The Stable Isotopes of Oxygen

The leaf water, which determines the isotopic composition of the O2 generated by photosynthesis and the CO2 generated by autotrophic respiration. 

The soil/groundwater determining the isotopic composition of CO2 generated by heterotrophic respiration. 

In the oceans, the isotopic signature of seawater determines the O2 produced by photosynthesis and the oxygen isotopic composition of Die generated during remineralization of organic material and carbonate. 

(a) changes in the isotopic composition of the hydrological cycle due to, e.g., climate variations and (b) changes in the carbon and oxygen fluxes between the reservoirs therefore can induce changes in the oxygen isotopic composition of atmospheric CO, and Oj. Dynamically, after a perturbation a new atmospheric steady state of the oxygen isotope ratios establishes within a few years in the case of 0/ 0 in CO, and within about 1200 years in 

FIGURE 4 Relationship between the seasonal cycles of CO, and O, in the interior of the Eurasian continent (at Zotino, 60°N, 90°E) within the planetary boundary layer. The left diagram shows the seasonal signal components in 0. induced from the terrestrial and oceanic seasonal sources the right-hand panel shows the modeled relation between the seasonal cycles of O, and CO2 (monthly averages). 

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Calcium carbonate is also the main constituent of the shells of sea animals, which make their shells from elements acquired from the surrounding waters. Now, the degree of fractionation of the oxygen isotopes as well as the formation of mineral carbonates and of animal shells in sea waters are determined on the basis of the temperature-dependent fractionation of the isotopes of oxygen the oxygen isotope composition of these materials reflects, therefore, the temperature at the time of their formation. Thus determining the isotope ratio between the stable isotopes of oxygen... 

Guy RD, Fogel ML, Berry JA (1993) Photo synthetic fractionation of the stable isotopes of oxygen and carbon. Plant Phys 101 37 7... 

Suzuoki T, Epstein S (1976) Hydrogen isotope fractionation between OH-bearing minerals and water. Geochim Cosmochim Acta 40 1229-1240 Swart PK, Bums SJ, Leder 11 (1991) Eractionation of the stable isotopes of oxygen and carbon in carbon dioxide during the reaction of caldte with phosphoric acid as a function of temperature and technique. Chem Geol 86 89-96... 

Garlick G.D. (1969) The stable isotopes of oxygen In Handbook of Geochemistry, V. II-1 (ed. K.H.Wedepohl), Springer-Verlag, Chapter 8B. 

At the present time there are sufficiently reliable data on the distribution of the stable isotopes of oxygen, carbon, and sulfur in Precambrian sedimentary rocks. On the basis of analysis of these data, it is possible to obtain additional information on the geochemical history of the ocean and conditions of sedimentation. 

Elements in nature come in forms called isotopes that differ only in the number of their neutrons. Most isotopes are stable and can be distinguished from their counterparts simply by their masses. Remarkably, isotopes are associated with a few simple and mass-dependent traits that result in a wide range of useful isotopic signals in natural processes. Coupled with the invention of the isotope ratio mass spectrometer in 1940s (McKinney et al., 1950 Nier, 1947) stable isotope signals provide the basis for application of stable isotopes to environmental sciences. Stable isotopes are denoted by their atomic mass such as and for the two stable isotopes of carbon, and 0, and for the stable isotopes of oxygen. Because the heavy isotope is normally rare (e.g., -1.1% for i c, 0.2% for 0, and 0.04% for O), routine measurements of the absolute isotopic concentrations is difficult and not reliable. Alternatively, the ratio, R, of the rare to the abundant isotopes is measured, such as... 

The use of the stable isotopes of oxygen and hydrogen for tracing the origin of salinity is straightforward in the case of river salinization. 

Isotopic exchange reactions of oxygen have been studied ever since water enriched in the stable isotopes of oxygen (O18 and O17) became available in the 1930 s (Lewis and Cornish, 1933 Urey et al., 1936). 

The stable isotopes of oxygen used in paleooceano-graphic reconstructions are and There are about 500 atoms for every atom in the ocean/atmosphere environment. During the 1940s, Harold Urey at the University of Chicago predicted that the ratio in calcite (CaC03) should... 

Over the past 60 years refined techniques of analysis have shown the patterns of distribution of the trace elements in ocean water profiles in all the oceans. These results are summarized by the late Yoshiyuki Nozaki in this volume. Similarly the understanding of the stable isotopes of oxygen, carbon and nitrogen in the oceans have played important roles in deciphering both the ancient temperature history of the oceans and the biological pathways of nutrient elements in the marine system. 

Bibliography of Chemical Reviews, later known as Bibliography of Reviews in Chemistry. Special bibliographies are occasionally published, such as the Bibliography of the Stable Isotopes of Oxygen and O s by D. Samuel and F. Steckel (Pergamon, 1959) which is complete to 1957 and has author and subject indexes. 

This chapter summarizes the techniques that have been developed for the syntheses and configurational analyses of phosphate mono- and diesters that are chiral only by virtue of substitution with the stable isotopes of oxygen O, 99.759% natural abundance O, 0.037% natural abundance and a nuclear spin of and K), 0.204% natural abundance. In addition, a few enzyme systems in which these techniques have been used are described. This approach, which dates back only to 1978, was not the first method to ascertain the stereochemical consequences of enzyme-catalyzed reactions at phosphorus. In 1970, Usher and Eckstein reported the seminal experiment in this field (Usher et al., 1970) the stereochemical course of the hydrolysis of the endo isomer of uridine 2, 3 -cyclic phosphorothioate catalyzed by... 

The best values for the abundances of the stable isotopes of oxygen in air and water are given in Table I. 

A comprehensive bibliography of all research involving the stable isotopes of oxygen has been published by Samuel and Steckel (1959), with a supplement covering subsequent research to the end of 1960 (Samuel and Steckel, 1961). 

Finally, work with the stable isotopes of oxygen and of hydrogen (unlike and N ) is made more difficult by the ever-present problem of isotopic exchange between the solvent, water, and the reactants, products, or intermediates of the reaction. 

It can be seen from the foregoing pages that considerable effort and ingenuity has been applied in developing methods using the stable isotopes of oxygen for the investigation of chemical and biochemical reactions. Techniques of isolation and purification of products have been described as well as a whole variety of methods of analysis, mostly based on mass spectrometry. 

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