Oxygen isotopes, atmospheric

The conclusions of Hurt s study of year-by-year oxygen isotope ratios in 72 years of S. gigantea are thus supportive of the conclusions of the CIAP study [49] that solar variations influence the abundances of many kinds of chemical species in the stratosphere, and therefore influence the.amount of solar energy they absorb and re-radiate to earth, and therefore influence the surface temperature of the earth and especially the surface temperatures of the oceans. It is the surface temperature of the oceans which produces the phenomena we have discussed the isotope ratio variations in rain and hence in tree rings, the isotope ratio variations in the Greenland ice cap, in the organic carbon and uranium concentrations in sea cores, and furthermore variations of the sea surface temperature produces variations in the carbon-14 to carbon-12 ratio fractionation at the sea air interface and hence in the carbon-14 content of atmospheric carbon dioxide and hence in the carbon-14 content of tree rings. 

Fig. 14.4 Oxygen isotopic composition of atmospheric species measured to date (After Thiemens, M., Ann. Rev. Earth Planet. Sci. 34, 217 (2006)). For these data, m, Equation 14.31 is approximately (0.7 < m < 0.9) indicating for these materials the fractionation is better described as anomalous rather than mass independent ...

Thiemens MH, Heidenreich JE (1983) The mass independent fractionation of oxygen a novel isotope effect and its possible cosmochemical implications. Science 219 1073-1075 Thiemens MH, Jackson TL, Brenninkmeijer CAM (1995) Observation of a mass-independent oxygen isotopic composition in terrestrial stratospheric COj, the link to ozone chemisdy, and the possible occurrence in the Martian atmosphere. Geophys Res Lett 22 255-257 Timmes FX, Woosley SE, Weaver TA(1995) Galactic chemical evolution hydrogen through zinc. Astrophys J Suppl 98 617-658... 

Mass-independent isotopic fractionations are widespread in the earth s atmosphere and have been observed in O3, CO2, N2O, and CO, which are all linked to reactions involving stratospheric ozone (Thiemens 1999). For oxygen, this is a characteristic marker in the atmosphere (see Sect. 3.9). These processes probably also play a role in the atmosphere of Mars and in the pre-solar nebula (Thiemens 1999). Oxygen isotope measurements in meteorites demonstrate that the effect is of significant importance in the formation of the solar system (Clayton et al. 1973a) (Sect. 3.1). 

The 8 N- and 8 0-values of atmospheric N2O today, range from 6.4 to 7.0%c and 43 to 45.5%c (Sowers 2001). Terrestrial emissions have generally lower 8-values than marine sources. The 8 N and 8 0-values of stratospheric N2O gradually increase with altitude due to preferential photodissociation of the lighter isotopes (Rahn and Wahlen 1997). Oxygen isotope values of atmospheric nitrous oxide exhibit a mass-independent component (Cliff and Thiemens 1997 Clifif et al. 1999), which increases with altitude and distance from the source. The responsible process has not been discovered so far. First isotope measurements of N2O from the Vostok ice core by Sowers (2001) indicate large and 0 variations with time (8 N from 10 to 25%c and 8 0 from 30 to 50%c), which have been interpreted to result from in situ N2O production via nitrification. 

Sowers et al. (1993) and Bender et al. (1994) showed that it is possible to con-strnct an oxygen isotope cnrve similar to that derived from deep-sea foraminifera from molecnlar O2 trapped in ice. These anthors argued that 5 0(atm) can serve as a proxy for ice volume jnst as 5 0-valnes in foraminifera. The isotope signal of atmospheric oxygen can be converted from sea water via photosynthetic marine organisms according to the following scheme... 

Figure 3.49 summarizes the oxygen isotope curve for the last 65 Ma. The most pronounced warming trend is expressed by a 1.5%o decrease in 8 0 and occurred early in the Cenozoic from 59 to 52 Ma, with a peak in Early Eocene. Coinciding with this event is a brief negative carbon isotope excursion, explained as a massive release of methane into the atmosphere (Norris and Rohl 1999). These authors used high resolution analysis of sedimentary cores to show that two thirds of the carbon shift occurred just in a few thousand years, indicating a catastrophic release of carbon from methane clathrates into the ocean and atmosphere. 

Bottinga Y, Craig H (1969) Oxygen isotope fractionation between CO2 and water and the isotopic composition of marine atmospheric CO2. Earth Planet Sci Lett 5 285-295 Bottinga Y, Javoy M (1973) Comments on oxygen isotope geothermometry. Earth Planet Sd Lett 20 250-265... 

