Sentences with phrase «stable isotope ratios of»

Stable isotope ratios of oxygen reflect water temperatures, with higher δ18O values indicating colder water [6], [9], [12], such as water upwelled from lower depths.

As precipitation moves inland, water with the heavier form of hydrogen falls out first, which creates predictable patterns of the stable isotopes ratios of precipitation across continents.

Not exact matches

Using spectroscopy, stable isotope ratios (carbon, nitrogen and sulphur) were investigated in the collagen of the bones, along with the ratio of strontium to calcium in the bone mineral.

Researchers linked dated graffiti about droughts in a cave in China to physical evidence in the cave of the water shortages, such as changes in ratios of stable isotopes in specific layers of stalagmites

The team found that the degree of nitrogen pollution, which is worsening in urban areas, can be evaluated by analyzing the nitrogen content and the stable isotope ratio in bryophytes.

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.

«It will enable teachers to introduce students to things called stable isotopes, which is great because we're made up of stable isotopes, and that ratio varies depending on what we eat.»

For instance, radiocarbon dating determines the age of biological remains based on the ratio between the carbon isotopes (atoms of the same element with different numbers of neutrons) carbon - 12 and carbon - 14 it holds - this proportion changes as radioactive carbon - 14 breaks down while stable carbon - 12 does not.

Another option is to test fossil teeth for the ratio of stable isotopes present for a given element, such as the ratio of carbon C12 to C13.

One group of students has been drilling modern and fossil teeth to obtain samples that will be analyzed to examine stable carbon and oxygen isotope ratios.

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

It basically says that ringwidth is a function of: age trend + climate signal + endogenous (local) disturbances + exogenous (standwide) disturbances + unexplained variation Basically, this concept also underlies all other dendro proxies, be it maximum latewood density or stable isotope ratios, even though there are variations, e. g. age trend in density data is treated differently from ring width data).

Like the data used right through 0.02 to 66 My, the Freidrich et al collection comprises stable oxygen isotope ratios from the shells of tiny bottom - dwelling, deep - water marine organisms (benthic foraminifera).

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.

All except C - 14 are stable isotopes, meaning you can derive a delta - C - 13 ratio, AND because of the presence O - 18 and O - 16 a delta - O - 18 ratio can be derived as well.

Stable carbon isotope ratios from tree rings record changes in the internal concentration of carbon dioxide and, in the northern Boreal zone, are regarded as a proxy for photosynthetic rate, and therefore summer sunshine.

Early TRL projects focused on establishing long tree - ring records from temperature - sensitive boreal forest locations in North American for studies of global change, using dendrochronologically dated wood, to investigate the value of stable isotope ratios in cellulose as paleo - thermometers and developing the necessary computer software for processing the data.

The ratio of stable isotopes oxygen - 18 and oxygen - 16 in the foraminifera is an indicator of ocean temperature.

For example, extreme values of the ratio of stable isotopes in foraminifera from the eastern Pacific have previously been interpreted as ENSO activity, but modeling suggests that this interpretation may not always be suitable for past climates due to variability caused by other factors.

The size of the carbon injection is estimated from changes in the stable carbon isotope ratio 13C / 12C in sediments and from ocean acidification implied by changes in the ocean depth below which carbonate dissolution occurred.