Sentences with phrase «isotope ratios show»

There is no doubt that the CO2 is from fossil sources, as isotope ratios show that the carbon has been less exposed to galactic cosmic rays (GCRs).

«We found that lithium isotope ratios show a... peak around this time, and we can model that as being due to a decrease in silicate weathering during this cooling time period,» Pogge von Strandmann said.

Their carbon - isotope ratio shows that all of a sudden there was a lot more light carbon - 12 — the kind that living organisms favor, the kind in seafloor hydrates — in the water around the forams.

3b) Analysis of carbon - isotope ratios shows that the additional carbon in the atmosphere is fossil carbon.

Not exact matches

More recently, researchers have shown that the ratio of isotopes in feathers can provide a rough guide to where a bird has been feeding, because the feather ratios mirror those of food sources.

Knowing that strontium derived from land shows a slightly higher ratio of strontium 87 than strontium derived from hydrothermal circulation, the scientists compared isotopes in each type of barite.

Analysis of isotope ratios in hair samples showed how much of the bears» diets came from human food.

«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.»

Ancient sediments that once resided on a lake bed and the ocean floor show sulfur isotope ratios unlike those found in other samples from the same time, calling into question accepted ideas about when the Earth's atmosphere began to contain oxygen, according to researchers from the U.S., Canada and Japan.

u «The moon rocks, however, showed [oxygen isotope] ratios markedly similar to those of rocks from Earth.

Investigation of ash sediments from recent Mt. Pinatubo eruptions and other major volcanic events show a signature of mass independent isotope ratios of sulfur, while sediment from minor eruption does not.

Surprisingly, both samples» sulfur isotope ratios fall in the mass - dependent fractionation range and do not show the signal of an oxygenless atmosphere.

Initial SAM results show an increase of 5 percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed.

Minerals and isotopes in these zircons show that water and granite were also present.38 The extremely low ratio of 13C to 12C suggests that all these carbon isotopes were not originally present.

The thread here http://www.realclimate.org/index.php?p=87 that makes that claim does not show that quantitatively (e.g. does not take into account natural variations in carbon isotope ratios).

Here's a link showing one way carbon isotope ratios can vary naturally.

Isotope ratios of carbon are one very strong line of evidence to show that the increase in CO2 comes from the burning of fossil fuels.

Tests showed the ratio of the nitrogen - 15 isotope to the more common nitrogen - 14 isotope had changed from pre-industrial times to the present.

Laboratory PhD Matteus Lindgren is showing some hardware of the MAT 253 Isotope Ratio Mass Spectrometer to Assoc. prof, Giuliana Panieri, laboratory manager Trine Dahl and Director of CAGE Jürgen Mienert.

This analytical document shows that stable isotope ratios can be used to monitor changes in the character of precipitation in response to periodic variability or changes in climate.

Thus even if more C4 plants are grown, that changes the amounts of 12CO2 which is absorbed vs. 13CO2, but as long as the O2 levels show that the biosphere is a net sink for CO2 (whatever the type), more 12CO2 leaves the atmosphere than 13CO2, compared to the atmospheric isotope ratio.

Plotting the isotope ratio's will show the temperature history, but not calibrated to temperature.

Also, the carbon isotope ratios are supposed to show that the increase is anthropogenic (from using burning «old carbon», less C14 or deduced by C13 / C12 ratios, etc..)

Mona Loa dCO2 / dT (Fraction of emission «showing up» in atmosphere) Also: Spencer Part2: More CO2 Peculiarities — The C13 / C12 Isotope Ratio

There are a multitude number of pieces of evidence for this, stemming from mass balance arguments, changes in isotopes, O2 / N2 ratios, observed changes in carbon in other sources (acting as a sink), paleo - sensitivity studies showing that CO2 is a relatively slow and weak feedback (~ 10 ppm / C), etc..

Paleo temperatures from oxygen isotope ratios from the greenland ice cores show that a temperature increase of 0.7 °C will not bring the current temperature up to the level of the Medieval Warm Period let alone the Roman optimum and the MInoan Warm period which were both warmer than the medieval warm period.

Carbon and oxygen isotope ratios both shift at the same boundary; the former shows disruption of the carbon cycle, while the latter shows an abrupt warming of about 6 degrees.

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.