Mechanistically understanding biomineralisation and ancient ocean chemistry changes to facilitate robust climate model validation

研究地球过去地质时期的暖期和自然高于现代的大气二氧化碳具有重要的社会意义，因为这些信息提供了：i)一种确定我们燃烧化石燃料时气温可能上升多少的方法，ii)一种评估最先进气候模型质量的经验方法。过去的大多数气候信息都来自“替代物”，它将化石物质化学成分的微小变化与其形成环境联系起来，其中有孔虫(单细胞海洋生物)的贝壳可能代表着最广泛使用的档案。不幸的是，没有一个代理系统是完美的，因为它们都对不止一个因素做出反应。例如，基于有孔虫地球化学的古温度计对它们形成的海水的温度和化学都很敏感，后者以一种鲜为人知的方式随着时间的推移而变化。此外，对于有孔虫构建壳的过程中涉及的基本机制也没有达成共识，因此我们不知道代理重建何时可能存在偏见。阿米巴将直接解决这两个问题，方法是对活的有孔虫进行极其新颖的观察，以确定它们是如何形成外壳的，并对海洋过去的化学变化产生必要的记录。这将有助于改变对量化替代数据的解释，改变这种数据集的效用。阿米巴变形虫将把这一知识应用于一项新的新生代数据汇编，从而准确估计关键温室时间段的地球温度。因此，通过促进下一代模型与数据的比较，将首次明确评估最先进的气候模型捕捉温室气候变暖关键特征的能力。

The study of warm intervals in Earth's geologic past with naturally higher-than-modern atmospheric CO2 is of crucial societal importance because this information provides: i) a way of determining how much temperature is likely to rise as we burn fossil fuels, and ii) an empirical means of assessing the quality of state-of-the-art climate models. Most past climate information comes from 'proxies', which relate small changes in the chemical composition of fossil materials to their environment of formation, of which the shells of the foraminifera (unicellular marine organisms) possibly represent the most widely used archive. Unfortunately, no proxy system is perfect, in that they are all responsive to more than one factor. For example, paleothermometers based on the geochemistry of foraminifera are sensitive to both the temperature and chemistry of the seawater they formed in, the latter of which has changed through time in a poorly understood way. In addition, there is no consensus view on even the basic mechanisms involved in the process by which foraminifera build their shell, such that we don't know when proxy reconstructions are likely to be biased. AMOEBA will directly tackle both issues by making extremely novel observations of living foraminifera to determine how they form their shell, and by generating the necessary records of past chemical change in the oceans. This will facilitate a step-change in the interpretationof quantitative proxy data, transforming the utility of such datasets. AMOEBA will apply this knowledge to a new Cenozoic data compilation, producing accurate estimates of Earth's temperature during key greenhouse intervals. Thus, by facilitating the next generation of model-data comparison, the ability of state-of-the-art climate models to capture key features of greenhouse warmth will be unambiguously assessed for the first time.