Microfluorination for Oxygen isotopes in Biogenic Silica (MOBiS)

生物二氧化硅中氧同位素的微氟化 (MOBiS)

• 批准号: NE/X005747/1
• 负责人: Melanie Leng
• 金额: $ 48.61万
• 依托单位: British Geological Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX005747%2F1
• 关键词: Microfluorination; Oxygen; isotopes; Biogenic; Silica

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.

人类引起的气候变化改变了世界各地的自然环境和人类系统，其广泛和日益严重的影响超出了自然气候的变异性。为了更好地了解环境变化的驱动因素及其对生态系统和地球过程的影响(例如水和碳的移动和储存)，我们可以使用自然档案(例如海洋和湖泊沉积物记录)，其中包含与过去气候变化有关的特定元素(同位素)的化学变化。过去自然环境对气候变化的反应可以提供至关重要的信息，以调查在不同的全球变暖情景下，未来同样的环境可能会如何变化。例如，研究极地地区的冰盖融化对加速全球海平面上升做出了重大贡献。研究极地冰川融化对过去地质时期气候变化的反应，包括在气候比现在更温暖的时期，提供了至关重要的信息，以确定冰川融化的主要控制因素，并确定未来发生应对全球变暖事件的可能性。关于过去环境变化的信息也可以用来评估重大人类影响之前的生态系统状况和过去数千年发生的自然变化水平，环境因人类活动而发生的变化，我们如何监测和恢复今天的生态系统，并防止未来人类活动的影响。构成天然材料的特定化学元素(同位素)的特定量由当时的环境条件决定，随着它们的生长，这些信息被锁定在它们的结构中。例如，生活在海洋中的微生物的贝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(数亿到数百万年)，气候的变化导致海水中氧同位素组成的变化，这些氧同位素组成反过来被保存在沉没并在海底沉积物中堆积的生物的遗骸中。这些遗骸一层接一层地积累，按时间顺序保存着水化学的特征变化；海底越深，沉积物越老。我们可以按顺序恢复这些沉积物，并通过记录来研究骨骼遗骸中的同位素是如何变化的，这使得我们能够重建过去的气候变化。可以从沉积物序列分析的层数越多，我们就可以获得关于过去气候变化的更多细节。在任何水体中生长并建造由玻璃(生物硅)制成的骨骼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，但需要大量样品和危险化学品，而且时间和能源效率都很低。泥沙档案收集费用高、难度大，样品材料有限。与现有的提取方法相结合，这限制了生物硅中氧同位素的信息量，以回答有关过去气候变化的重要问题。为了解决这个问题，我们将购买一种新的系统，该系统结合了自动化的高温样品反应装置和高精度的同位素测量仪器，不需要使用危险化学品，提供更高的样品吞吐量，并需要显著减少样品大小。新系统将使现有方法发生一步变化，使BGS能够处理来自每个沉积物序列的更多样本，并扩大可以分析的环境样本的范围，例如来自海洋、陆地和湖泊环境的样本，这些环境样本不含高浓度的生物硅。