Iron cycling in the environment: new insights from the micro to the macro-scale

环境中的铁循环：从微观到宏观的新见解

• 批准号: RGPIN-2016-05025
• 负责人: Fortin, Danielle
• 金额: $ 2.4万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751207
• 关键词: Iron; cycling; environment; new; insights

Understanding the iron cycle in the environment is of prime importance because iron oxides are highly efficient at sorbing soluble contaminants, such as toxic metals. At first glance, iron cycling appears rather straight forward, i.e., microbial and/or chemical oxidation of ferrous iron and subsequent precipitation of iron oxides and abiotic and/or biotic reduction of ferric iron oxides and subsequent reductive dissolution of the oxides. Recent studies have however shown that the iron cycle is far more complex than we thought and that iron behavior in the environment is closely linked to the presence of other solutes, such as arsenic, aluminum, nitrogen, silicon, sulfur, phosphate, etc. The present proposal therefore aims at investigating iron cycling in natural and synthetic biogenic iron oxides (BIOS) in the presence of several solutes known to affect iron transformation and/or stability. The 3 objectives of this proposal are 1) How do chemical changes affect natural BIOS mineralogy and microbial diversity?, 2) Which chemical factors control the reduction of BIOS? and 3) Does organic matter stabilize BIOS and prevent mineralogical transformation over time? Natural BIOS will be collected from several freshwater sites near Ottawa (pristine and metal contaminated), whereas artificial BIOS will be synthesized in the laboratory. The overarching goal is to bring the “environment”, i.e., BIOS, to the laboratory and modify it by changing a wide range of physico-chemical parameters (i.e., pH, redox, etc.) in order to tease apart the role of other solutes (Al, As, N, S, Si, etc.) in iron cycling at the micro scale using in situ sensors and bulk analyses. The redox stability of BIOS will also be determined using environmentally relevant conditions. In order to elucidate the intricate relationship between iron and other solutes, synthetic BIOS will also be synthesized and used in well controlled systems submitted to the same manipulations as natural BIOS in order to isolate specific chemical and microbial transformations. The various systems will be analyzed for aqueous (using an in situ micro-profiler and micro-electrodes) and solid phase geochemistry, along with microbial activity and diversity. This research project will train several HQPs (7 B.Sc., 2 M.Sc. and 3 Ph.D.) who will be exposed to state-of-the-art techniques in the field of geochemistry and geomicrobiology and gain valuable skills to enter the work force. Results from this proposal will enable us to better predict the fate of toxic metals in the environment where redox and chemical fluctuations occur due to seasonal changes.

了解环境中的铁循环是最重要的，因为铁氧化物在吸收有毒金属等可溶性污染物方面非常有效。乍一看，铁的循环似乎相当简单，即亚铁的微生物和/或化学氧化，随后铁氧化物的沉淀，铁氧化物的非生物和/或生物还原，以及随后氧化物的还原溶解。然而，最近的研究表明，铁的循环比我们想象的要复杂得多，环境中铁的行为与其他溶质的存在密切相关，如砷、铝、氮、硅、硫、磷等。因此，本提案旨在研究在几种已知影响铁转化和/或稳定性的溶质存在的情况下，天然和合成生物氧化铁(BIOS)中的铁循环。这项建议的三个目标是：1)化学变化如何影响自然的基本输入输出系统矿物学和微生物多样性？2)哪些化学因素控制基本输入输出系统的减少？3)随着时间的推移，有机物是否稳定了基本输入输出系统，防止了矿物学的转变？天然的基本输入输出系统将从渥太华附近的几个淡水区收集(原始的和受金属污染的)，而人工基本输入输出系统将在实验室合成。首要目标是将“环境”，即基本输入输出系统，带到实验室，并通过改变广泛的物理化学参数(即，pH、氧化还原等)来对其进行修改。为了区分其他溶质(Al、As、N、S、Si等)的作用。利用现场传感器和块体分析，在微观尺度上研究铁的循环。还将使用与环境相关的条件来确定基本输入输出系统的氧化还原稳定性。为了阐明铁和其他溶质之间的复杂关系，合成的BIOS也将被合成并用于受控良好的系统中，这些系统提交了与天然BIOS相同的操作，以分离特定的化学和微生物转化。将分析各种系统的水相(使用原位显微剖面仪和微电极)和固相地球化学性质，以及微生物的活性和多样性。本研究项目将培训几个HQP(7个学士学位，2个硕士学位)。博士学位3人)世卫组织将接触到地球化学和地球微生物学领域的最先进技术，并获得进入劳动力大军的宝贵技能。这项提议的结果将使我们能够更好地预测由于季节性变化而发生氧化还原和化学波动的环境中有毒金属的命运。