Oxygen isotope fractionation between bird bone phosphate and drinking water

Abstract

Oxygen isotope compositions of bone phosphate (δO) were measured in broiler chickens reared in 21 farms worldwide characterized by contrasted latitudes and local climates. These sedentary birds were raised during an approximately 3 to 4-month period, and local precipitation was the ultimate source of their drinking water. This sampling strategy allowed the relationship to be determined between the bone phosphate δO values (from 9.8 to 22.5‰ V-SMOW) and the local rainfall δO values estimated from nearby IAEA/WMO stations (from -16.0 to -1.0‰ V-SMOW). Linear least square fitting of data provided the following isotopic fractionation equation: δO = 1.119 (±0.040) δO - 24.222 (±0.644); R = 0.98. The δO-δO couples of five extant mallard ducks, a common buzzard, a European herring gull, a common ostrich, and a greater rhea fall within the predicted range of the equation, indicating that the relationship established for extant chickens can also be applied to birds of various ecologies and body masses. Applied to published oxygen isotope compositions of Miocene and Pliocene penguins from Peru, this new equation computes estimates of local seawater similar to those previously calculated. Applied to the basal bird Confuciusornis from the Early Cretaceous of Northeastern China, our equation gives a slightly higher δO value compared to the previously estimated one, possibly as a result of lower body temperature. These data indicate that caution should be exercised when the relationship estimated for modern birds is applied to their basal counterparts that likely had a metabolism intermediate between that of their theropod dinosaur ancestors and that of advanced ornithurines.

Stable isotopic characterization of a coastal floodplain forest community: a case study for isotopic reconstruction of Mesozoic vertebrate assemblages

“…The ratio of heavy to light isotope is typically reported as parts per thousand (per mil, ‰) relative to a known standard (denoted using δ , where δ = [[Rsample/Rstandard]−1]) [1,4,8,20,78,79]. Certain stable isotopes, such as carbon (indicated as the ratio 13 C/ 12 C or as δ 13 C, reported hereafter relative to Vienna Pee-Dee Belemnite or VPDB), nitrogen (indicated as the ratio 15 N/ 14 N or as δ 15 N, reported hereafter relative to atmospheric N 2 or AIR) and oxygen (indicated as the ratio 18 O/ 16 O or δ 18 O, reported hereafter relative to Vienna Standard Mean Ocean Water or VSMOW), have been extensively used to study the ecology of a wide variety of taxa [1,3,9,14,15,26,50–54,56,58–60,64–69,73,80–105] from a range of different habitats [1,17,18,49,52,54,57,106–110]. Which isotope is used depends on the study questions, as different isotopic ratios relate to different aspects of the ecology, physiology and environment of an organism [1,3,4,20,78,111].…”

Isotopic systematics point to wild origin of mummified birds in Ancient Egypt

“…Bone oxygen isotope compositions of apatite phosphate range from 20.3‰ to 25.3‰ for ibises, and from 18.7‰ to 24.1‰ for the birds of prey (Table S1 ). Using the Bird phosphate-water fractionation equation 12 , calculated δ 18 O w values of waters ingested by the birds range from − 1.5‰ V-SMOW to + 4.0‰ V-SMOW for ibises, and from − 2.9‰ V-SMOW to + 2.8‰ V-SMOW for the birds of prey (Fig. 2 A).…”

“…2 A). Uncertainties associated with the drinking water estimates equal 0.50 ± 0.03‰ and correspond to the propagation of uncertainty calculated as the quadratic sum of the analytical uncertainties and the mean standard error of the estimate of the bird phosphate-water fractionation equation (σ est = ± 0.45) 12 . Only 3 ibises and 3 birds of prey have drinking water δ 18 O w values that overlap the δ 18 O w range of the Nile estimated from Egyptians δ 18 O p values ( 39 ; Fig.…”

“…Indeed, bird bone apatite phosphate or carbonate has a stable oxygen isotope composition (δ 18 O) reflecting that of its drinking water with a fractionation that depends on species metabolism. By using the fractionation equation established between extant bird phosphate and its drinking water, it is possible to calculate the oxygen isotope composition of local surface waters ingested by birds 12 . In turn, the δ 18 O values of continental surface waters reflect their source (mainly precipitations 13 – 15 ) and history (evaporation, refill 16 , 17 ).…”

Cracking the egg: the use of modern and fossil eggs for ecological, environmental and biological interpretation

“…Because the isotope fractionation between the bone phosphate and egg water is temperature dependent, a time-dependent model can reveal the incubation temperature of the egg. Amiot et al [ 104 ] used the measured isotope values of eggshell and embryo bones of seven different oviraptor specimens to determine the range of incubation temperature was between 35 and 40°C. Both methods, clumped isotope and creating a time-dependent model based on δ 18 O measurements, produce similar estimations for dinosaur body temperature, although the method described in Amiot et al [ 104 ] necessitates the presence of both an embryo and an eggshell from the same individual, which is not commonly discovered.…”