Stable isotopic analysis of human diet in the Marianas Archipelago, western Pacific.

Proportions of marine vs. terrestrial resources in prehistoric human diets in the southern Mariana Islands (Guam, Rota, Saipan), Micronesia, have been estimated by analysis of stable isotope ratios of carbon and nitrogen in bone collagen and of carbon in apatite. The isotopic composition of marine and terrestrial food resources from the Marianas have also been determined. Experimental evidence shows that collagen carbon isotopes mainly reflect those of dietary protein sources and thus overestimate the contribution of marine animal foods. Marine protein consumption apparently ranges from approximately 20% to approximately 50% on these islands. Experiments also demonstrate the carbon isotope ratio of bone apatite carbonate accurately reflects that of the whole diet. Carbonate carbon isotope data suggest some individuals consumed significant amounts of 13C-enriched (C4) plants or seaweeds. Sugar cane is an indigenous C4 crop and seaweeds are eaten throughout the Pacific, but they have not been considered by archaeologists to have been prehistoric dietary staples. Apatite carbon isotope analysis has apparently identified previously unrecognized prehistoric dietary adaptations in the Mariana Islands, but this must be confirmed by archaeobotanical evidence.

Radiocarbon 14C differentiation of sparkling and carbonated wines.

Specific 14C-activities, percent of modern 14C-activity, and calculated percent of fermentation CO2 are presented for CO2 contained in commercial sparkling wines, labeled as champagne or produced by the bulk (charmat) process. These data are given for the production years 1976-1982. The survey encompassed effervescent wines produced in Spain, Italy, West Germany, California, and New York. Addition of synthetic CO2 to approximately 40 samples represented as sparkling wines was indicated by low 14C-activities of CO2 in these wines. Data for 14C-activity were also presented for the ethanol distilled from sparkling wines for the years 1977-1980. In all cases, the 14C-activity of ethanol was appropriate to the year of vintage.

Isotopic composition of carbon in vinegars.

Measurements of delta 13C and 14C-activity were performed on vinegars from various known sources. Natural vinegar can be distinguished from petrochemical acetic acid by 14C-analysis: Natural vinegar currently gives values of greater than 112% of modern activity; petrochemical acetic acid yields values of 0% of modern activity. Apple cider vinegar can be distinguished from corn-derived vinegar by delta 13C-analysis: Cider vinegar gives delta 13C-values near -26%; corn-derived vinegars yield delta 13C-values near -10%. delta 13C-Analysis also can be applied, with some restrictions, to wine vinegars. These techniques are applied to a series of retail vinegars.