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Stable Carbon and Oxygen Isotopes in Shell Carbonates of modern Land Snails in China and Their Relation to Environment Variables
Author(s) -
Wang Xu,
Zhai Jixuan,
Cui Linlin,
Zhang Shuhua,
Ding Zhongli
Publication year - 2019
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005255
Subject(s) - land snail , shell (structure) , monsoon , isotopes of oxygen , δ13c , precipitation , altitude (triangle) , isotopes of carbon , gastropoda , ecology , snail , east asian monsoon , stable isotope ratio , geology , environmental science , physical geography , climatology , geography , paleontology , geochemistry , biology , total organic carbon , physics , materials science , geometry , mathematics , quantum mechanics , meteorology , composite material
Stable isotopes of land snail fossil shell carbonates (δ 13 C shell and δ 18 O shell ) provide the opportunity to decipher paleodietary and paleoenvironmental changes. However, the environmental meanings of δ 13 C shell and δ 18 O shell remain elusive especially in the monsoonal climate region. To elucidate this, δ 13 C shell and δ 18 O shell of the two most common land snails in China, Cathaica and Bradybaena , were analyzed in this study. Results show that Bradybaena has a wider distribution than Cathaica and provides considerable potential for use in paleoenvironmental reconstruction. In addition, δ 13 C shell of Bradybaena increases with altitude and temperature, decreases with mean annual precipitation, and reflects the isotopic signal of C 3 plants. In contrast, Cathaica δ 13 C shell documents a C 3 /C 4 mixing signal and exhibits only a strong altitude effect. δ 18 O shell of Bradybaena decreases with mean annual precipitation in the Indian monsoon and westerlies regions but increases with mean annual temperature in the East Asian monsoon region; as a strong correlation exists between the two variables, they could thus potentially be used to reconstruct paleotemperatures. However, uncertainties should be recognized due to the complexity of the land‐snails' ecophysiological responses to environmental changes. Cathaica has slightly lower δ 18 O shell than Bradybaena , which suggests that the two land snails have different ecophysiological traits, and the δ 18 O shell of Cathaica follows mean annual temperature in northeast China. This study lays a ground for explaining land snail stable isotopes in paleorecord in China and reasserts the importance of different ecophysiological traits of land snails in paleoclimatic research.