Iron reduction promotes carbon mineralization and nutrient release of iron-associated organic matter in anoxic environments

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-06-16 DOI:10.1016/j.watres.2025.124032

Liang Yang, Yuanchun Zou, Zhongjun Jia, Yu Luo, Lei Qin, Ming Jiang, Zicheng Yu

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引用次数: 0

Abstract

The association of dissolved organic matter (DOM) with minerals is critical for the protection and stabilization of organic matter in peatlands, yet the stabilization of mineral-associated DOM and its role in nutrient supply remain poorly understood. Here we conducted incubation experiments to investigate the stability of synthesized ferrihydrite-associated DOM (Fh-DOM) under oxic and anoxic conditions. The DOM from Fh-DOM and inoculated microbial consortia were extracted from fen and bog peats that have different redox conditions. Our results showed that carbon (C) mineralization of Fh-DOM under anoxic conditions was approximately 5-fold higher than that under oxic conditions, because of iron reduction under anoxic conditions. Surprisingly, the bog incubations exhibited a higher proportion of C mineralization from Fh-DOM (14.1 ± 0.1%) than that of the fen incubations (4.1 ± 0.3%), despite having less active iron reduction in the bog incubations. This difference was attributed to a higher proportion of protein-like fluorophores (17.7%) in Fh-DOM of the bog incubations, which act as an effective nutrient to promote bacterial growth. In addition, the enhancement of potential C metabolic functions in the bog incubations under anoxic conditions was significantly higher than that in the fen incubations. The effect of iron reduction on C mineralization mostly comes indirectly through microbial respiration of disassociated Fh-DOM (over 70%), rather than directly from redox reaction itself. Furthermore, Fh-DOM addition under anoxic conditions enhanced bacterial community stability in the both fen and bog incubations by increasing the number and abundance of key species in the microbial networks, which are primarily linked to nutrient-mining functions. Our study highlights the prevalent but overlooked role of mineral-associated DOM as a nutrient source for microbes under anoxic conditions, providing new insights into stabilization and destabilization mechanisms of organic matter in peatlands and other anoxic environments.

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在缺氧环境下，铁还原促进了铁相关有机质的碳矿化和养分释放

溶解有机质（DOM）与矿物质的关联对于泥炭地有机质的保护和稳定至关重要，但与矿物质相关的DOM的稳定及其在营养供应中的作用仍然知之甚少。在此，我们进行了孵育实验，研究了合成的水合铁相关DOM （Fh-DOM）在缺氧和缺氧条件下的稳定性。从具有不同氧化还原条件的泥炭和泥炭中提取Fh-DOM和接种菌群中的DOM。我们的研究结果表明，缺氧条件下Fh-DOM的碳(C)矿化比缺氧条件下高约5倍，这是由于缺氧条件下铁的还原。令人惊讶的是，尽管沼泽培养的活性铁还原较少，但沼泽培养的Fh-DOM的C矿化比例（14.1±0.1%）高于沼泽培养（4.1±0.3%）。这一差异归因于沼泽培养皿中Fh-DOM中蛋白质样荧光团的比例较高（17.7%），它们是促进细菌生长的有效营养物质。此外，缺氧条件下沼泽培养对C势代谢功能的增强显著高于沼泽培养。铁还原对C矿化的影响主要通过微生物呼吸作用（超过70%）间接产生，而不是直接来自氧化还原反应本身。此外，在缺氧条件下添加Fh-DOM通过增加微生物网络中关键物种的数量和丰度，增强了沼泽和沼泽培养中细菌群落的稳定性，这主要与营养挖掘功能有关。我们的研究强调了矿物质相关的DOM作为缺氧条件下微生物的营养来源的普遍但被忽视的作用，为泥炭地和其他缺氧环境中有机物的稳定和不稳定机制提供了新的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.