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This paper reports a high-resolution isotopic study of medieval horse mobility, revealing their origins and in-life mobility both regionally and internationally. The animals were found in an unusual horse cemetery site found within the City of Westminster, London, England. Enamel strontium, oxygen, and carbon isotope analysis of 15 individuals provides information about likely place of birth, diet, and mobility during the first approximately 5 years of life. Results show that at least seven horses originated outside of Britain in relatively cold climates, potentially in Scandinavia or the Western Alps. Ancient DNA sexing data indicate no consistent sex-specific mobility patterning, although three of the five females came from exceptionally highly radiogenic regions. Another female with low mobility is suggested to be a sedentary broodmare. Our results provide direct and unprecedented evidence for a variety of horse movement and trading practices in the Middle Ages and highlight the importance of international trade in securing high-quality horses for medieval London elites.

The extent to which both water source and atmospheric humidity affect δ2 H values of terrestrial plant leaf waxes will affect the interpretations of δ2 H variation of leaf waxes as a proxy for hydrological conditions. To elucidate the effects of these parameters, we conducted a long-term experiment in which we grew two tree species, P opulus fremontii and B etula occidentalis, hydroponically under combinations of six isotopically distinct waters and two different atmospheric humidities. We observed that leaf n-alkane δ2 H values of both species were linearly related to source water δ2 H values, but with slope differences associated with differing humidities. When a modified version of the Craig- Gordon model incorporating plant factors was used to predict the δ2 H values of leaf water, all modelled leaf water values fit the same linear relationship with n-alkane δ2 H values. These observations suggested a relatively constant biosynthetic fractionation factor between leaf water and n-alkanes. However, our calculations indicated a small difference in the biosynthetic fractionation factor between the two species, consistent with small differences calculated for species in other studies. At present, it remains unclear if these apparent interspecies differences in biosynthetic fractionation reflect species-specific biochemistry or a common biosynthetic fractionation factor with insufficient model parameterization. [ABSTRACT FROM AUTHOR]

The article discusses a research done during the cruise ARK-XXIII/1 aboard Polarstern in June 2008, as part of the project "Climate control on Holocene variability in Arctic sea-ice and marine carbon export production" or ICECARB. ICECARB aims to determine processes responsible for the variability of changes in the Arctic climate system and their impact on the marine ecosystem. The cruise ARK-XXIII/1 aimed to improve the validation and calibration of the existing classical proxies for environmental conditions. The collected filters from 45 stations will be analyzed in the laboratory of ICTA Barcelona while water samples will be partly analyzed at AWI Bremerhaven. Liquid and gas chromatography and mass spectrometry will be used for biomarker analyses.

The extent to which both water source and atmospheric humidity affect δ(2)H values of terrestrial plant leaf waxes will affect the interpretations of δ(2)H variation of leaf waxes as a proxy for hydrological conditions. To elucidate the effects of these parameters, we conducted a long-term experiment in which we grew two tree species, Populus fremontii and Betula occidentalis, hydroponically under combinations of six isotopically distinct waters and two different atmospheric humidities. We observed that leaf n-alkane δ(2)H values of both species were linearly related to source water δ(2)H values, but with slope differences associated with differing humidities. When a modified version of the Craig-Gordon model incorporating plant factors was used to predict the δ(2)H values of leaf water, all modelled leaf water values fit the same linear relationship with n-alkane δ(2)H values. These observations suggested a relatively constant biosynthetic fractionation factor between leaf water and n-alkanes. However, our calculations indicated a small difference in the biosynthetic fractionation factor between the two species, consistent with small differences calculated for species in other studies. At present, it remains unclear if these apparent interspecies differences in biosynthetic fractionation reflect species-specific biochemistry or a common biosynthetic fractionation factor with insufficient model parameterization., (© 2014 John Wiley & Sons Ltd.)