Sentences with phrase «isotopic signature»

The study focused on unique isotopic signatures of methane from different sources.

On the AAE 2013 - 2014 we undertook to map the stable isotopic signatures in seals to investigate whether there has been a change in diet over time.

The probability that the impactor just happened to have the same isotopic signature as Earth was vanishingly small.

Its main natural sources are tropical and boreal wetlands, ruminant animals and biomass burning, all of which have different isotopic signatures for carbon and hydrogen.

This we know pretty thoroughly, due to the distinctive isotopic signature of the rise.

The methane stable isotopic signature indicated production through acetoclastic methanogenesis, but gene signatures from acetoclastic and hydrogenotrophic methanogenic Archaea were detected in both polygonal and runnel ponds.

The results, published online today in Science, reveal that the inclusions have a much lighter isotopic signature than does the ocean, suggesting that the composition of seawater has indeed evolved over time.

They measured and analyzed the samples for inorganic contaminants and to identify the unique isotopic signature, or fingerprint, of Bakken region brines.

Although these processes are known to produce varied isotopic signatures on local scales, it is uncertain whether wetland emissions that reach the broader atmosphere have a more coherent signature.

The probability that the impactor just happened to have the same isotopic signature as the Earth was vanishingly small.

When he analyzed isotopic signatures of carbon and nitrogen found in the tissues of some of the small cave crustaceans, he discovered that the animals had a food source fueled by something other than the sun.

Since the reaction produces nitrous oxide with a specific isotopic signature, Joye says: «This could be an easy way to «sniff» around the surface of Mars looking for pockets of subsurface brine that might be hotspots for extreme microbial life.»

Their integration also enables us delineate the initial radium isotopic signatures of the spill waters, indicating the nature of the wastewater that caused the spill.»

The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19th century and remains a significant source today, the authors report.

Because life prefers lighter carbon, the isotopes suggest to some scientists that the atmospheric rise must be due to extra microbial production, and not a boost due to leaked gas from fracking operations, which has a heavier isotopic signature.

Based on measurements of Jupiter and the solar wind, which are thought to preserve the hydrogen isotopic ratio of the protosolar nebula, scientists think nebular water had an extremely light hydrogen isotopic signature — much closer to what the Baffin Island lavas suggest about the deep mantle's water.

Sharpe admits that's a possibility, but she thinks the dogs» isotopic signature doesn't quite match the signal you'd expect from dogs consuming maize - heavy feces.

Isotope geochemist Mukul Sharma of Dartmouth College in Hanover, New Hampshire, says he has been unable to find any significant amount of platinum - group elements with the distinctive isotopic signature showing that they came from space.

Peter Weber is a member of the Chemical & Isotopic Signatures group.

«Using more sophisticated physics and powerful super-computers, we managed to remove the systematic biases that plague traditional modeling and have previously led to false identifications of the 6Li / 7Li isotopic signature.»

This could shift the overall isotopic signature by enough to mask a rise in emissions linked to natural gas.

[13][citation needed] The methane in clathrates typically has a biogenic isotopic signature and highly variable δ13C (− 40 to − 100 ‰), with an approximate average of about − 65 ‰.

Terrestrial basalts have a unique iron isotopic signature taken as fingerprints of core formation.

In contrast, lower - concentration samples from shallow groundwater at nonactive sites had isotopic signatures reflecting a more biogenic or mixed biogenic / thermogenic methane source.

By looking at the distinct isotopic signatures, the researchers could differentiate between methane produced from fracking, for instance, and methane produced from agriculture, because they each have different signatures.

That helped narrow down the sources, Schaefer says, because different types of wetlands have different isotopic signatures.

Moreover, it is possible to both discriminate between these sources by isotopic signature and close (airborne) monitoring.

Methane release alters the tiny shells of «forams» and leaves a distinctive isotopic signature that can be examined my scientists.

The methanogenic pathways and C age were investigated through stable isotopic signatures and radiocarbon dating of dissolved and bubbling GHG.

Methane produced by these microbial communities tends to have a lighter isotopic signature than that produced by other means, such as fossil fuel burning.

Although measurements at the wetland - air interface displayed considerable heterogeneity, the air samples show that the methane emissions rapidly mix just above the surface, creating a uniform regional carbon - 13 isotopic signature of − 71 ‰ ± 1 ‰.

They found that the isotopic signatures of sulfur (in sulfate), carbon (in dissolved inorganic carbon) and strontium from water samples collected from tributaries adjacent to mountaintop mining sites are distinguishable from those collected from unaffected upstream waters.

But planetary bodies that formed in different parts of the solar system generally have different isotopic compositions, so different that the isotopic signatures serve as «fingerprints» for planets and meteorites from the same body.

Animals that live in the sea have ratios of carbon and nitrogen isotopes that differ from those found in terrestrial animals, and this isotopic signature is passed on to the people who eat them.

Rubenstein analyzed the isotopic signatures of feathers from wintering warblers to reveal the location of their breeding sites.

That scenario has been bolstered by similarities in the isotopic signatures of the asteroids and seawater.

Scientists have often assumed that the isotopic signature of seawater is close to the true value, but Hallis thinks this has probably changed over geologic time, as Earth preferentially lost light hydrogen atoms to space and gained water from asteroid and comet impacts.

For example, the isotopic signatures of ice cores depend on the seasonal distribution of precipitation.

Because the tiny zircon crystals retain their isotopic signatures despite episodes of remelting, the researchers could date their cores at 0.8 million to 2.1 million years old.

These gases would be carried away in the atmosphere after an explostion and investigators could look for the isotopic signatures thousands of kilometers away from the test site and even months afterward.

Each sample is brought to the surface, analyzed for its nitrate concentration and labeled with an isotopic signature.

«Adding neodymium changed that picture and gave us an independent measure of the amount coming from shallow continental waters that carried an isotopic signature of life.»

To test this hypothesis, the possible contribution of marine fish in the diet of these carnivores was evaluated using carbon, nitrogen and sulphur isotopes in faunal bone collagen, comparing these isotopic signatures between predators and their potential prey.

When the researchers looked at the isotopic signature of the new wolverine, they realized it fell between the values for the two wolverine territories — just what you would expect from a predator that began its life foraging in the Rockies and then switched its diet to the Sierras.

When a wolverine in the Rockies eats a deer that has fed on the local plants, an isotopic signature is passed up the food chain into its hair.

U-M doctoral student Michael Cherney and his adviser, Museum of Paleontology Director Daniel Fisher, say an isotopic signature in 15 tusks from juvenile Siberian woolly mammoths suggests that the weaning age, which is the time when a calf stops nursing, decreased by about three years over a span of roughly 30,000 years leading up to the woolly mammoth's extinction.