Evolution of Carbon Cycle Dynamics (eCCD)

碳循环动力学的演变 (eCCD)

• 批准号: NE/H023852/1
• 负责人: Andy Ridgwell
• 金额: $ 35.76万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH023852%2F1
• 关键词: Evolution; Carbon; Cycle; Dynamics; eCCD

The global carbon cycle - how much carbon is stored in its interconnected reservoirs (ocean, atmosphere, plants and soils on land, sediments in the deep sea) as well as the fluxes between them, is not set in stone. We know from the geological record that the concentration of CO2 in the atmosphere has varied enormously over the last few hundred million years. The chemistry of the oceans also gradually changes with time and the organisms living within it adjust and evolve. As a result, how the carbon cycle 'works', and particularly, how well (or not) atmospheric CO2 (and hence climate) is regulated in the face of disruption, also changes on geological time-scales. This creates challenges to understanding the causes and consequences of past global warming like events and how such events can be related to potential future changes. Sediments slowly accumulating in the deep ocean reflect what goes on around and above them, both chemically and biologically. Of particular interest to us is the mineral calcium carbonate (CaCO3), which can be found in the form of chalk and limestone rocks today. CaCO3 is used by certain marine organisms for constructing shells and skeletons. Hence, the amount of CaCO3 that in buried in sediments tells us something about ancient organisms and ecosystems. In addition, CaCO3 will start dissolving in seawater if the conditions too are acidic or the depth (and thus pressure) too great. How much CaCO3 originally created by organisms at the surface that escapes dissolution in sediments below to be buried and preserved in the geological record can thus tell us something about the chemistry, depth, and when data from many locations is available, the circulation of the ocean in the past. Looking for subtle changes in the composition of ancient mud in the 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 to us and the transition from white-colored sediments rich in the carbonate shells of dead marine organisms to clays devoid of carbonate is easy to spot. This point represents a fine balance between the amount of shell material being deposited to the sediments and the rate of dissolution of these shells. Hence, this reflects a certain relationship between surface ocean biological processes and deep ocean chemistry and circulation. Any change in these factors will drive sediments rich in CaCO3 or devoid of any trace of carbonate secreting organisms. In this project we will compile the records from many hundreds of different sediment cores that have been recovered since the 1960s. Will identify the 'balance point' in these cores (if one exists) and combine all the confirmation to reconstruct how this balance point has changed in depth and time in the different ocean basins. Because the age of the sediments in some cores extends back to well before the white cliffs of Dover were deposited, we will start our record there. The interpretation of our curve will not be entirely straightforward, because multiple environmental influences all push and pull the balance point in different directions and with different strengths. We will therefore also use 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. We will use this model to explore how the different aspects of the global carbon cycle affect the balance point, and by comparing model predictions to our new curve, interpret how the carbon cycling and the sensitivity of atmospheric pCO2 (and hence climate) to being perturbed by massive greenhouse gas release, has changed over the past 150 million years. 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 burning fossil fuels, but we will know why.

