The biophysical basis of iron-light co-limitation of phytoplankton photosynthesis

铁光共同限制浮游植物光合作用的生物物理基础

• 批准号: NE/C518114/2
• 负责人: Christopher Moore
• 金额: $ 7.96万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FC518114%2F2
• 关键词: biophysical; basis; iron; light; co

Photosynthesis is the conversion of light energy to chemical energy by plants, involving the use of carbon dioxide and the production of oxygen. Globally, photosynthesis is responsible for large transfers of oxygen and carbon between the atmosphere, land and oceans and is an important component of the planet's life support system. In the oceans photosynthesis is carried out by single-celled plants called phytoplankton. These organisms are responsible for half the photosynthesis that occurs on the planet, with the other half being performed by land plants. Phytoplankton are at the bottom of the marine food chain and provide the energy (food) for all the other marine organisms. In common with all plants, phytoplankton need resources to grow, including light, water and nutrients. Water is obviously in plentiful supply in the ocean, however the availability of light and nutrients can limit growth. Such limitation of phytoplankton growth can have important consequences for how the marine ecosystem works and how the biological processes in the ocean affect the removal of carbon dioxide from the atmosphere. One of the nutrients required by phytoplankton is iron. This element, which is very abundant in the crust of our planet, is required in small amounts by all living organisms. However, the amount of iron in the surface of the ocean can be extremely low. Although it has been suspected for some time, it is only within the last 16 years that marine scientists have proved that low iron concentrations limit the growth of phytoplankton in some areas of the oceans. Most of the iron needed by a phytoplankton cell is contained within the structures that plants use to harvest the light energy required for photosynthesis. These structures, called photosystems, convert light energy into electrochemical energy (electrons). Phytoplankton growing in low light environments need a greater number of photosystems in order to harvest enough light. Low light conditions can therefore increase the amount of iron needed by phytoplankton and growth can be limited by both iron and light at the same time. The aim of this project is to increase our understanding of how phytoplankton cope with growing in a low iron environment, frequently under conditions where light may also be low but highly variable. The work will be carried out at the University of Essex in the UK. Phytoplankton will be grown in the laboratory under conditions designed to simulate the ocean. New techniques will be used to measure how the number and activity of photosystems that make up the photosynthetic apparatus adjust to cope with low iron or light conditions. These techniques involve measuring the rate at which light is absorbed by the photosynthetic apparatus and how fast this light energy is passed through the apparatus as electrons. Research will also be performed on ships in the open ocean, working with scientists from Southampton Oceanography Centre. This combination of laboratory and fieldwork is often essential in studies of ocean biology. Work on ships at sea is challenging and the range of measurements made is less than can be achieved on shore. Therefore, information obtained in the laboratory helps us interpret what we observe in the real environment. The answers to questions posed in this project will be important for increasing our understanding of how iron availability effects the growth of phytoplankton, one of the key components of the important ocean ecosystem.

光合作用是植物将光能转化为化学能的过程，涉及二氧化碳的利用和氧气的产生。在全球范围内，光合作用负责在大气、陆地和海洋之间进行大量的氧和碳转移，是地球生命维持系统的重要组成部分。在海洋中，光合作用是由被称为浮游植物的单细胞植物进行的。这些生物负责地球上发生的一半光合作用，另一半由陆地植物完成。浮游植物位于海洋食物链的最底层，为所有其他海洋生物提供能量（食物）。和所有的植物一样，浮游植物的生长也需要资源，包括光、水和营养。海洋中的水显然是充足的，然而光和营养的可用性会限制生长。浮游植物生长的这种限制可能对海洋生态系统如何运作以及海洋中的生物过程如何影响大气中二氧化碳的清除产生重要影响。浮游植物所需的营养物质之一是铁。这种元素在地球的地壳中非常丰富，所有生物都需要少量的这种元素。然而，海洋表面的铁含量可能非常低。尽管人们怀疑这一点已经有一段时间了，但直到最近16年，海洋科学家才证明，低铁浓度限制了海洋某些地区浮游植物的生长。浮游植物细胞所需的大部分铁元素都包含在植物用来收集光合作用所需光能的结构中。这些结构被称为光系统，将光能转化为电化学能（电子）。在弱光环境下生长的浮游植物需要更多的光系统来获取足够的光。因此，弱光条件会增加浮游植物对铁的需求量，而铁和光同时会限制浮游植物的生长。这个项目的目的是增加我们对浮游植物如何在低铁环境中生长的理解，通常在光线也可能很低但变化很大的条件下。这项工作将在英国埃塞克斯大学进行。浮游植物将在实验室中模拟海洋环境的条件下生长。新技术将用于测量组成光合装置的光系统的数量和活性如何调整以应对低铁或光照条件。这些技术包括测量光被光合作用装置吸收的速率，以及光能以电子的形式通过光合作用装置的速度。与南安普顿海洋学中心的科学家合作，研究也将在公海的船上进行。在海洋生物学的研究中，这种实验室和野外工作的结合往往是必不可少的。在海上的船舶上工作是具有挑战性的，测量的范围比在岸上可以实现的要小。因此，在实验室中获得的信息有助于我们解释我们在真实环境中观察到的东西。这个项目提出的问题的答案对于增加我们对铁的可用性如何影响浮游植物生长的理解是重要的，浮游植物是重要的海洋生态系统的关键组成部分之一。

项目成果

Iron limitation of the postbloom phytoplankton communities in the Iceland Basin

• DOI: 10.1029/2008gb003410
• 发表时间: 2009-07-01
• 期刊: GLOBAL BIOGEOCHEMICAL CYCLES
• 影响因子: 5.2
• 作者: Nielsdottir, Maria C.;Moore, Christopher Mark;Achterberg, Eric P.
• 通讯作者: Achterberg, Eric P.

Atmospheric iron inputs and the sub-tropical Atlantic biogeochemical divide

大气铁输入和亚热带大西洋生物地球化学鸿沟

• 作者: Christopher Moore (Author)