Oxygen and carbon isotopic composition of modern terrestrial gastropod shells from Lipari Island, Aeolian Archipelago (Sicily).

Oxygen (delta Os-18) and stable carbon (delta Os-13) isotopic compositions of modern terrestrial gastropod shells from Lipari Island, in the Aeolian Archipelago (Sicily), have been analysed and compared with local meteoric water delta O-18 (delta(18)Op) and vegetation delta C-13 (delta(13)Cv) respectively. Results reveal that the delta Os-18-delta(18)Op relationship over the study area differs from those obtained on continental Europe and Italian shells, implying that even at the scale of the Mediterranean basin different relationships may co-exist. These differences have been interpreted as the increasing influence of Mediterranean vapour water on Tyrrhenian coasts at relatively low altitude (up to similar to 600 m asl), which compensates for the effect of the delta(18)Op, and possibly of temperature, on shell delta O-18. The steady-state flux balance model (FBM), in agreement with previous studies, suggests that snails are active prevalently at night. Shell carbon isotope ratios reflect the delta(18)Cv, as predicted by the metabolic model and represent a valuable tool for identifying C3 plants with very distinct isotopic signatures. (C) 2013 Elsevier B.V. All rights reserved.