Clumped isotope thermometry applied to bivalve mollusks

高纬度地区双壳类软体动物的壳在季节和年代际尺度上是环境变化的高潜力记录者。然而，在大多数情况下，基于普通氧同位素测定（即贝壳碳酸盐的18o值）的温度估计存在一个缺点，即海水的确切氧同位素组成是未知的。由于碳酸盐与环境水平衡生长，测量到的质量47/44同位素分布与随机分布之间的偏差与环境水的氧同位素组成无关，而完全受温度控制，因此，对酸分解释放的海洋碳酸盐的团块同位素测量已被证明是一种新的强大的古温度计。我们请求资助安装在二氧化碳中测量质量47的团块同位素技术。下一步，我们将研究从方解石和文石软体动物中提取的二氧化碳的温度-(47)关系。最后，将对长寿的A. islandica和快速生长的M. edulis的壳进行（47）和（18O）测量，以重建全新世（Allerød，中世纪气候最佳，小冰期）选定时间间隔内温度和淡水输入的季节性变化。

Shells of bivalve mollusks from higher latitudes are high-potential recorders of environmental variability on seasonal to decadal time-scales. However, temperature estimates based on common oxygen isotope determinations (i.e. (18O-values) of shell carbonate suffer from the weakness that the exact oxygen isotopic composition of the seawater is unknown in most cases. Clumped isotope measurements on CO2 released from marine carbonates by acid digestion have been demonstrated to function as a new powerful paleothermometer, because the deviation between measured and stochastic mass 47/44 isotopologue distributions (as expressed by (47-values) is independent of the oxygen isotopic composition of the ambient water and exclusively controlled by temperature, given that the carbonates grew in equilibrium with the ambient water. We request funding for the installation of the clumped isotope technique for mass 47 measurements in CO2. In a next step, we will study the temperature – (47 relationship for CO2 extracted from calcitic and aragonitic mollusks. Finally, combined (47 and (18O measurements will be performed on shells of the long-lived A. islandica and the fast-growing M. edulis to reconstruct seasonal variations in temperature and freshwater input throughout selected time intervals of the Holocene (Allerød, Medieval Cimate Optimum, Little Ice Age).