NSFGEO-NERC An unexpected requirement for silicon in coccolithophore calcification: ecological and evolutionary implications.

NSFGEO-NERC 颗石藻钙化过程中对硅的意外需求：生态和进化影响。

基本信息

批准号：
NE/N011708/1
负责人：
Glen Wheeler
金额：
$ 51.01万
依托单位：
Marine Biological Association of the United Kingdom
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN011708%2F1
关键词：
NSFGEO NERC unexpected requirement silicon

项目摘要

The oceans cover more than three quarters of the surface of the Earth and tiny algae in our seas are responsible for half of all photosynthesis on our planet. These single celled organisms, known as phytoplankton, form the basis of marine food webs and their activities can have an enormous impact on the geology of our planet. One group of phytoplankton known as the coccolithophores produce a covering of calcium carbonate plates (coccoliths) and can form vast blooms in the oceans. When the coccolithophores die, their coccoliths settle to the ocean floor, leading to the formation of sedimentary rocks, such as chalks and limestones.In many parts of the ocean the low availability of nutrients (such as nitrogen and phosphorus) limits phytoplankton growth. Competition for nutrients plays an important role in determining which phytoplankton species can grow in different environments. One of the most successful phytoplankton groups in modern oceans is the diatoms, which are fast-growing, making it difficult for many other phytoplankton types to compete with them. However, diatoms need lots of dissolved silicon to make their silica cell walls. In some marine environments, the availability of silicon limits the growth of diatoms, allowing other phytoplankton (which do not need silicon) to grow in their place.It is commonly thought that the calcifying coccolithophores have no requirement for silicon. However, we have recently discovered that some important coccolithophore species actually possess silicon transporters that are similar to those used by diatoms. Remarkably, we found that these coccolithophores use silicon to make their calcium carbonate coccoliths. Therefore the processes of silica formation in diatoms and calcite production in coccolithophores, which were previously believed to be distinct processes, show a completely unexpected link. These findings have important implications for the evolution of biomineralisation in phytoplankton and for the competitive interactions between coccolithophores and diatoms.Not all coccolithophores show a requirement for silicon. We found that the species responsible for the massive coccolithophore blooms, Emiliania huxleyi, does not possess silicon transporters and exhibits no need for silicon in the calcification process. The absence of a requirement for silicon may have enabled bloom-forming species to grow better in areas where silicon is low (e.g. after a diatom bloom). There is therefore a clear need to understand the role of silicon in coccolithophore biology.In this proposal we will address this issue using a combination of laboratory experiments and computational modelling approaches. Firstly, we will use molecular genetic and laboratory experiments to determine which of the major coccolithophore species exhibit a requirement for silicon. We will then select species for detailed physiological analysis, to determine how silicon contributes to the formation of coccoliths and how coccolithophores take up silicon from the surrounding seawater. These studies will allow us to examine the evolutionary history of the requirement for silicon and determine when certain lineages appear to have lost this trait. Using parameters on Si uptake and usage derived from our experimental work, we will use computer simulations to model global coccolithophore distributions and identify environments where the requirement for Si appears to be playing an important role in coccolithophore ecology.The research will provide novel insight into physiology, ecology and evolution of coccolithophores, including information on how and why coccoliths are produced, which is currently poorly understood. The research will also inform us on the evolution of coccolith formation, which will be vitally important if we are to understand how coccolithophores have been influenced by past changes in the Earth's climate and how they may respond to changes in the future.

海洋覆盖了地球表面四分之三以上的面积，海洋中的微小藻类负责地球上一半的光合作用。这些单细胞生物被称为浮游植物，构成了海洋食物网的基础，它们的活动可以对我们星球的地质产生巨大影响。一组被称为颗石藻的浮游植物会产生碳酸钙板（颗石藻）覆盖物，并可以在海洋中形成巨大的水华。当颗石藻死亡时，它们的颗石沉降到海底，形成沉积岩，例如白垩和石灰石。在海洋的许多地方，营养物质（例如氮和磷）的低可用性限制了浮游植物的生长。营养物质的竞争在决定哪些浮游植物物种可以在不同环境中生长方面起着重要作用。现代海洋中最成功的浮游植物群之一是硅藻，它们生长迅速，使得许多其他浮游植物类型难以与它们竞争。然而，硅藻需要大量溶解的硅来形成二氧化硅细胞壁。在一些海洋环境中，硅的可用性限制了硅藻的生长，从而允许其他浮游植物（不需要硅）在其位置生长。通常认为钙化球石藻不需要硅。然而，我们最近发现一些重要的颗石藻物种实际上拥有与硅藻相似的硅转运蛋白。值得注意的是，我们发现这些颗石藻使用硅来制造碳酸钙颗石。因此，硅藻中二氧化硅的形成过程和颗石藻中方解石的产生过程，以前被认为是不同的过程，却显示出完全意想不到的联系。这些发现对于浮游植物生物矿化的进化以及颗石藻和硅藻之间的竞争性相互作用具有重要意义。并非所有颗石藻都表现出对硅的需求。我们发现，导致大量颗石藻大量繁殖的物种——Emiliania huxleyi，不具有硅转运蛋白，并且在钙化过程中不需要硅。不需要硅可能使得水华形成物种在硅含量低的地区（例如硅藻水华之后）生长得更好。因此，显然需要了解硅在颗石藻生物学中的作用。在本提案中，我们将结合实验室实验和计算建模方法来解决这个问题。首先，我们将利用分子遗传学和实验室实验来确定哪些主要颗石藻物种表现出对硅的需求。然后，我们将选择物种进行详细的生理分析，以确定硅如何促进颗石藻的形成以及颗石藻如何从周围的海水中吸收硅。这些研究将使我们能够研究对硅的需求的进化历史，并确定某些谱系何时似乎失去了这种特性。利用从我们的实验工作中得出的硅吸收和使用参数，我们将使用计算机模拟来模拟全球颗石藻分布，并确定硅需求似乎在颗石藻生态学中发挥重要作用的环境。该研究将为生理学提供新的见解、球石藻的生态学和进化，包括有关球石藻如何以及为何产生的信息，目前人们对此知之甚少。这项研究还将让我们了解颗石藻形成的演化过程，如果我们要了解颗石藻如何受到过去地球气候变化的影响以及它们如何应对未来的变化，这将是至关重要的。

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）

A critical trade-off between nitrogen quota and growth allows Coccolithus braarudii life cycle phases' to exploit varying environment

氮配额和生长之间的关键权衡使得布氏颗石藻生命周期阶段能够利用不同的环境

DOI：
http://dx.10.5194/egusphere-2023-880
发表时间：
2023
期刊：
影响因子：
0
作者：
De Vries J
通讯作者：
De Vries J

Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and relevance for the environment

三种广泛分布的海洋浮游植物物种的甲烷产生：释放率、前体化合物以及与环境的相关性

DOI：
http://dx.10.5194/bg-2019-245
发表时间：
2019
期刊：
影响因子：
0
作者：
Klintzsch T
通讯作者：
Klintzsch T

Coccospheres confer mechanical protection: New evidence for an old hypothesis.

球球提供机械保护：旧假设的新证据。

DOI：
10.1016/j.actbio.2016.07.036
发表时间：
2016-09-15
期刊：
Acta biomaterialia
影响因子：
9.7
作者：
B. N. Jaya;Ramona Hoffmann;C. Kirchlechner;G. Dehm;Christina Scheu;Gerald Langer
通讯作者：
Gerald Langer

Haplo-diplontic life cycle expands coccolithophore niche

单倍体二倍体生命周期扩大了颗石藻生态位