Sentences with phrase «isotope composition of»

If you want a new theory, make sure it matches the observations of methane as well and also accounts for the isotope composition of both in ice cores.

«We looked at ice cores and tropical sponge records, which give us reliable proxies for the carbon isotope composition of atmospheric carbon dioxide.

Here, we present a record of Holocene glacial ice discharge, derived from the oxygen isotope composition of marine diatoms from Palmer Deep along the west Antarctic Peninsula continental margin.

«It is based on a sophisticated statistical analysis of the isotope composition of sediment in old French wines.

The boron isotope composition of foraminifera provides a powerful tracer for CO2 change over geological time.

«As an animal eats and drinks, the local strontium isotope composition of the water, plants and animals consumed is recorded in its skeletal tissues.»

The researchers looked at the nitrogen stable isotope composition of different members of the food web at suburban ponds.

The meteorites represent Earth's «building blocks» and, thus, yield the original uranium isotope composition of Earth as a whole, and also the undisturbed mantle.

A Cologne working group involving Prof. Carsten Münker and Dr. Elis Hoffmann and their student Sebastian Viehmann (working with Prof. Michael Bau from the Jacobs University Bremen) have managed for the first time to determine the isotope composition of the rare trace elements Hafnium and Neodymium in 2.7 - billion - year - old seawater by using high purity chemical sediments from Temagami Banded Iron Formation (Canada) as an archive.

The isotope composition of water vapor, i.e. the ratio of light and heavy water molecules, provides insight into underlying mechanisms.

For the first time, the researchers have proved that both the worldwide measurement network NDACC with its ground stations and modern weather satellites provide reliable global data for the isotope composition of tropospheric water vapor.

The thorough mixing of this atmosphere explains the identical isotope composition of Earth and Moon, Wang said.

The examination of the isotope composition of individual amino acids in the collagen shows that the bears lived on a strictly vegan diet.

Otolith O and C Stable Isotope Compositions of Southern Bluefin Tuna Thunnus maccoyii (Pisces: Scombridae) as Possible Environmental and Physiological Indicators.

By studying the carbon isotope compositions of barley plants and their relationship with water - use efficiency, the researchers developed tools that plant breeders can use to improve selection efficiency for more water - efficient varieties.

Not exact matches

«Since this correlation of geochemistry and seismology now holds from helium isotopes in this work to the compositions we examined in 2012, it appears that overall hotspot geochemical variations will need to be re-examined from the perspective of buoyancy,» Konter concluded.

The composition of these ice cores, especially the presence of hydrogen and oxygen isotopes, provides a picture of the climate at the time.

The ratio of oxygen isotopes in seawater depends on the water temperature; the value of this ratio at any point in evolutionary time is «frozen» into the chemical composition of certain marine fossils.

Crowley explains that strontium is an effective isotope to use for this kind of geological tracking because it is so common and varies among rock types with differing chemical compositions or ages.

By analyzing the composition and concentrations of argon and neon isotopes trapped within the minerals collected from modern - day Papua New Guinea, Baldwin and Das identified the source of the mineral - bound gases.

But more accurate measurements of oxygen isotopes published in 2016 only confirmed that the isotopic compositions are not distinguishable.

For this study, the team set out to investigate the timing of supernova dust formation by measuring isotopes — versions of elements with the same number of protons but different numbers of neutrons — in rare presolar silicon carbide grains with compositions indicating that they formed in type II supernovae.

They then performed chemical extraction on the samples to analyze the sulfur isotope compositions in order to estimate the chemistry of the global ocean.

Unlike previous methods, the clumped isotope paleothermometer technique does not rely on assumptions about the isotopic composition of seawater.

Both events were accompanied by warming episodes the U-M-led team found by analyzing the chemical composition of fossil shells using a recently developed technique called the carbonate clumped isotope paleothermometer.

They also used satellite precipitation data to «backsolve» the brine's origins using sodium concentrations, oxygen and hydrogen isotopes, as the isotopic composition of water reflects the condensation temperature and precipitation rate over time.

To do so, they analysed the fatty - acid patterns and the composition of stable isotopes in the polar cod's muscle and other tissues.

The second method involved measuring the spread of air with water molecules with different isotope composition in the layers with the compressed snow.

The results also have an important consequence for rock compositions — notably the ratios of certain isotopes, Natland says.

The difference between using DNA analysis and isotope tracking is a variation on the nature versus nurture debate: DNA records an organism's genetic inheritance, and isotopes reflect the composition of the environment in which it grows.

Recent measurements of the ratio of two isotopes of hydrogen suggest Enceladus's composition is strangely comet - like.

The information about oxygen concentration comes from the isotopic composition of carbon or rather from the ratio between the stable carbon isotopes 12C and 13C.

«We therefore had to use a different method, so we measured the composition of carbon isotopes — the ratio of protein and mineral content — in the fossilized sloth bones,» explains Bocherens, and he continues, «Our measurements show that Megatherium lived on an exclusively vegetarian diet.»

Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.

Tungsten contains one isotope of mass 182 that is created when an isotope of the element hafnium undergoes radioactive decay, meaning its elemental composition changes as it gives off radiation.

Building Atoms, Ions, and Isotopes HD Lite - free With the Building Atoms, Ions, and Isotopes app, explore the composition of the elements.

Because different isotopes of water freeze at different rates at different temperatures, ice composition depends on the temperature at which it formed.

Isotope ratios are based on present day composition of sea water.

Considering the differences in FA composition and stable isotope values, we suggest that females from the North - West and South - East could ingest a higher proportion of avian prey.

There are at least a dozen other proxies: foram mineral composition, varves, cave deposits, carbon and Be isotopes (indicators of solar activity), ice cores....

Here, we calculate tightly constrained estimates of ca using a universal equation for leaf gas exchange, with key variables obtained directly from the carbon isotope composition and stomatal anatomy of fossil leaves.

Our proxies, including oxygen isotopes and annual ring widths (MAT = — 0.5 ± 1.9 °C), coexistence of paleovegetation (MAT = — 0.4 ± 4.1 °C), and bacterial tetraether composition in paleosols (MAT = — 0.6 ± 5.0 °C), yield estimates that are statistically indistinguishable.

Mean values ± standard deviation of methane concentrations (as milligrams of CH4 L - 1) and carbon isotope composition in methane in shallow groundwater δ13C - CH4 sorted by aquifers and proximity to gas wells (active vs. nonactive)

The scientists initially determined the rate of the LIS collapse using «radiocarbon dates of organic matter and marine shells, cosmogenic dates from the surface of boulders, and the composition of isotopes in marine sediment cores», but then the scientists also used a state - of - the art climate model to see if its results would bear out the paleoclimate data.

The methane produced by the burning of biomass, like wood, contains more of the heavier isotope (carbon - 13) relative to the lighter isotope (carbon - 12), than methane which is produced in wetlands,» explains Professor Thomas Blunier, Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.The researchers have measured the isotopic composition of the methane in ice cores that are drilled up from the Greenland ice cap at the NEEM project in northwestern Greenland.

• Chemical Data Analysis • Literature reviewing • Experimental research designing • Element Analysis • Chemical Equating • Metal combustion examination • Study of isolated isotopes of various metals • Element density and composition scrutiny