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)是所有生物体必需但有限的微量营养素，可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。环境磷循环与铁氧化还原循环有很强的耦合关系，因为铁矿物丰富，比表面积大，对磷的吸附能力强。据报道，Fe(III)氧化物结合磷约占湖泊水柱磷固定总量的9%，在湖泊沉积物和土壤中的固定比例高达70.4%。Fe(III)氧化物在缺氧条件下容易发生微生物或非生物还原溶解，导致磷的活化或形成Fe(II)-磷酸盐矿物蓝晶石。在自然环境中，水相和固体相的Fe(II)均可在有氧和缺氧条件下进行微生物和非生物氧化，从而导致新形成的Fe(III)氧化物矿物对P的截留。然而，对于铁的氧化还原循环如何影响铁相的转变以及随后磷的去向(活化与保留)仍然缺乏深入的了解。这一建议的主要目的是了解在复杂的环境环境中，铁氧化还原反应和矿物质(转化)在磷循环中的关键作用。具体地说，我们将(1)跟踪微生物在磷存在下还原过程中非生物和生物来源的Fe(III)氧化物矿物的(反式)形成，并确定其对P的去向的影响；(2)确定在微生物与非生物氧化过程中蓝晶石的(反式)形成及其对P的去向的影响；(3)确定Fe(III)与硫酸盐还原细菌共存时Fe(III)磷酸盐矿物的(反式)形成及其对P的去向的影响；(4)确定循环氧化还原条件下铁矿物的生成及其对自然环境氧化还原转变过程中磷的形态和归宿的影响。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。