The importance of iron redox reactions and mineral transformations for the fate of phosphorus in the environment

铁氧化还原反应和矿物转化对于环境中磷的归宿的重要性

• 批准号: 454914587
• 负责人: Professor Dr. Andreas Kappler
• 金额: --
• 依托单位: Arbeitsgruppe Geomikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2021
• 资助国家: 德国
• 起止时间: 2020-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/454914587?language=en
• 关键词: importance; iron; redox; reactions; mineral

Phosphorus (P) is an essential but limiting micronutrient for all living organisms and can significantly affect global biogeochemical cycles, ultimately regulating global primary productivity. Environmental P cycle is known to strongly couple with Fe redox cycling, since Fe minerals are abundant in nature, have high surface areas, and have strong P adsorption capacity. Fe(III) oxide-bound P is reported to account for about 9% of P sequestration from water columns of lakes and up to 70.4% in lake sediments and soils. Fe(III) oxides are readily subject to microbial or abiotical reductive dissolution under anoxic conditions, leading to P mobilization or the formation of the Fe(II)-phosphate mineral vivianite. Aqueous and solid Fe(II) species can undergo microbial and abiotic oxidation under both oxic and anoxic conditions in natural environments, resulting in P retention by newly formed Fe(III) oxide minerals. However, an in-depth understanding of how Fe redox cycling affects the transformation of Fe phases and the subsequent fate (mobilization vs retention) of phosphorous is still lacking. The key aim of this proposal is to understand the critical roles of Fe redox reactions and mineral (trans)formations for P cycling in complex environmental settings. Specifically, we will (1) follow the (trans)formation of abiogenic and biogenic Fe(III) oxide minerals during microbial reduction in the presence of P and determine its effect on the fate of P; (2) determine the (trans)formation of vivianite during microbial vs abiotic oxidation and its effect on the fate of P; (3) determine the (trans)formation of Fe(III) phosphate minerals in the co-presence of Fe(III)- and sulphate-reducing bacteria and its effect on the fate of P; (4) determine the (trans)formation of Fe minerals under cyclic redox conditions and its effect on the speciation and fate of P in redox transitions of natural environments. The expected results will deepen our current knowledge on the coupled Fe and P cycles in natural environments and will help to comprehensively understand global P cycling on Earth.

磷(P)是所有生物必需但限制性的微量营养素，可以显著影响全球生物地球化学循环，最终调节全球初级生产力。众所周知，环境磷循环与铁氧化还原循环是强耦合的，因为自然界中铁矿物丰富，比表面积大，对磷具有很强的吸附能力。据报道，铁（III）氧化物结合的磷约占湖泊水柱中磷的9%，在湖泊沉积物和土壤中高达70.4%。铁（III）氧化物在缺氧条件下容易受到微生物或非生物还原性溶解，导致P的动员或铁(II)-磷酸盐矿物钒铁矿的形成。在自然环境中，水中和固体铁（II）可以在有氧和无氧条件下进行微生物和非生物氧化，导致新形成的铁（III）氧化矿物保留P。然而，对铁氧化还原循环如何影响铁相的转变以及随后的磷的命运（动员与保留）的深入了解仍然缺乏。本提案的主要目的是了解在复杂环境下铁氧化还原反应和矿物（转化）形成对磷循环的关键作用。具体来说，我们将(1)在P存在的情况下，跟踪微生物还原过程中非生物源和生物源Fe（III）氧化物矿物的（转化）形成，并确定其对P命运的影响；(2)确定微生物氧化与非生物氧化过程中橄榄石的（转化）形成及其对磷命运的影响；(3)确定铁（III）和硫酸盐还原菌共同存在时铁（III）磷酸盐矿物的（反式）形成及其对磷的命运的影响；(4)确定循环氧化还原条件下Fe矿物的（转化）形成及其对自然环境氧化还原转变中P的形态和命运的影响。预期的结果将加深我们目前对自然环境中铁和磷耦合循环的认识，并有助于全面了解地球上的全球磷循环。