Evolution of Carbon Cycle Dynamics (eCCD)

碳循环动力学的演变 (eCCD)

• 批准号: NE/H022554/1
• 负责人: Heiko Pälike
• 金额: $ 6.51万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH022554%2F1
• 关键词: Evolution; Carbon; Cycle; Dynamics; eCCD

see lead Institution (Bristol): Evolution of Carbon Cycle Dynamics (eCCD) - Summary The global carbon cycle: how much carbon is stored in its interconnected reservoirs (ocean, atmosphere, biosphere, sediments) as well as the fluxes between them, changes with time. For instance, we know from the geological record that the concentration of CO2 in the atmosphere has varied enormously over the last few hundred of millions of years. The chemistry of the oceans also slows varies with time, and the organisms living within the ocean change and evolve. The details of how the carbon cycle 'works', and of particular importance, how well (or not) the concentration of CO2 in the atmosphere (and hence climate) is regulated, thus also changes on geological time-scales. This creates challenges, for instance, in understanding the causes and consequences of past global warming like events and how they can be related to the future. The sediments slowly accumulating in the deep ocean reflect everything that goes on around them and above them, both chemically and biologically. In particularly, the mineral calcium carbonate (CaCO3), which can be found in the form of chalk and limestone rocks today, is a material commonly used in constructing shells and skeletons by marine organisms. Hence, the amount of CaCO3 being buried in sediments tells us something about ancient organisms and ecosystems. In addition, CaCO3 will start dissolving in seawater if the conditions are acidic or the depth (and thus pressure) is very intense, such as at the very bottom of the open ocean. How much of the CaCO3 originally created by organisms that remains and is not dissolved in sediments, thus also tells us something about past ocean chemistry, depth, and when data from many locations is available, ocean circulation. Looking for subtle changes in the composition of ancient mud in hundreds and hundreds of meters of sediment core recovered from the ocean floor by drill ship would be a little like looking for a needle in a haystack. However, nature has been kind us and the transition from white-colored sediments rich in the shells of carbonate marine organisms to clays devoid of carbonate is easy to spot. This point represents a balance between the amount of shells deposited to the sediments and the rate of dissolution. Hence a balance between surface ocean biological processes and deep ocean chemical and circulation processes. In this project by compiling the records from hundreds of different sediment cores recovered in the past decades, we will reconstruct how this balance point has change in depth and time in the different ocean basins. Because sediment records exist as far bask as the Mesozoic and well before the dinosaurs went extinct, we will start there. However, the interpretation of the curve we will produce is not straightforward, because multiple environmental changes can all push and pull this balance point in different directions and with different strengths. We will there fore also configure a computer model representation of the Earth's climate and oceans, its carbon cycle, ocean chemistry, and the composition of sediments in the deep sea for these times in the past. We will use this to explore how the different possible changes in the carbon cycle affect the balance point, and by comparing to our new curve through time, interpret how the carbon cycle has changed over the past 150 million years. This will also allow us to understand how the sensitivity of the carbon cycle and hence climate changes in time to being perturbed, such as by massive greenhouse gas releases. Hence we will not only be able to answer the question: do we live in a particularly 'lucky' or 'unlucky' time in terms of how sensitive our global environment is to the burning of fossil fuels, but we will know why the Earth system responds with a certain degree of sensitivity.

见牵头机构（布里斯托）：碳循环动力学的演变-摘要全球碳循环：有多少碳储存在其相互关联的储存库（海洋、大气、生物圈、沉积物）中，以及它们之间的通量随时间而变化。例如，我们从地质记录中知道，在过去的数亿年里，大气中二氧化碳的浓度变化很大。海洋的化学成分也随着时间的推移而变化，生活在海洋中的生物也在变化和进化。碳循环如何“工作”的细节，特别重要的是，大气中二氧化碳的浓度（以及气候）受到多大程度的调节，因此也会在地质时间尺度上发生变化。例如，这就在理解过去全球变暖等事件的原因和后果以及它们如何与未来联系起来方面带来了挑战。在深海中缓慢积累的沉积物反映了它们周围和上面发生的一切，包括化学和生物学。特别是，矿物碳酸钙（CaCO 3），它可以在白垩和石灰石岩石的形式今天发现，是一种常用的材料，在建造外壳和骨骼的海洋生物。因此，埋藏在沉积物中的CaCO 3的数量告诉我们一些关于古代生物和生态系统的信息。此外，如果条件是酸性的或深度（因此压力）非常强烈，例如在开放海洋的底部，CaCO 3将开始溶解在海水中。有多少最初由生物体产生的CaCO 3保留在沉积物中，而不是溶解在沉积物中，因此也告诉我们一些关于过去海洋化学，深度的信息，以及当来自许多地点的数据可用时，海洋环流。在钻井船从海底采集的数百米的沉积物岩心中寻找古代泥浆成分的细微变化，有点像大海捞针。然而，大自然对我们很仁慈，从富含碳酸盐海洋生物外壳的白色沉积物到不含碳酸盐的粘土的过渡很容易发现。这一点代表了沉积到沉积物中的贝壳数量与溶解速率之间的平衡。因此，表层海洋生物过程与深海化学和环流过程之间保持平衡。在这个项目中，通过汇编过去几十年中回收的数百个不同沉积物岩心的记录，我们将重建这个平衡点在不同海洋盆地中的深度和时间变化。由于沉积物记录存在于中生代，远在恐龙灭绝之前，我们将从那里开始。然而，我们将产生的曲线的解释并不简单，因为多种环境变化都可以在不同的方向和不同的强度上推动和拉动这个平衡点。因此，我们还将配置一个计算机模型，表示地球的气候和海洋，其碳循环，海洋化学，以及过去这些时期深海沉积物的组成。我们将利用这一点来探索碳循环中不同的可能变化如何影响平衡点，并通过与我们新的时间曲线进行比较，解释碳循环在过去1.5亿年中是如何变化的。这也将使我们能够了解碳循环的敏感性，从而了解气候如何随着时间的推移而变化，以受到大规模温室气体排放等干扰。因此，我们不仅能够回答这个问题：我们生活在一个特别“幸运”或“不幸”的时代，就我们的全球环境对化石燃料燃烧的敏感程度而言，而且我们将知道为什么地球系统会以某种程度的敏感性做出反应。

项目成果

A Cenozoic record of the equatorial Pacific carbonate compensation depth

赤道太平洋碳酸盐补偿深度的新生代记录

• DOI: 10.1038/nature11360
• 发表时间: 2012-08-30
• 期刊: NATURE
• 影响因子: 64.8
• 作者: Paelike, Heiko;Lyle, Mitchell W.;Zeebe, Richard E.
• 通讯作者: Zeebe, Richard E.