Physiological ecology of algal iron acquisition

藻类铁获取的生理生态学

• 批准号: 121751-2006
• 负责人: Weger, Harold
• 金额: $ 1.97万
• 依托单位: University of Regina
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=365095
• 关键词: Physiological; ecology; algal; iron; acquisition

The major objective of this research is to gain a better understanding of the mechanism(s) of iron acquisition by algae, and how the different mechanisms may affect the functioning of aquatic ecosystems (especially freshwater).  The interactions between iron and algae may have implications for regulating the productivity of both freshwater and marine aquatic environments, and also may affect the algal species composition of aquatic systems.       Despite being one of the most abundant elements in the earth's crust, and despite being classified as a "micronutrient" (needed in only small amounts) for plant and algal growth, rather than as a "macronutrient" (for example, nitrogen), iron availability limits productivity of many terrestrial and aquatic ecosystems.  Iron limitation may occur as a result of low amounts of iron in the environment, low biological availability of iron, or a combination of both of these factors.  The "high nutrient low chlorophyll" (HNLC) zones of the oceans are postulated to be limited by the rate of wind-mediated deposition of iron, while some freshwater systems contain iron tightly bound to organic molecules, limiting the biological availability.     Iron limitation in the HNLC zones sets an upper limit on algal (phytoplankton) biomass, and thus sets an upper limit on the rate of photosynthetic carbon dioxide uptake in those regions.  Algal photosynthesis removes carbon dioxide from the atmosphere, an issue that is particularly important in relation to current concerns about global climate change.     The importance of iron regulation of the productivity of freshwater systems has been less investigated than in marine systems, but it is clear that iron binding by dissolved organic matter can reduce biological availability of iron and decrease the rate of algal growth.  Algal photosynthesis represents the largest input of energy into most freshwater systems, thus iron limitation has potentially important regulatory effects on freshwater aquatic ecosystem productivity.     The research will focus on the different mechanisms by which freshwater algal species obtain iron from the environment, and how the biological availability of iron may interact with the various iron acquisition mechanisms to affect the degree of iron uptake and the species responses to different forms of aquatic iron.

本研究的主要目的是更好地了解藻类获取铁的机制，以及不同机制如何影响水生生态系统（尤其是淡水）的功能。铁与藻类之间的相互作用可能对调节淡水和海洋水生环境的生产力具有影响，也可能影响水生系统的藻类组成。 尽管它是地壳中最丰富的元素之一，尽管它被归类为“微量营养素”，（仅需少量）用于植物和藻类生长，而不是作为“常量营养素”（例如氮），铁的有效性限制了许多陆地和水生生态系统的生产力。铁限制可能是由于环境中铁含量低，海洋的“高营养低叶绿素”（HNLC）区被假定受到风介导的铁沉积速率的限制，而一些淡水系统含有与有机分子紧密结合的铁，限制了生物可用性。 HNLC区的铁限制设定了藻类（浮游植物）生物量的上限，从而设定了这些地区光合作用二氧化碳吸收率的上限。藻类光合作用从大气中去除二氧化碳，这是一个特别重要的问题。与当前对全球气候变化的担忧有关。 与海洋系统相比，铁调节淡水系统生产力的重要性研究较少，但很明显，溶解有机物对铁的结合会降低铁的生物有效性并降低藻类生长速率。藻类光合作用是大多数淡水系统的最大能量输入，因此，铁限制对淡水水生生态系统生产力具有潜在的重要调节作用。 该研究将侧重于淡水藻类物种从环境中获得铁的不同机制，以及铁的生物有效性如何与各种铁获取机制相互作用，以影响铁的吸收程度和物种对不同形式的水生铁的反应。