Quantifying phytoplankton evolution through Cretaceous Oceanic Anoxic Event 2

通过白垩纪海洋缺氧事件 2 量化浮游植物的进化

• 批准号: NE/G004986/1
• 负责人: Paul Bown
• 金额: $ 33.25万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FG004986%2F1
• 关键词: Quantifying; phytoplankton; evolution; through; Cretaceous

The geological record contains fossil shells and shell chemistry that allow us to reconstruct ancient Earth environments. This shows us that Earth has seen a wide range of different climates, including times when it was much colder or warmer than it is now. This research project aims to better understand how life responds to these changing climates by using the geological record of a specific warming event. We are especially interested in finding out what drives biological evolution and how much of a part climate plays in this. It is important to understand how life responds to changing environments, because our modern climate is warming rapidly and we need to find out what the impact of these changes will be. Will we see more extinction? Will life in the oceans become less abundant and so provide less food and absorb less carbon dioxide (which would make climate become warmer even faster)? To answer these questions, we will study a climate-warming event that occurred 93 million years ago, in the Cretaceous, when dinosaurs dominated on land. This greenhouse climate interval saw subtropical forests on Antarctica, crocodile-like animals in the Arctic, no ice-caps and sea-levels that were 70m higher than today. This event is known as Oceanic Anoxic Event 2 (OAE2) because it was first recognised by abundant black shale sediments that indicate that the ocean floors had little or no oxygen, allowing the accumulation of large amounts of carbon from plants and animals. As well as all that carbon burial, this event also saw rapid and extreme climate warming with increases of 6-9C within a few tens of thousands of years. Peak temperatures were at least 36C, compared with modern annual mean temperatures that rarely exceed 30C. So this looks like an ideal event for studying the response of life to warming, but there are some problems. The black shales that occurred during this event do not preserve the fossils that we use to measure evolution. The best fossils for this purpose are the shells of microscopic, single-celled plankton, which are produced in their billions and which are normally preserved in sea-floor sediments, worldwide. However, these shells are made from calcium carbonate and in black shales the shells are usually dissolved away because of acidic fluids in the sediment. To overcome this problem, we have searched the world to find rocks in which the fossils are preserved perfectly. We have found two such places where unusual conditions have preserved plankton fossils of the correct age very well, one in Tanzania (eastern Africa) and one in Morocco (NW Africa). Because these rocks are rich in clay and have never been buried deep in the Earth, the fossils have been protected from damage, and though they are over 90 million years old, they look like modern examples. We will use these fossils to collect information that will tell us how the plankton responded through the OAE2 climate warming. We particularly want to find out whether the rate of evolutionary change increased as the environment changed, and whether more species evolved or became extinct. We will also use these fossils to investigate whether certain types of species were more affected than others. For example, were warm-water-loving species more affected than cool-water types, or were species that produced heavier, thicker shells more affected than types that formed small, delicate shells? By looking at these details of evolution, we can find out which kinds of environmental change were most influential, for example, was it water temperature, food supply, or ocean chemistry (acidification) changes. More broadly, these records of plankton evolution will help us understand how these warm climate events operated and how Earth returned to more normal conditions. With a better understanding of how life responded to these past climate events, we will be better able to make predictions of how Earth's biosphere will respond through the coming decades.

