Oxygen isotope systematics of biologically mediated reactions of phosphate: I. Microbial degradation of organophosphorus compounds

Oxygen isotopes of East Asian dinosaurs reveal exceptionally cold Early Cretaceous climates

“…Secondary precipitation of apatite and isotopic exchange during microbially mediated reactions may alter the primary isotopic signal (10,11). However, apatite crystals that make up tooth enamel are large and densely packed, and in the absence of high temperature conditions which Kolodny and others argue that they enable microbial mediated reactions to reset the bone phosphate oxygen isotopic signal, isotopic exchange might not affect the oxygen isotope composition of phosphates even at geological time scales (12,13).…”

Oxygen and strontium isotopes as provenance indicators of fish at archaeological sites: the case study of Sagalassos, SW Turkey

“…Otherwise, the solubility of apatite is so low that O-exchange between phosphate oxygen and water under abiotic conditions has little effect on the d 18 O p value of phosphates even at geological time scales (Blake et al, 1997;Lécuyer et al, 1999;Zazzo et al, 2004a,b). Given the low solubility and porosity of enamel apatite, d 18 O p values can be considered as pristine in the vast majority of fossil settings.…”

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“…We calculated the expected temperature for each station if equilibrium had been reached. δ 18 O p to approach the theoretical equilibrium value because a higher phosphorus demand would stimulate enzyme-mediated reactions to cleave phosphate from organic molecules, which is the primary exchange mechanism for δ 18 O p at these temperatures (Blake et al 1997 increased toward the theoretical equilibrium value as mentioned above). The observed trend in the San Francisco Bay is potentially a mixing between isotopically distinct sources of phosphate.…”

“…Oxygen isotopic analysis of phosphatic mineral samples (apatite) and of dissolved phosphate in water samples has long been realized as an important tool for paleoclimate reconstruction (Longinelli and Nuti 1973;Lécuyer et al 1993;Filippelli and Delaney 1994;Follmi 1995), ecology (Blake et al 1997;Blake et al 1998), and biogeochemical cycling research (Longinelli and Nuti 1968; Longinelli et al 1976;Paytan et al 2002). These analyses however have not been widely applied to dissolved inorganic phosphate (DIP) because traditional phosphate preparation techniques using BiPO 4 fluorination for isotope analyses require large samples, are labor intensive, time consuming, and involve handling dangerous substances such as BrF 5 (Tudge 1960; Longinelli 1966; Longinelli et al 1976;Kolodny et al 1983;Vennemann et al 2002).…”

“…However, most of the P found in nature is strongly bound to oxygen, which has three stable isotopes; hence, phosphate can be analyzed for δ 18 O. Because the P-O bond in phosphate is resistant to inorganic hydrolysis and does not exchange oxygen with water without biological mediation (Longinelli et al 1976;Blake 1997;Blake et al 1997), systematic isotopic variability of the oxygen isotopic composition of phosphate may provide information about temperature and the δ 18 O of water, and can potentially determine P sources and the extent of P cycling in the ocean.…”