Oxygen isotope ratios in German groundwater

Abstract

The natural variation in the ¹⁸O/¹⁶O ratio in precipitation has a characteristic global pattern^1,2, a continuous decrease from the Equator towards the polar regions, corresponding to the worldwide distribution of the local mean annual temperature. This global pattern is not, however, sensitive enough to predict the local ¹⁸O/¹⁶O ratio in precipitation. A survey of ground-water throughout the FRG was obtained from about 900 samples of the municipal water supply. Using a multicorrelation study we demonstrate here that both distance from the coast and height above sea level determine the local ¹⁸O/¹⁶O ratio, and that this ratio generally decreases from the northern coast towards the southern mountainous region. The geographical variation in the ¹⁸O/¹⁶O ratio may serve as a basis for palaeoclimatological, plant-physiological and food-analytical applications. The practical applications are demonstrated by a study of the ¹⁸O/¹⁶O ratio of water in grapes and commercial wines; such observations may help to trace where a commercial wine originated.