Sentences with phrase «carbon isotopes»
Carbon isotopes refer to the different forms or types of carbon atoms found in the environment. Carbon has three isotopes: carbon-12, carbon-13, and carbon-14. These isotopes have slightly different numbers of neutrons in their nuclei, resulting in different atomic weights. Studying carbon isotopes helps scientists understand various processes like carbon cycling, climate change, and tracking the movement of carbon in living organisms and the environment. Full definition
A study published last month in Quaternary International analyzed the ratio of carbon isotopes in Gigantopithecus teeth, and found that the 10 - foot - tall apes ate mostly forest fruit.
sciencemag.org
Comparison of stable carbon isotope ratios in the whole wood, cellulose and lignin of oak tree - rings Dr. Ron Towner from the Laboratory of Tree - Ring Research at the University of Arizona explains the principles behind dendrochronology and why this dating
Change of diet of the Greenland Vikings determined from stable carbon isotope analysis and 14C dating of their bones.
Cerling3 used carbon isotope ratios in soil carbonate minerals to constrain atmospheric PCo2m portions of the Mesozoic and Cenozoic eras.
Based on carbon isotope analyses the methane is of biogenic origin.
In a paper published online this week by the journal Quaternary International, 26 members of the working group point roughly to 1950 as the starting point, indicated by a variety of markers, including the global spread of carbon isotopes from nuclear weapon detonations starting in 1945 and the mass production and disposal of plastics.
Onset of carbon isotope excursion at the Paleocene - Eocene thermal maximum took millennia, not 13 years.
By measuring carbon isotope ratios in the nodules, the researchers found that during each 1,500 - year carbon release, the ratio of carbon - 13 to carbon - 12 in the atmosphere declined, indicating two large releases of carbon dioxide or methane, both greenhouse gases from plant material.
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)
Much of the work is based on carbon isotope studies.
Much of the work is based on carbon isotope studies.
The data also include carbon isotope values for the methane concentrations.
The metabolic processes of modern methane - producing bacteria tend to preferentially use lighter carbon isotopes such as carbon - 12.
Oxygen isotopes are used to distinguish water sources such as groundwater or rainfall, while carbon isotopes reveal how efficiently trees are using that water — a calculation of photosynthesis versus water loss.
For myself, I draw the line at carbon isotope studies and anything older than the last glacial period in paleoclimate (with a couple of exceptions).
Evidence from carbon isotope records from both soil carbonates [18]--[20] and biomarkers (n - alkanes) extracted from deep - sea sediments [21] provide clear evidence of a progressive vegetation shift from C3 (∼ trees and shrubs) to C4 (∼ tropical grasses) plants during the Plio - Pleistocene.
This scenario is consistent with altered PETM circulation patterns inferred from benthic carbon isotope data and the intensity of deep - sea carbonate dissolution in the South Atlantic.
Because cells incorporate carbon from the atmosphere into their DNA as they divide, the proportion of carbon - 14 to the more stable carbon isotope carbon - 12 acts as a time stamp for when a cell was born.
There's the 13C / 12C carbon isotope ratios from tree rings and high resolution ice cores that show a clear downward trend starting early in the 19th century consistent with the rise in atmospheric CO2 starting about the same time which some consider indicative of an anthropogenic contribution by that time period.
They exploit the fact that the PETM carbon isotope curve recorded in land sediments is consistently larger that in marine sediments.
Subsequent labeling experiments using the stable carbon isotope 13C demonstrated that wild - type L. japonicus hosts indeed directly provide the fungus with the required lipids.
The only previously known radioactive carbon isotope at the time was carbon - 11, which had a half - life of only 21 minutes (half the isotope's radioactivity will decay in that time).
Next, she sent the purified genetic material to the Lawrence Livermore National Laboratory in California, where it was reduced to pure carbon pellets and split into different carbon isotopes by weight in a particle accelerator, allowing the researchers to calculate the ratio between carbon - 12 and carbon - 14.
Studies of the common mineral goethite (α - FeOOH) have shown that it contains small quantities of a carbonate component (Fe (CO3) OH), the concentration and carbon isotope content of which preserves a record of ambient PCo2at the time of formation4 — 7.
His 1982 paper «On the relationship between carbon isotope discrimination and the intercellular carbon dioxide concentration in leaves» passed its 1,
The carbon budget for the 1980s was analysed not only from bottom - up emissions estimates, but also from a top - down approach including carbon isotopes.
Chemist Hans Suess put this to the test by examining carbon isotopes in trees.
To date our understanding of this process comes from benthic carbon isotope and CaCO3 burial records.
Quantitative trait loci for water - use efficiency in barley (Hordeum vulgare L.) measured by carbon isotope discrimination under rain - fed conditions on the Canadian Prairies, Theoretical and Applied Genetics 125: 71 — 90.
Modeled carbon isotope curves (CIEs) for 3 different emissions sources over 4 different emission timeframes.
Core PS51 / 038 -3: MIS 6 and MIS 5 (5e) have mainly been identified by oxygen and carbon isotope stratigraphy, paleomagnetostratigraphy, and abundances of planktic foraminifers and coarse fraction (Supplementary Fig. 3) 56.
The cause of the Paleocene - Eocene thermal maximum carbon isotope excursion remains speculative, primarily due to uncertainties in the timing and duration of the Paleocene - Eocene thermal maximum.
After around 12,000 years, only stable carbon isotopes remain.
An international team of researchers studying globally declining shark populations report today that they used carbon isotopes as biochemical markers in shark muscle tissue...
The fractionation of carbon isotopes during photosynthesis causes the carbon products used to synthesize leaf tissue to be relatively depleted in the heavier 13C isotope [Farquhar et al., 1989].
It was claimed the portion in the atmosphere from combustion of fossil fuels was known from the ratio of carbon isotopes C13 / C12.