Icehouse tropical climates and plankton evolution

冰室热带气候和浮游生物进化

基本信息

批准号：
NE/G014817/1
负责人：
Bridget Wade
金额：
$ 70.25万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Fellowship
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%2FG014817%2F1
关键词：
Icehouse tropical climates plankton evolution

项目摘要

The Earth today has major ice caps on Antarctica and Greenland, but this was not always the case. The planned research focuses on climate change during a time period known as the Oligocene (34 to 24 million years ago). This interval of time is of particular interest as it began with a big shift in climate. Before 34 million years ago, the climate was warm - so warm that there was no permanent ice on Antarctica and palm trees stretched as far north as the Arctic Circle. However, this warm period ended abruptly at 34 million years ago when a large ice sheet developed on Antarctica. Once the Antarctic ice cap was established, it waxed and waned many times between periods with relatively little ice and periods with very expansive ice sheets. My previous work has shown that like a flickering switch, the climate was balanced on the cusp between glaciated and greenhouse states, making the Oligocene particularly exciting to research if we want to understand a world somewhat warmer than the modern. However the Oligocene climate remains something of a mystery because, until now, there have been no good records to document climate changes in the tropics. The tropics are vital because it is heat differences between the tropics and poles that ultimately drives the circulation of the atmosphere and oceans. Unfortunately tropical Oligocene sediments are fairly scarce and most previously acquired records are incomplete or do not have sufficiently well-preserved microfossils for the kind of analyses that are required to reveal the climate. Many questions still need to be addressed, such as; What were conditions in the tropics like while the poles were undergoing these dramatic climate swings? Did the climate cool gradually before each phase of ice build up, and warm before the ice caps waned? How did the Earth's biota respond to the big shifts in climate? These questions can be addressed by analysing the geochemical composition of microfossils from marine sediments. I work with tiny microscopic fossils called foraminifera. These are single-celled organisms that commonly build a skeleton made from calcium carbonate. Over time the shells of dead foraminifera accumulate in marine sediments and yield a long and valuable fossil record, which palaeontologists can exploit to gain information on oceans and climate of the past. One of the most marvellous things about these tiny organisms is that the chemistry of their shells reflects the water in which they grew and other features of their environment. Analysis of fossil shells can be employed to reconstruct many aspects of the climate, such as the temperature of the sea surface and global ice volume. In the past few years I have set about to systematically identify and acquire all the best tropical samples that have very abundant and well preserved foraminifera, making them ideal for chemical analyses and to study the oceans of the Oligocene. More collecting is also required, in areas such as Puerto Rico and East Africa. A detailed study of foraminifer chemistry will build an accurate picture of how the Oligocene climate changed and will lead to a greater understanding of climatic events and oceanographic processes. Studying intervals of dramatic climate change, allow a greater understanding of the oceans and climate system. Knowledge of the climate is particularly important to society in light of current increases in atmospheric carbon dioxide which is predicted to cause rapid and profound global warming. Climatic modelling experiments have suggested that the climate shift from a warm to cool Earth during the Oligocene may have been related to a reduction in atmospheric carbon dioxide levels (in a way, the reverse process of what is predicted for the future). These records will provide the data to test and refine climate models and may provide information useful for predicting the future climate response of abrupt warming, from the ice sheets to the tropics.

