Past aquatic environments in the Levant inferred from stable isotope compositions of carbonate and phosphate in fish teeth

Here we explore the carbon and oxygen isotope compositions of the co-existing carbonate and phosphate fractions of fish tooth enameloid as a tool to reconstruct past aquatic fish environments and harvesting grounds. The enameloid oxygen isotope compositions of the phosphate fraction (delta O-18(PO4)) vary by as much as similar to 4 parts per thousand for migratory marine fish such as gilt-head seabream (Sparus aurata), predominantly reflecting the different saline habitats it occupies during its life cycle. The offset in enameloid Delta O-18(CO3-PO4) values of modern marine Sparidae and freshwater Cyprinidae from the Southeast Mediterranean region vary between 8.1 and 11.0 parts per thousand, similar to values reported for modern sharks. The mean delta C-13 of modern adult S. aurata and Cyprinus carpio teeth of 0.1 +/- 0.4 parts per thousand and -6.1 +/- 0.7 parts per thousand, respectively, mainly reflect the difference in delta C-13 of dissolved inorganic carbon (DIC) of the ambient water and dietary carbon sources. The enameloid Delta O-18(CO3-PO4) and delta C-13 values of ancient S. aurata (Holocene) and fossil Luciobarbus sp. (Cyprinidae; mid Pleistocene) teeth agree well with those of modern specimens, implying little diagenetic alteration of these tooth samples. Paired delta O-18(PO4)-delta C-13 data from ancient S. aurata teeth indicate that hypersaline water bodies formed in the Levant region during the Late Holocene from typical Mediterranean coastal water with high evaporation rates and limited carbon input from terrestrial sources. Sparid tooth stable isotopes further suggest that coastal lagoons in the Eastern Mediterranean had already formed by the Early Holocene and were influenced by terrestrial carbon sources. Overall, combined enameloid oxygen and carbon isotope analysis of fish teeth is a powerful tool to infer the hydrologic evolution of aquatic environments and assess past fishing grounds of human populations in antiquity.