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Oxygen (chemical symbol O) has three naturally occurring isotopes: 16 O, 17 O, and 18 O, where the 16, 17 and 18 refer to the atomic mass.The most abundant is 16 O, with a small percentage of 18 O and an even smaller percentage of 17 O. Oxygen isotope analysis considers only the ratio of 18 O to 16 O present in a sample.
O, samples enriched with the other stable isotopes can be used for isotope labeling. For example, it was proven that the oxygen released in photosynthesis originates in H 2 O, rather than in the also consumed CO 2, by isotope tracing experiments. The oxygen contained in CO 2 in turn is used to make up the sugars formed by photosynthesis.
The compounds produced using stable isotopes are either specified by the percentage of labeled isotopes (that is, 30% uniformly labeled 13 C glucose contains a mixture that is 30% labeled with 13 carbon isotope and 70% naturally labeled carbon) or by the specifically labeled carbon positions on the compound (that is, 1-13 C glucose which is ...
Paleoclimatologists measure the ratio of oxygen-18 and oxygen-16 in the shells and skeletons of marine organisms to determine the climate millions of years ago (see oxygen isotope ratio cycle). Seawater molecules that contain the lighter isotope , oxygen-16, evaporate at a slightly faster rate than water molecules containing the 12% heavier ...
The isotopic composition of the oxygen in a core can be used to model the temperature history of the ice sheet. Oxygen has three stable isotopes, 16 O, 17 O and 18 O. [66] The ratio between 18 O and 16 O indicates the temperature when the snow fell. [67] Because 16 O is lighter than 18 O, water containing 16
Oxygen isotopic ratios, which may be measured very precisely, yield a unique and distinct signature for each Solar System body. [40] Different oxygen isotopic signatures can indicate the origin of material ejected into space. [41] The Moon's titanium isotope ratio (50 Ti/ 47 Ti) appears close to the Earth's (within 4 ppm).
"The company should see a return to growth in the first half of 2025, following many consecutive quarters of negative comps, as newness and the replacement cycle kicks in, especially for products ...
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.