Controls on iron availability to marine phytoplankton

控制海洋浮游植物的铁利用率

• 批准号: NE/V01451X/2
• 负责人: Fengjie LIU
• 金额: $ 55.04万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FV01451X%2F2
• 关键词: Controls; iron; availability; marine; phytoplankton

Anthropogenic greenhouse gas emissions such as carbon dioxide (CO2) are causing climate change, global warming, and ocean acidification. Microscopic plants called phytoplankton, living in the surface oceans, sequester 50% of global CO2 and supply >50% of new nitrogen used for primary production. Other than light and major nutrients, phytoplankton growth is strongly influenced by availability of the metal iron (Fe), because the metal is essential for photosynthesis and nitrogen fixation, but is very scarce in the open ocean. Iron is so important that seeding the metal into Fe-poor areas has been proposed as a viable method for controlling climate change by enhancing bio-uptake of atmospheric CO2 by phytoplankton. In order to understand how Fe controls atmospheric CO2 levels and oceanic productivity, it is important to first attempt to understand the controls on availability of the metal to marine phytoplankton. The prevailing view is that metal bioavailability depends upon its chemical forms (i.e., metal speciation) in ambient bulk waters; however, data from our recent studies are inconsistent with the long-standing paradigm. In the proposed project, I will challenge this long-standing paradigm by studying the Fe speciation in the phycosphere, a micrometer scale space which directly surrounds a phytoplankton cell, through the use of novel nano-technologies and inter-disciplinary approaches. Phytoplankton directly take up nutrients including Fe from the phycosphere, rather than directly from bulk seawater, however the Fe speciation in this micro-scale space has not previously been studied. The lack of knowledge on phycosphere Fe speciation would potentially result in serious under or overestimation of oceanic Fe availability in current and future oceans, and lead to erroneous prediction of how ocean ecosystem responds to Climate Change. The interdisciplinary project will provide a new view on the fundamental processes in Fe acquisition by phytoplankton, and it will certainly help improve the capability and accuracy of international agencies such as the Intergovernmental Panel on Climate Change to assess the sensitivity of planetary system to Climate Change.

二氧化碳 (CO2) 等人为温室气体排放正在导致气候变化、全球变暖和海洋酸化。生活在海洋表面的浮游植物微型植物吸收了全球 50% 的二氧化碳，并提供了超过 50% 的用于初级生产的新氮。除了光和主要营养物质外，浮游植物的生长还受到金属铁 (Fe) 可用性的强烈影响，因为这种金属对于光合作用和固氮至关重要，但在公海中非常稀缺。铁是如此重要，以至于有人提出将金属播种到缺铁地区，作为通过增强浮游植物对大气二氧化碳的生物吸收来控制气候变化的可行方法。为了了解铁如何控制大气二氧化碳水平和海洋生产力，首先尝试了解海洋浮游植物对金属可用性的控制非常重要。普遍的观点是，金属的生物利用度取决于其在周围散装水域中的化学形态（即金属形态）；然而，我们最近研究的数据与长期存在的范式不一致。在拟议的项目中，我将通过使用新颖的纳米技术和跨学科方法来研究藻圈（直接围绕浮游植物细胞的微米级空间）中的铁形态，从而挑战这一长期存在的范式。浮游植物直接从藻圈中吸收包括铁在内的营养物质，而不是直接从大量海水中吸收，然而，此前尚未研究过这一微尺度空间中的铁形态。缺乏对藻圈铁形态的了解可能会导致当前和未来海洋中铁的可用性严重低估或高估，并导致对海洋生态系统如何应对气候变化的错误预测。该跨学科项目将为浮游植物获取铁的基本过程提供新的视角，也必将有助于提高政府间气候变化专门委员会等国际机构评估行星系统对气候变化敏感性的能力和准确性。