全球碳循环——在相互关联的储存库（海洋、大气、陆地上的植物和土壤、深海沉积物）中储存了多少碳，以及它们之间的通量——并不是一成不变的。我们从地质记录中得知，在过去的几亿年中，大气中二氧化碳的浓度发生了巨大的变化。海洋的化学成分也随着时间的推移而逐渐变化，生活在其中的生物也在进行调整和进化。因此，碳循环如何“运作”，特别是大气中的二氧化碳（以及气候）在面临破坏时如何被调节，也在地质时间尺度上发生了变化。这对理解过去类似全球变暖事件的原因和后果以及这些事件如何与潜在的未来变化联系起来构成了挑战。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化学和生物反应。我们特别感兴趣的是矿物碳酸钙（CaCO3），它可以在今天的白垩和石灰岩中找到。碳酸钙被某些海洋生物用来制造贝壳和骨骼。因此，沉积物中CaCO3的含量告诉我们一些关于古代生物和生态系统的信息。此外，如果环境太酸性或深度（因此压力）太大，CaCO3将开始溶解在海水中。有多少CaCO3最初是由表面的生物产生的，而这些CaCO3没有溶解在下面的沉积物中，被掩埋并保存在地质记录中，因此可以告诉我们一些关于化学、深度的信息，以及当许多地方的数据可用时，过去海洋的循环情况。通过钻探船在海底打捞的数百米长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，从富含死亡海洋生物碳酸盐壳的白色沉积物到缺乏碳酸盐的粘土的转变很容易发现。这一点代表了沉积到沉积物中的贝壳物质的数量和这些贝壳的溶解速度之间的微妙平衡。因此，这反映了表层海洋生物过程与深海化学和环流之间的一定关系。这些因素的任何变化都将导致沉积物富含CaCO3或缺乏任何碳酸盐分泌生物的痕迹。在这个项目中，我们将汇编自20世纪60年代以来已经恢复的数百种不同沉积物岩心的记录。将确定这些岩心中的“平衡点”（如果存在的话），并结合所有确认来重建这个平衡点在不同海洋盆地中的深度和时间变化。因为一些岩心中沉积物的年龄可以追溯到多佛白色悬崖沉积之前，我们将从那里开始记录。我们的曲线的解释并不完全是直截了当的，因为多种环境影响都会以不同的方向和强度推动和拉动平衡点。因此，我们还将使用一个计算机模型来表示地球的气候和海洋、碳循环、海洋化学和深海沉积物的组成。我们将使用这个模型来探索全球碳循环的不同方面如何影响平衡点，并通过将模型预测与我们的新曲线进行比较，解释碳循环和大气二氧化碳分压（以及气候）对大规模温室气体释放的干扰的敏感性在过去1.5亿年里是如何变化的。因此，我们不仅能够回答这个问题：就我们的全球环境对燃烧化石燃料的敏感程度而言，我们生活在一个特别“幸运”或“不幸”的时代，而且我们将知道为什么。

项目成果

Changes in benthic ecosystems and ocean circulation in the Southeast Atlantic across Eocene Thermal Maximum 2 BENTHIC ECOSYSTEM RESPONSE TO ETM2

始新世热最大值 2 东南大西洋底栖生态系统和海洋环流的变化 底栖生态系统对 ETM2 的响应

• DOI: 10.1002/2015pa002821
• 发表时间: 2015
• 期刊: Paleoceanography
• 作者: Jennions S

The role of temperature in the initiation of the end-Triassic mass extinction

温度在三叠纪末大规模灭绝引发中的作用

• DOI: 10.1016/j.earscirev.2020.103266
• 发表时间: 2020
• 期刊: Earth-Science Reviews
• 影响因子: 12.1
• 作者: Petryshyn V

Early Cenozoic Decoupling of Climate and Carbonate Compensation Depth Trends

• DOI: 10.1029/2019pa003601
• 发表时间: 2019-06-01
• 期刊: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
• 影响因子: 3.5
• 作者: Greene, S. E.;Ridgwell, A.;Hoogakker, A. A.
• 通讯作者: Hoogakker, A. A.

Ocean warming, not acidification, controlled coccolithophore response during past greenhouse climate change

• DOI: 10.1130/g37273.1
• 发表时间: 2016-01-01
• 期刊: GEOLOGY
• 影响因子: 5.8
• 作者: Gibbs, Samantha J.;Bown, Paul R.;O'Dea, Sarah A.
• 通讯作者: O'Dea, Sarah A.

Recovering the true size of an Eocene hyperthermal from the marine sedimentary record TRUE SIZE OF EOCENE HYPERTHERMAL

从海洋沉积记录中恢复始新世高温的真实大小 始新世高温的真实大小

• DOI: 10.1002/2013pa002541
• 发表时间: 2013
• 期刊: Paleoceanography
• 作者: Kirtland Turner S