Sentences with phrase «measuring isotope ratios»

By measuring isotope ratios in shells from some of these snails from as long ago as 1918, the researchers have demonstrated that they could reconstruct the subseasonal rainfall rate of past monsoon seasons.

By measuring isotope ratios in B. kiplingi «s tissue and plugging this data into a dietary model, Christopher Meehan of the University of Arizona in Tucson determined that protein - rich nodules called Beltian bodies, found on the leaves of some plants, make up 90 per cent of its diet (Current Biology, DOI: 10.1016 / j.cub.2009.08.043).

The scientists measured the isotope ratios in three ice cores from across East Antarctica, each of which dates back to at least 340,000 years ago.

«If one measured the isotope ratios, those would have characteristics of Earth organisms,» Conley says.

You could actually do things like measure the isotope ratios and the Ar / N2 ratio of tree rings of trees where you have a thermometer record and then have a look at tree rings of the same species in the past.

Not exact matches

The new Schmidt grant will allow the Scripps team to chip away at a years - long backlog of air samples to measure changes in the ratio of carbon isotopes, which provides information about manmade sources of CO2.

They then compared the oxygen isotope ratio in Yonderup dripwater with that predicted by a model (which simulated the dripwater δ18O based on measurements of rainwater δ18O), as well as that measured at a different cave in the region.

Grind a few flecks of calcite off a cave painting, measure the ratio of uranium and thorium isotopes, and you can read out the age of the calcite.

«We took a sample every 10 metres,» says Louis Honegger, a researcher at UNIGE, «measuring the ratio between 13C (heavy carbon stable isotope) and 12C (light carbon stable isotope).

Barrick and Showers measured the relative ratios of the isotopes oxygen - 16 and oxygen - 18 in the phosphate from 54 samples of a near - complete T. rex skeleton.

Then they measured those two isotopes in the apes» urine to see how the ratio changed over time.

In fact food scientists can tell or could tell if allegedly pure maple syrup had been doctored with additional sweeteners by measuring the carbon - isotope ratios, but what's now an environmentally changed isotope ratio could make it harder to see if maple syrup or other foods are being altered before being sold.

By applying uranium - thorium dating to the corals and measuring ratios of oxygen isotopes in their skeletons, her lab reconstructed ocean temperatures for much of the last 7000 years.

When they compared the isotope predictions with the weather - station data, the measured ratios in northern latitudes tended to be higher than expected, the team reports tomorrow in Nature.

The team also measured the carbon isotope ratios in the turkey bones to reconstruct their diets.

Karlos Muehlenbachs of the University of Alberta measured the ratio of oxygen isotopes in the oldest rocks known on Earth, which formed 3.96 billion years ago.

Environmental scientist Suzanna Richter and plant physiological ecologist Brent Helliker, both at the University of Pennsylvania, measured the ratio of two isotopes of oxygen — rarer oxygen - 18 and more common oxygen - 16 — in samples of wood.

In addition, Valley and his group measured oxygen isotope ratios, which give evidence of early homogenization and later cooling of the Earth.

The authors used highly sensitive instruments mounted on towers as well as soil chambers to continuously measure the ratio of two isotopes of carbon, which differ by their atomic mass.

Because photosynthesis, but not respiration, prefers the lighter carbon isotope, the researchers could detect the separate carbon flows from each of the two processes by measuring the ratio of the two carbon isotopes.

By measuring the ratio of carbon isotopes in the samples the team collected, they were able to tell how much carbon was from fossil fuel combustion.

It is important to measure the ratio of the two isotopes.

«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.»

It measures the ratios of several different isotopes that are important for understanding the long - term history of the atmosphere.

About six years ago, researchers began measuring the abundance of these isotopes and determined their ratios in the natural world.

Curiosity will grind up Gale crater minerals and deliver them to SAM so the isotope ratios can be measured, giving a glimpse at the Martian atmosphere from long ago, perhaps when it could have supported life.

Now, Hubertus Fischer of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, and colleagues have measured carbon isotope ratios in methane from the whole of the last glacial - interglacial transition (between 20,000 and 10,000 years before present) by analysing ice - cores.

Temperature is often the easiest thing to measure, thanks to the oxygen isotope ratio correlating with air temperature, but it is not necessarily the most relevant.

For decades, scientists studying climate change have measured the oxygen isotope ratio in tree - ring cellulose to determine the ambient temperature and relative humidity of past climates.

The group highlighted the added value of measuring paired coral strontium / calcium ratios (Sr / Ca) and oxygen isotope ratios (δ18O), two key proxies for sea surface temperature that are often referred to as paleothermometers (δ18O also reflects sea surface salinity).

The temperature is measured by the the oxygen isotope ratio, which we recently learned is the temperature of the leaves, and the leaves tend to keep a constant temperature.

By dating the shells and measuring their ratio of boron isotopes, they were able to estimate how much CO2 was in the air when the plankton were alive.

However, when measuring the isotopes in nitrate alone, the team found an unexpected imbalance in the ratio of heavy nitrogen and oxygen.

The scientists collected seawater from various depths and measured the ratios of certain oxygen and nitrogen isotopes in the samples.

Strontium isotope ratios can be measured at the delta ppm level using a medium to high resolution magnetic sector mass spectrometer with multiple fixed collectors and either thermal ionization or inductively coupled plasma as an ion source.

13 - C / 12 - C isotope mass balance calculations show that IPCC's atmospheric residence time of 50 - 200 years make the atmosphere too light (50 % of its current CO2 mass) to fit its measured 13 - C / 12 - C isotope ratio.

Because the different isotope ratios for the two kinds of plants propagate through the food chain, it is possible determine if the principal diet of a human or other animal consists primarily of C3 plants or C4 plants by measuring the isotopic signature of their collagen and other tissues.