Sentences with phrase «isotopic composition from»

CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere.

Therefore, animals that feed on tropical open - environment grasses (or on grass - eating animals) have different isotopic compositions from those feeding on browse, seeds, or fruit from shrubs or trees.

Not exact matches

Dust found in the ice gives a record of what was in the air thousands of years ago, whether from volcanic eruptions or human activity, and the isotopic composition of the hydrogen and oxygen molecules in the snow give a record of the temperature of the earth at the time.

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.

The researchers analysed quartz crystals from Toba, and found a distinct shift in the isotopic composition towards the outer rim of the crystals.

The authors also monitored the isotopic 13C composition of CO2, which serves as a fingerprint of emissions from coal - fired power plants and matched it to that of the local coal.

The hydrogen isotopic composition of lunar water also varies from region to region, much more dramatically than in Earth.

As part of the study, Cherney measured the isotopic composition of tail hairs from a mother - calf pair of African elephants at the Toledo Zoo.

Working with Miller and doctoral student Abraham Padilla at Vanderbilt, Joe Wooden at Stanford University, Axel Schmitt and Rita Economos from UCLA, Ilya Bindeman at the University of Oregon and Brennan Jordan at the University of South Dakota, Carley analyzed about 1,000 zircon crystals for their age and elemental and isotopic compositions.

The combination of geological and taphonomic evidence, the assemblage of small - mammal and avian fossils, and the taxonomic and isotopic compositions of remains from larger mammals indicate that Aramis was predominantly a woodland habitat during Ar.

«During photosynthesis plants bind atmospheric carbon, whose isotopic composition is preserved in resins over millions of years, and from this, we can infer atmospheric oxygen concentrations,» explains Ralf Tappert.

On the basis of anomalous isotopic compositions of oxygen and magnesium, 14 oxide grains from two primitive meteorites (Bishunpur and Semarkona) have been identified as circumstellar condensates.

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.

http://adsabs.harvard.edu/abs/1999GBioC..13..445Q «The isotopic composition of atmospheric methane» Quay et al 1999 (This study suggests that ~ 18 % of atmospheric methane in 1999 is from fossil fuel sources)

Stable isotopic compositions — variants of particular chemical elements — of such remains, recovered from soil and lake sediment, may help us better understand climate change over a long span of time.

Sea ice melt (SIM) also has relatively low salinity (S < 5), but its oxygen isotopic composition is similar to that of seawater, from which it is formed (δ18O ≅ 0 to — 6 ‰).

The UniChem connectivity search function allows users to find not only exact matches of their chemical structure across 60 million related molecules from 21 data sources worldwide, but also identifies «equivalent» structures that have the same atom connectivity while differing in stereochemistry or isotopic composition, or which exist in a different salt form.

Assessing the anthropogenic influence on atmospheric oxidants using the oxygen isotopic composition of sulfate and nitrate from the WAIS - Divide ice core.

Funny how difficult it is for him and his fellow denialati to look at 1) where that carbon came from 2) its isotopic composition 3) the fact that it takes a while for permafrost to melt and oceans to become a source rather than a sink 4) the fact that humans are producing about 2x as much carbon as is going into the atmosphere 5) the remaining CO2 is acidifying the oceans

As discussed by Veizer et al. there is a major discrepancy during the mid-Mesozoic (120 to 220 Ma) between cold low - latitude temperatures deduced from the oxygen isotopic composition (λ 18O) of fossils and high levels of CO2 and net radiative forcing.

[Response: My recollection is that Zachos had the same observation from ODP cores, that surface - dwelling forams were either isotopically heavy or light, never transitional, but bottom - dwellers could be found with transitional isotopic composition.

[5] Linsley et al. (2006) reconstructed sea - surface temperature and sea surface salinity in the southwest Pacific starting circa 1600CE by measuring the oxygen isotopic composition of four Porites coral records from Rarotonga and two from Fiji.

We determined the chemical and isotopic compositions of the liquid CO2 found on Yonaguni IV knoll hydrothermal site, as well as those in hydrothermal fluid venting from the surrounding chimneys.

Consider the facts: the climate system is indicated to have left the natural cycle path; multiple lines of evidence and studies from different fields all point to the human fingerprint on current climate change; the convergence of these evidence lines include ice mass loss, pattern changes, ocean acidification, plant and species migration, isotopic signature of CO2, changes in atmospheric composition, and many others.

(Partisan) description: The authors studied the isotopic composition of carbon (δ13C) and hydrogen (δD) in organic matter found in two sediment cores retrieved from Lake Korttajarvi.

The net rate of CH4 emissions is generally estimated from three approaches: (1) extrapolation from direct flux measurements and observations, (2) process - based modelling (bottom - up approach) and (3) inverse modelling that relies on spatially distributed, temporally continuous observations of concentration, and in some cases isotopic composition in the atmosphere (top - down approach).

Until now, this view was based mainly on reanalysis of ca estimates from the isotopic composition of carbonates in paleosols, the only extensive proxy record to span most of the Phanerozoic.

The hydrogen and carbon isotopic composition of methane from natural gases of various origins

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.

With regard to the former, I seem to recall reading somewhere that the isotopic composition of the carbon in fossil fuels (and limestone used to make cement) differs from the average composition in current sinks and that can be used to look at where the CO2 is coming from.