thermometry1

Photosynthesis2

Plumes3

Anaerobic2

Molecules2

Degradation2

Sinks1

Environments3

Measurements1

Geochemistry1

Evidence3

Particulate2

Sources9

Pressures1

Observations2

Boreal1

Abundance3

Sediment1

Cycle7

Fatty1

Hydrocarbon1

Spectrometer1

Integrated Carbon Observation System1

Groundwater2

Radiocarbon3

Forests1

Natural2

Mars6

Processes1

Martian1