Sentences with phrase «isotope composition in»
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)
http://www.pnas.org/
The second method involved measuring the spread of air with water molecules with different isotope composition in the layers with the compressed snow.
They then performed chemical extraction on the samples to analyze the sulfur isotope compositions in order to estimate the chemistry of the global ocean.
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.
Both the eggshells and the embryo bones were analyzed in order to determine their oxygen isotope composition.
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.
The examination of the isotope composition of individual amino acids in the collagen shows that the bears lived on a strictly vegan diet.
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.
To do so, they analysed the fatty - acid patterns and the composition of stable isotopes in the polar cod's muscle and other tissues.
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 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.
«As an animal eats and drinks, the local strontium isotope composition of the water, plants and animals consumed is recorded in its skeletal tissues.»
«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 is based on a sophisticated statistical analysis of the isotope composition of sediment in old French wines.
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.
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.
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.
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.