Investigating interspecies correction factors and extending the applicability of benthic foraminiferal oxygen isotopes studies

底栖有孔虫壳的氧同位素组成是解释全球冰量变化和过去海洋水团温度和盐度变化的基本示踪剂之一。尽管它作为一个古海洋学代理几十年来，仍然有相当大的争论底栖有孔虫氧同位素的温度依赖性和共存物种之间的偏移的恒定性。该项目的主要目标是：（1）评价通常出现在中层至深层水团的10个底栖有孔虫的种间氧同位素偏移，（2）检验pH值/碳酸根离子浓度对底栖有孔虫试验的同位素组成有重大影响的假设;（3）提供种间氧同位素校准的限制，以扩大适用性的复合底栖记录在全新世至新近纪时期。我们的核心顶部校准将针对热带印度洋-太平洋地区，迄今为止，该地区的调查很少，并提供了使用一致方法测试碳酸盐离子对广泛的底层水和孔隙水浓度影响的机会。我们将对比这些记录与新的校准数据从东北大西洋边缘，其特征是良好的通风底层水体和孔隙沃茨与碳酸盐离子浓度降低。最后，我们将把我们的研究结果与其他海洋环境的已发表数据相结合，以进一步探索物种间氧同位素偏移的区域变化范围。

The oxygen isotopic composition of benthic foraminiferal shells is one of the fundamental tracers to decipher global variations in ice volume and past changes in the temperature and salinity of oceanic water masses. Despite its use as a paleoceanographic proxy for several decades, there is still considerable debate concerning the temperature dependence of benthic foraminiferal oxygen isotopes and the constancy of offsets between coexisting species. The main objectives of this project are: (1) to evaluate interspecies oxygen isotopic offsets in ten benthic foraminifers that commonly occur in intermediate- to deep-water masses, (2) to test the hypothesis of a significant influence of pH/carbonate ion concentration on the isotopic composition of infaunal foraminiferal tests and (3) to provide constraints for interspecific oxygen isotope calibrations in order to extend the applicability of composite benthic records over the Holocene to Neogene periods. Our core top calibrations will target the tropical Indo-Pacific region, which has so far been sparsely investigated and offers the opportunity to test carbonate ion effects over a wide range of bottom and pore water concentrations, using a consistent methodology. We will contrast these records with new calibration data from the eastern North Atlantic Margin, characterized by well-ventilated bottom water masses and pore waters with reduced carbonate ion concentrations. Finally, we will integrate our findings with published data from other oceanic settings to further explore the range of regional variability in interspecies oxygen isotopic offsets.