Microfluorination for Oxygen isotopes in Biogenic Silica (MOBiS)

人为引起的气候变化已经改变了世界各地的自然环境和人类系统，其影响范围广泛且日益严重，超出了自然气候变率的范畴。为了更好地了解驱动环境变化的因素及其对生态系统和地球过程（例如水和碳的运动和储存）的影响，我们可以利用包含与过去气候变化有关的特定元素（同位素）化学变化的自然档案（例如海洋和湖泊沉积物记录）。过去自然环境对气候变化的响应可以为研究在不同全球变暖情景下相同环境在未来如何变化提供重要信息。例如，研究两极地区，那里的冰盖融化对全球海平面上升起到了显著的加速作用。研究过去地质时期（包括气候比现在温暖的时期）的极地冰融化对气候变化的响应，为确定冰融化的主要控制因素和确定未来应对全球变暖事件的可能性提供了关键信息。有关过去环境变化的信息还可用于评估在重大人类影响之前的生态系统状况和过去千年中发生的自然变率水平，环境如何因人类活动而发生变化，我们今天如何监测和恢复生态系统，以及防止未来受到人类活动的影响。构成天然材料的特定化学元素（同位素）的特定数量是由当时的环境条件决定的，这些信息在它们生长的过程中被锁定在它们的结构中。例如，生活在海洋中的微生物的外壳和骨骼记录了它们形成的水中氧同位素的比例。随着时间的推移（数亿年到数百万年），气候的变化导致海水中氧同位素组成的变化，而这些变化又被保存在沉入海底并积聚在海底沉积物中的生物遗骸中。这些残留物一层一层地积累，按时间顺序保存了水化学变化的特征；海底越深，沉积物越古老。我们可以按顺序恢复这些沉积物，并研究骨骼遗骸中的同位素在记录中是如何变化的，这可以重建过去的气候变化。可以从沉积物序列中分析的层数越多，我们就能获得更多关于过去气候变化的细节。在任何水体中生长并形成玻璃骨架（生物硅）的微生物的氧同位素组成受当时的环境条件控制，通常用于重建过去的气候。从这种材料中提取和测量氧同位素是一项高度专业化的技术，但需要大量的样本和危险的化学品，而且时间和能源效率都很低。沉积物档案的收集成本高，难度大，而且样品材料有限。结合现有的提取方法，这限制了从生物成因二氧化硅中的氧同位素中获得的信息量，无法回答有关过去气候变化的重要问题。为了解决这个问题，我们将购买一个新的系统，该系统结合了自动化，高温样品反应装置和高精度同位素测量仪器，不需要使用危险化学品，提供更高的样品吞吐量，并且需要显着减少样品容量。新系统将使现有方法发生阶梯式变化，使BGS能够处理来自每个沉积物序列的更多样品，并扩大可分析的环境样品的范围，例如来自海洋、陆地和湖泊的环境样品，这些环境样品没有高浓度的生物源二氧化硅。

Human-induced climate change has altered natural environments and human systems around the world, with widespread and increasingly severe impacts that are beyond natural climate variability. To develop a greater understanding of what drives environmental change and the influence it will have on ecosystems and Earth-processes (e.g. movement and storage of water and carbon), we can use natural archives (e.g. ocean and lake sediment records) that contain chemical variations of specific elements (isotopes) that relate to past climate change. The response of natural environments to climate change in the past can provide crucial information to investigate how the same environments might change in the future under different scenarios for global warming. For example, examining polar regions where melting ice caps contribute significantly to accelerating global sea level rise. Investigating polar ice melting in response to climate change in the geological past, including in periods that had a warmer climate than today, provides crucial information to identify the main controls on ice melting and determine the likelihood of future events in response to global warming. Information about past environmental change can also be used to assess the condition of an ecosystem before major human impact and the natural levels of variability that have occurred in past millennia, how the environment has changed due to human activity, how we can monitor and restore ecosystems today, and protect against future impacts from human activity.The particular amount of specific chemical elements (isotopes) that natural materials are made of is determined by prevailing environmental conditions and this information is locked in to their structure as they grow. For example, the shells and skeletons of microscopic organisms living in the ocean record the ratio of oxygen isotopes in the water which they formed in. Over time (hundreds to millions of years), changes in climate lead to variations in the oxygen isotope composition of ocean waters and these are in turn preserved in the remains of creatures that have sunk and built up in ocean floor sediments. Layer-by-layer these remains accumulate preserving changes the signature of water chemistry in a time-ordered sequence; the deeper under the ocean floor the older the sediment. We can recover this sediment in sequence and investigate how isotopes in the skeletal remains change through the record, which allows for past changes in climate to be reconstructed. The more layers that can be analysed from a sediment sequence, the more detail we can obtain about past climate change. The oxygen isotope composition of microscopic organisms that grow in any body of water and build skeletons made of glass (biogenic silica) is controlled by prevailing environmental conditions and is routinely used to reconstruct past climate. The extraction and measurement of oxygen isotopes from this material is a highly specialised technique, but requires large samples, dangerous chemicals, and is time and energy inefficient. Sediment archives are collected at great expense and difficultly, and produce limited sample material. Combined with the existing extraction method, this limits the amount of information available from oxygen isotopes in biogenic silica to answer important questions about past climate change.To tackle this issue, we will purchase a new system that combines an automated, high-temperature sample reaction device and high precision isotope measurement instrument that do not require the use of dangerous chemicals, provide substantially higher sample throughput, and require significantly reduced sample sizes. The new system will enable a step-change from the existing method allowing BGS to process many more samples from each sediment sequence and also expand the range of environmental samples that can be analysed, e.g. from ocean, land and lake settings, that do not have high concentrations of biogenic silica.