当今的地球上有主要的冰盖，上面有南极和格陵兰岛，但并非总是如此。计划的研究重点是在渐新世（34至2400万年前）的时期内的气候变化。这个时间间隔尤其引起人们的关注，因为它始于气候的巨大变化。在3400万年前，气候温暖 - 如此温暖，以至于南极和棕榈树上没有永久性的冰，一直延伸到北极圈。但是，这个温暖的时期突然结束，3400万年前，当时大型冰盖在南极洲开发。一旦建立了南极冰盖，它在冰块和时期较少的时期和冰盖非常膨胀的时期之间的蜡和衰减很多次。我以前的工作表明，就像闪烁的开关一样，气候在冰川和温室状态之间的风口峰上平衡，如果我们想了解一个比现代温暖的世界，则渐新世特别令人兴奋。然而，渐新世气候仍然是一个谜，因为到目前为止，还没有有很好的记录来记录热带地区的气候变化。热带地区至关重要，因为它是热带地区和两极之间的热差，最终驱动了大气和海洋的循环。不幸的是，热带渐新世沉积物相当稀缺，大多数先前获得的记录不完整或没有足够保存完好的微化石来揭示气候所需的分析。仍然需要解决许多问题，例如；在杆子经历这些戏剧性的气候波动时，热带地区的条件是什么？在冰的每个阶段堆积之前，气候是否逐渐冷却，在冰盖降低之前温暖？地球的生物群落如何应对气候的重大转变？这些问题可以通过分析来自海洋沉积物的微化石的地球化学组成来解决。我使用称为有孔虫的微小化石。这些是通常建立由碳酸钙制成的骨骼的单细胞生物。随着时间的流逝，死去的有孔虫的壳会积聚在海洋沉积物中，并产生长长而有价值的化石记录，古生物学家可以利用这些记录来获取有关海洋和过去气候的信息。这些微小生物最奇妙的事情之一是，壳的化学反映了它们生长的水和环境的其他特征。化石壳的分析可用于重建气候的许多方面，例如海面温度和全球冰量。在过去的几年中，我开始系统地识别和获取所有具有非常丰富且保存完好的有孔虫的最佳热带样品，使其非常适合化学分析并研究渐新世的海洋。在波多黎各和东非等地区，还需要更多收集。对有孔虫化学的详细研究将为渐新世气候如何变化而准确地描绘出对气候事件和海洋学过程的更多了解。研究急剧变化的间隔，可以更了解海洋和气候系统。鉴于大气二氧化碳的当前增加，对气候的了解对社会尤为重要，这预计会导致快速而深刻的全球变暖。气候建模实验表明，在渐新世期间，从温暖到凉地的气候转移可能与大气二氧化碳水平的降低有关（在某种程度上，预测未来预测的反向过程）。这些记录将提供数据来测试和完善气候模型，并可能提供有关预测突然变暖的未来气候反应的信息，从冰盖到热带。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Paleoenvironmental conditions for the development of calcareous nannofossil acme during the late Miocene in the eastern equatorial Pacific

DOI：
10.1002/2013pa002506
发表时间：
2014-03
期刊：
Paleoceanography
影响因子：
0
作者：
Catherine Beltran;Gabrielle Rousselle;J. Backman;B. Wade;M. Sicre
通讯作者：
Catherine Beltran;Gabrielle Rousselle;J. Backman;B. Wade;M. Sicre

SYSTEMATIC TAXONOMY OF EARLY-MIDDLE MIOCENE PLANKTONIC FORAMINIFERA FROM THE EQUATORIAL PACIFIC OCEAN: INTEGRATED OCEAN DRILLING PROGRAM, SITE U1338

赤道太平洋早中新世浮游有孔虫的系统分类：综合海洋钻探计划，站点 U1338

DOI：
发表时间：
2013
期刊：
JOURNAL OF FORAMINIFERAL RESEARCH
影响因子：
1.1
作者：
Fox Lyndsey R.
通讯作者：
Fox Lyndsey R.

Middle Miocene to Pleistocene Planktonic Foraminiferal Biostratigraphy in the Eastern Equatorial Pacific Ocean

DOI：
10.2517/1342-8144-17.1.91
发表时间：
2013-04
期刊：
影响因子：
0
作者：
H. Hayashi;Kyoko Idemitsu;B. Wade;Yuki Idehara;K. Kimoto;H. Nishi;H. Matsui
通讯作者：
H. Hayashi;Kyoko Idemitsu;B. Wade;Yuki Idehara;K. Kimoto;H. Nishi;H. Matsui

Integrated biomagnetochronology for the Palaeogene of ODP Hole 647A: implications for correlating palaeoceanographic events from high to low latitudes

ODP 647A 孔古近纪的综合生物磁年代学：对从高纬度到低纬度古海洋事件进行关联的意义