Stable isotope ecology of land snails from a high-latitude site near Fairbanks, interior Alaska, USA

Land snails have been investigated isotopically in tropical islands and mid-latitude continental settings, while high-latitude locales, where snails grow only during the summer, have been overlooked. This study presents the first isotopic baseline of live snails from Fairbanks, Alaska (64°51′N), a proxy calibration necessary prior to paleoenvironmental inferences using fossils. δ13C values of the shell (− 10.4 ± 0.4‰) and the body (− 25.5 ± 1.0‰) indicate that snails consumed fresh and decayed C3-plants and fungi. A flux-balance mixing model suggests that specimens differed in metabolic rates, which may complicate paleovegetation inferences. Shell δ18O values (− 10.8 ± 0.4‰) were ~ 4‰ higher than local summer rain δ18O. If calcification occurred during summer, a flux-balance mixing model suggests that snails grew at temperatures of ~ 13°C, rainwater δ18O values of ~− 15‰ and relative humidity of ~ 93%. Results from Fairbanks were compared to shells from San Salvador (Bahamas), at 24°51′N. Average (annual) δ18O values of shells and rainwater samples from The Bahamas were both ~ 10‰ 18O-enriched with respect to seasonal (summer) Alaskan samples. At a coarse latitudinal scale, shell δ18O values overwhelmingly record the signature of the rainfall during snail active periods. While tropical snails record annual average environmental information, high-latitude specimens only trace summer season climatic data.