Sentences with phrase «carbon isotope composition»

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)

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.

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

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

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.»

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

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.