地质记录包含贝壳化石和贝壳化学物质，使我们能够重建古代地球环境。这向我们表明，地球经历了多种不同的气候，包括比现在更冷或更温暖的时期。该研究项目旨在通过利用特定变暖事件的地质记录，更好地了解生命如何应对这些不断变化的气候。我们特别感兴趣的是找出推动生物进化的因素以及气候在其中发挥的作用。了解生命如何应对不断变化的环境非常重要，因为我们的现代气候正在迅速变暖，我们需要找出这些变化的影响。我们会看到更多的灭绝吗？海洋中的生物是否会变得更加丰富，从而提供更少的食物并吸收更少的二氧化碳（这将使气候变得更快）？为了回答这些问题，我们将研究 9300 万年前白垩纪发生的气候变暖事件，当时恐龙在陆地上占主导地位。在这段温室气候期间，南极洲出现了亚热带森林，北极出现了类似鳄鱼的动物，没有冰盖，海平面比今天高了 70m。这一事件被称为海洋缺氧事件 2 (OAE2)，因为它首先是由丰富的黑色页岩沉积物识别出来的，这些沉积物表明海底氧气很少或根本没有，从而导致植物和动物积累了大量的碳。除了所有的碳埋藏之外，这一事件还导致了气候迅速而极端的变暖，在几万年内升高了 6-9 摄氏度。峰值气温至少为 36 摄氏度，而现代年平均气温很少超过 30 摄氏度。因此，这看起来像是研究生命对变暖的反应的理想事件，但存在一些问题。这次事件期间出现的黑色页岩并没有保存我们用来衡量进化的化石。为此目的最好的化石是微观单细胞浮游生物的壳，它们的产量达数十亿，通常保存在世界各地的海底沉积物中。然而，这些贝壳是由碳酸钙制成的，在黑色页岩中，由于沉积物中的酸性液体，贝壳通常会被溶解掉。为了解决这个问题，我们在世界各地寻找保存完好的化石的岩石。我们发现了两个这样的地方，在不寻常的条件下很好地保存了正确年龄的浮游生物化石，一个在坦桑尼亚（非洲东部），一个在摩洛哥（非洲西北部）。由于这些岩石富含粘土，而且从未被深埋在地球深处，因此这些化石一直没有受到破坏，尽管它们已有超过 9000 万年的历史，但它们看起来就像现代的例子。我们将利用这些化石收集信息，告诉我们浮游生物如何应对 OAE2 气候变暖。我们特别想知道进化变化的速度是否随着环境的变化而增加，以及是否有更多的物种进化或灭绝。我们还将利用这些化石来调查某些类型的物种是否比其他物种受到的影响更大。例如，喜温水的物种是否比冷水物种更受影响，或者产生更重、更厚壳的物种比形成小而脆弱的壳的物种更受影响？通过观察这些进化细节，我们可以找出哪种环境变化影响最大，例如，水温、食物供应或海洋化学（酸化）变化。更广泛地说，这些浮游生物进化的记录将帮助我们了解这些温暖气候事件如何运作以及地球如何恢复到更正常的状态。通过更好地了解生命如何应对过去的气候事件，我们将能够更好地预测地球生物圈在未来几十年将如何反应。

项目成果

Planktonic foraminiferal and calcareous nannofossil biostratigraphy and magnetostratigraphy of the uppermost Campanian and Maastrichtian at Zumaia, northern Spain

西班牙北部祖马亚坎帕阶和马斯特里赫特阶最上部的浮游有孔虫和钙质超微化石生物地层学和磁性地层学

• DOI: 10.1016/j.cretres.2012.03.011
• 发表时间: 2012-10-01
• 期刊: Cretaceous Research
• 影响因子: 2.1
• 作者: I. Pérez;J. Lees;J. Larrasoaña;J. A. Arz;I. Arenillas
• 通讯作者: I. Arenillas

Lithostratigraphy, biostratigraphy and chemostratigraphy of Upper Cretaceous and Paleogene sediments from southern Tanzania: Tanzania Drilling Project Sites 27-35

坦桑尼亚南部上白垩统和古近纪沉积物的岩石地层学、生物地层学和化学地层学：坦桑尼亚钻探项目站点 27-35

• DOI: http://dx.10.1016/j.jafrearsci.2012.05.006
• 发表时间: 2012
• 期刊: Journal of African Earth Sciences
• 影响因子: 2.3
• 作者: Jimènez Berrocoso À

New and intriguing calcareous nannofossils from the Turonian (Upper Cretaceous) of Tanzania.

来自坦桑尼亚土伦阶（上白垩纪）的新的、有趣的钙质超微化石。

• 发表时间: 2016
• 期刊: Journal of Nannoplankton Research
• 作者: Lees; J.A.
• 通讯作者: J.A.

Exceptionally well-preserved Cretaceous microfossils reveal new biomineralization styles.

保存完好的白垩纪微化石揭示了新的生物矿化方式。

• DOI: http://dx.10.1038/ncomms3052
• 发表时间: 2013
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Wendler JE

Lithostratigraphy, biostratigraphy and chemostratigraphy of Upper Cretaceous sediments from southern Tanzania: Tanzania drilling project sites 21-26

坦桑尼亚南部上白垩统沉积物的岩石地层学、生物地层学和化学地层学：坦桑尼亚钻探项目地点 21-26

• DOI: http://dx.10.1016/j.jafrearsci.2009.07.010
• 发表时间: 2010
• 期刊: Journal of African Earth Sciences
• 影响因子: 2.3
• 作者: Jiménez Berrocoso Á