Oxygen isotope variations in phosphate of biogenic apatites, IV. Mammal teeth and bones

Groups of rats grown from birth to death in identical conditions, but with different δ¹⁸O of drinking water (δ_w), were studied for variations of δ¹⁸O of their body water (δ_BW) and bone phosphate (δ_p). There is a high linear correlation (r = 0.99) between δ_BW and between δ_p and δ_w. The regression lines have similar slope coefficients (0.53 and 0.49). Values of δ_p of different teeth and bones are the same, within the precision of the method (±0.5‰). The isotopic fractionation coefficient between phosphate and body water is 1.0178 and close to the estimated value of 1.0173 derived from the phosphate paleotemperature equation. Deviations from constant fractionation between bone phosphate and environmental drinking water depend primarily on rates of drinking and metabolism. Environment conditions have relatively little effect on oxygen isotope fractionation between water sources and bone phosphate.