Brand W (2002) Mass spectrometer hardware for analyzing stable isotope ratios. In P de Groot (ed.) Handbook of stable isotope analytical techniques. Elsevier, Amsterdam Brandriss ME, O Neil JR, Edlund MB, Stoermer EF (1998) Oxygen isotope fractionation between diatomaceous silica and water. Geochim Cosmochim Acta 62 1119-1125 Bremner JM, Keeney DR (1966) Determination and isotope ratio analysis of different forms of nitrogen in soils. III. Soil Sci Soc Am Proc 30 577-582 Brenninkmeijer CAM (1993) Measurement of the abundance of CO in the atmosphere and the and 0/ 0 ratio of atmospheric CO with applications in New Zealand and Australia. J Geophys Res 98 10595-10614... 

Clayton RN, Goldsmith JR, Karel KJ, Mayeda TK, Newton RP (1975) Limits on the effect of pressure in isotopic fractionation. Geochim Cosmochim Acta 39 1197-1201 Clayton RN, Onuma N, Grossman C, Mayeda TK (1977) Distribution of the presolar component in Allende and other carbonaceous chondrites. Earth Planet Sd Lett 34 209-224 Clayton RN, Goldsmith JR, Mayeda TK (1989) Oxygen isotope fractionation in quartz, albite, anorthite and caldte. Geochim Cosmochim Acta 53 725-733 Cliff SS, Thiemens MH (1997) The 0/ 0 and 0/ 0 ratios in atmospheric nitrous oxide a mass independent anomaly. Science 278 1774-1776 Cliff SS, Brenninkmeijer CAM, Thiemens MH (1999) First measurement of the 0/ 0 and ratios in stratospheric nitrous oxide a mass-independent anomaly. J Geophys Res 104 16171-16175... 

Ann Rev Plant Physiol Plant Mol Biol 40 503-537 Farquhar GD, et al. (1993) Vegetation effects on the isotope composition of oxygen in atmospheric CO2. Nature 363 439 43... 

Farquhar J, Thiemens MH (2000) The oxygen cycle of the Martian atmosphere-regoUth system secondary phases in Nakhla and Lafayette. J Geophys Res 105 11991-11998 Farquhar J, Chacko T, Ellis DJ (1996) Preservation of oxygen isotopic compositions in granuhtes from Northwestern Canada and Enderby Land, Antarctica implications for high-temperature isotopic thermometry. Contr Miner Petrol 125 213-224 Farquhar J, Thiemens MH, Jackson T (1998) Atmosphere-surface interactions on Mars mea-... 

Kroopnick P (1985) The distribution of C of IC02 in the world oceans. Deep Sea Res 32 57-84 Kroopnick P, Craig H (1972) Atmospheric oxygen isotopic composition and solubility fractionation, Science 175 54-55... 

Longinelli A (1984) Oxygen isotopes in mammal bone phosphate a new tool for paleohydrological and paleoclimatological research . Geochim Cosmochim Acta 48 385-390 Longinelli A, Bartelloni M (1978) Atmospheric pollution in Venice, Italy, as indicated by isotopic analyses. Water Air Soil Poll 10 335-341... 

Stein LY, Yung YL (2003) Production, isotopic composition, and atmospheric fate of biologically produced nitrous oxide. Ann Rev Earth Planet Sci 31 329-356 Stem LA, Chamberlain CP, Reynolds RC, Johnson CD (1997) Oxygen isotope evidence of climate change from pedogenic clay minerals in the Himalayan molasse. Geochim Cosmochim Acta 61 731-744... 

The oxygen isotope ratio of ice cores is mostly controlled by a different influence, however the temperature of the clouds from which the snow fell. When water vapour condenses to water or ice, isotope sifting occurs just as it does during evaporation - but in reverse the lighter isotope stays behind. The last precipitation to leave a cloud - the snow that falls over the poles - is therefore enriched in O. The amount of enrichment turns out to depend on how cold it is over the ice sheet. So ice-core isotope records show us how atmospheric temperatures have changed over time. 

Mass Spectrometry. Mass spectrometric detection was used in early laboratory studies of H02 (103, 104) and has also been used in more recent investigations (105). The H02 peak at the mass-to-charge ratio mle = 33 is useful in laboratory identification and quantification, but in the atmosphere, most likely multiple species will interfere because of, for example, fragmentation of hydrocarbons, hydrogen peroxide, or oxygen isotopes. 

---