Culture experiments on the environmental controls of trace metal ratios (Mg/Ca, B/Ca, U/Ca) recorded in calcareous tests of bipolar deep-sea benthic foraminifera

极地海洋是我们最重要的气候放大器：首先，极地深水的产生驱动了全球温盐传送带，从而推动了气候。其次，冰川时期的南极深水是最大的海洋大气二氧化碳汇，但有争议的是它仍然是。使用关于物理和地球化学性质变化的有效和可化石的替代物，对于评估冰川-间冰期的变化、两极深水的现代和未来变化至关重要。在这方面，通过分析有孔虫测试中记录的痕量金属(镁/钙、铀/钙、硼/钙)比值来估计钙化温度、碱度、碳酸盐离子饱和度和pH是常用的方法。然而，对于北极和南大洋深海底栖有孔虫，缺乏受岩心-顶部样品或培养实验约束的校准曲线。新开发的高压水族箱最近促进了我们最信任的古深水记录器Fontbotia wuellerstorfi和Uvilerina peregrina的第一次高效培育(产生后代)。在不同的实验装置中，将使用相同的设施在不同温度和不同碳酸盐化学成分的水域中培养这些有孔虫及其相关物种，以建立两个极地海洋的第一个物种特定痕量金属校准曲线。对来自两个大洋的150多个岩心地点进行的岩心顶部分析将验证实验结果。

The Polar Oceans are our most important climate amplifiers: First, the production of polar deep waters drives the Global Thermohaline Conveyer Belt, and thus, climate. Second, the Antarctic deep water during glacial time was, disputably still is, the largest marine sink of atmospheric CO2. Employment of effective and fossilisable proxies on changes in the physical and geochemical properties is essential to assess glacial-interglacial variabilities, modern and future changes in bipolar deep-waters. In this respect, analyses on trace metal (Mg/Ca, U/Ca, B/Ca) ratios recorded in tests of foraminifers to estimate calcification temperatures, alkalinity, carbonate ion saturation, and pH are common methods. However, for the Arctic and Southern Ocean deep-sea benthic foraminifera calibration curves constrained by either core-top samples or culture experiments are lacking. Newly developed high-pressure aquaria have recently facilitated the first efficient cultivation (producing offspring) of our most trusted palaeodeep-water recorders Fontbotia wuellerstorfi and Uvigerina peregrina. In different experimental set-ups the same facilities will be used to cultivate these foraminifera and associated species at different temperatures and in waters with different carbonate chemistries to establish the first species-specific trace metal calibration curves for both Polar Oceans. Core top analyses on more than 150 core sites from both oceans will verify the experimental results.