Oxygen isotope exchange between carbonic acid, bicarbonate, carbonate, and water: A re-examination of the data of McCrea (1950) and an expression for the overall partitioning of oxygen isotopes between the carbonate species and water

Usdowski, E.; Hoefs, Jochen

doi:10.1016/0016-7037(93)90159-t

Cited by 105 publications

(77 citation statements)

References 11 publications

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“…Similarly, a recent re-examination of the oxygen isotope data of McCrea on inorganic calcite precipitation also linked oxygen isotopic fractionation to carbonate species equilibrium (Usdowski and Hoefs, 1993). Based on laboratory measurements of oxygen isotope exchange between dissolved carbonate and water at different pH values, Usdowski et al (1991) demonstrated that oxygen fractionation factors vary as a function of the major carbonate component equilibrium.…”

Section: ϫmentioning

confidence: 98%

A study of oxygen isotopic fractionation during bio-induced calcite precipitation in eutrophic Baldeggersee, Switzerland

Teranes

McKenzie

Bernasconi

et al. 1999

Geochimica et Cosmochimica Acta

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Abstract-In order to better understand environmental factors controlling oxygen isotope shifts in autochthonous lacustrine carbonate sequences, we undertook an extensive one-year study (March, 1995 to February, 1996 of water-column chemistry and daily sediment trap material from a small lake in Central Switzerland. Comparisons between calculated equilibrium isotope values, using the fractionation equation of Friedman and O'Neil (1977) and measured oxygen isotope ratios of calcite in the sediment-traps reveal that oxygen isotopic values of autochthonous calcite (␦ 18 O) are in isotopic equilibrium with ambient water during most of the spring and summer, when the majority of the calcite precipitates. In contrast, small amounts of calcite precipitated in early-spring and again in late-autumn are isotopically depleted in 18 O relative to the calculated equilibrium values, by as much as 0.8‰. This seasonally occurring apparent isotopic nonequilibrium is associated with times of high phosphorous concentrations, elevated pH (ϳ8.6) and increased [CO 3 2Ϫ ] (ϳ50 mol/l) in the surface waters. The resulting weighted average ␦ 18 O value for the studied period is Ϫ9.6‰, compared with a calculated equilibrium ␦ 18 O value of Ϫ9.4‰. These data convincingly demonstrate that ␦ 18 O of calcite are, for the most part, a very reliable proxy for temperature and ␦ 18 O of the water.

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Section: ϫmentioning

confidence: 98%

A study of oxygen isotopic fractionation during bio-induced calcite precipitation in eutrophic Baldeggersee, Switzerland

Teranes

McKenzie

Bernasconi

et al. 1999

Geochimica et Cosmochimica Acta

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“…The pH dependent oxygen isotope values of the aragonite are calculated as if all the DIC in solution at that time were made into solid CaCO 3 using the equations of Usdowski et al (1993) as discussed by Zeebe (1999) and then converted to the PDB scale. The fractionation factors are listed in Figure 8.…”

Section: A Numerical Model Of Deep-sea Coral Calcificationmentioning

confidence: 99%

Stable isotopes in deep-sea corals and a new mechanism for “vital effects”

Adkins

Boyle

Curry

et al. 2003

Geochimica et Cosmochimica Acta

367

395

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Offsets from isotopic equilibrium in biogenic carbonates have complicated paleoclimate reconstructions for decades. We use a new archive of climate, deep-sea corals, to evaluate the calcification processes, independent of photosynthesis, that contribute to these offsets. Carbon and oxygen stable isotope data from six modern deepsea corals show strong linear trends between δ 13 C and δ 18 O. Slopes of these trends between samples are similar and range between 2.1-2.6 for ∆δ 13 C/∆δ 18 O. Linear trends intersect isotopic equilibrium for δ 18 O and are slightly depleted for δ 13 C. Variations in the isotopic ratios are strongly correlated with the density banding structure. Isotopically depleted aragonite is associated with light, fast precipitating bands, while isotopically enriched points correspond to slowly accumulating less dense aragonite. The densest, white band at the trabecular center is furthest from isotopic equilibrium for both carbon and oxygen. Data from this region fall off the linear trend between δ 18 O and δ 13 C. This deviation, where δ 13 C is anomalously heavy for the δ 18 O, does not support "vital effect" mechanisms that call upon kinetic fractionation to explain offsets from isotopic equilibrium. We propose a new mechanism for "vital effects" in biogenic carbonates that is based on a thermodynamic response to a biologically induced pH gradient in the calcifying region.

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“…While the inorganic CO 2 chemistry and isotope fractionation of carbon in the CO 2 -H 2 O-CaCO 3 system has been rather well known for quite some time now (for summary, see Millero 1995;Zhang et al 1995;, this is not the case for oxygen (Usdowski & Hoefs 1993;Zeebe 1999;Zeebe 2005b) and less so for boron. In the following, the inorganic chemistry and stable isotope fractionation of dissolved boron in aqueous solution is used as an example to illustrate the steps taken in the process of understanding the Fig.…”

Section: Stable Isotope Fractionationmentioning

confidence: 99%

Vital effects and beyond: a modelling perspective on developing palaeoceanographical proxy relationships in foraminifera

Zeebe

Biȷma

Hönisch

et al. 2008

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This paper mainly reviews our recent work on the biology and geochemistry of foraminifera with respect to their use as palaeoceanographic proxies. Our approach to proxy validation and development is described, primarily from a modeler's point of view. The approach is based on complementary steps in understanding the inorganic chemistry, inorganic isotope fractionation, and biological controls that determine palaeo-tracer signals in organisms used in climate reconstructions. Integration of laboratory experiments, field and culture studies, theoretical considerations and numerical modelling holds the key to the method's success. We describe effects of life-processes in foraminifera on stable carbon, oxygen, and boron isotopes as well as Mg incorporation into foraminiferal calcite shells. Stable boron isotopes will be used to illustrate our approach. We show that a mechanism-based understanding is often required before primary climate signals can be extracted from the geologic record because the signals can be heavily overprinted by secondary, non-climate related phenomena. Moreover, for some of the proxies, fundamental knowledge on the thermodynamic, inorganic basis is still lacking. One example is stable boron isotopes, a palaeo-pH proxy, for which the boron isotope fractionation between the dissolved boron compounds in seawater was not precisely known until recently. Attempts to overcome such hurdles are described and implications of our work for palaeoceanographic reconstructions are discussed.

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Oxygen isotope exchange between carbonic acid, bicarbonate, carbonate, and water: A re-examination of the data of McCrea (1950) and an expression for the overall partitioning of oxygen isotopes between the carbonate species and water

Cited by 105 publications

References 11 publications

A study of oxygen isotopic fractionation during bio-induced calcite precipitation in eutrophic Baldeggersee, Switzerland

A study of oxygen isotopic fractionation during bio-induced calcite precipitation in eutrophic Baldeggersee, Switzerland

Stable isotopes in deep-sea corals and a new mechanism for “vital effects”

Vital effects and beyond: a modelling perspective on developing palaeoceanographical proxy relationships in foraminifera

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