Article
Environmental Sciences
Maria Pia Gervasio, Elisa Soana, Fabio Vincenzi, Giuseppe Castaldelli
Summary: Denitrification in the Po River Delta plays a crucial role in attenuating nitrate pollution, accounting for approximately 30% of the daily nitrogen load.
Article
Engineering, Environmental
Feiyang Chen, Yanling Zheng, Lijun Hou, Yuhui Niu, Dengzhou Gao, Zhirui An, Jie Zhou, Guoyu Yin, Hongpo Dong, Ping Han, Xia Liang, Min Liu
Summary: The study revealed the distribution pattern and controlling factors of nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) bioprocesses in estuarine and intertidal marshes. It showed that Candidatus 'Methylomirabilis oxyfera'-like DAMO bacteria and Candidatus 'Methanoperedens nitroreducens'-like DAMO archaea cooccurred, with higher abundance of the M. oxyfera-like bacteria and a positive correlation with sediment pH and ammonium content.
Article
Engineering, Environmental
Xiaofei Li, Dengzhou Gao, Ye Li, Yanling Zheng, Hongpo Dong, Xia Liang, Min Liu, Lijun Hou
Summary: This study investigated the mechanisms of nitrous oxide (N2O) production in estuarine and coastal sediments under elevated nitrogen concentration using microbial inhibition, isotope mass balance, and molecular approaches. The results showed that increasing nitrate concentration led to changes in N2O production pathways and enhanced contributions from fungal denitrification and chemodenitrification. Moreover, elevated nitrate concentration also influenced the structure and abundance of nirK-type denitrifiers, which play a key role in N2O production.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Environmental Sciences
Na Li, Yong Li, Ruitao Lou, Hong Xu, Laraib Saeed
Summary: This study analyzed the effects of Fe(II) and organic carbon on nitrate reduction processes in lake sediments. The results showed that Fe(II) greatly promoted nitrate reduction at high temperatures, while the reduction rate decreased at low temperatures. The presence of organic carbon in sediments also influenced the nitrate reduction processes. Overall, the combination of Fe(II) and organic carbon played a significant role in nitrate reduction and nitrogen removal in lake systems.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Environmental Sciences
Chen Chen, Anniet M. Laverman, Celine Roose-Amsaleg, Garance Regimbeau, Khalil Hanna
Summary: This study investigates the transport of antibiotics ciprofloxacin and tetracycline in sediment from the Seine Estuary in France. The results show that although these antibiotics strongly interact with sediment components, they retain their antimicrobial activities. The major removal processes are found to be adsorption and abiotic degradation, while microbe-driven transformation is less significant.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Limnology
Song Li, Robert R. Twilley, Aixin Hou
Summary: The study revealed that increasing nitrate concentrations shifted the dominance of N-2 fixation to denitrification in benthic nitrogen cycling. While high nitrate levels reduced N-2 fixation rates, they did not completely inhibit N-2 fixation, especially in sites with higher sediment organic matter concentrations.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Engineering, Environmental
Jialin Chen, Ruina Zhang, Dong Chen, Jianyong Liu, Shanping Chen
Summary: The UV-enhanced generation of CO radical in the Fe(III)-oxalate system improves nitrate reduction to nitrogen with increased product selectivity. pH plays a key role in the NO reduction process, and higher concentrations of Fe(III) and oxalate promote NO3- removal and N-2 production.
JOURNAL OF WATER PROCESS ENGINEERING
(2021)
Article
Engineering, Marine
Hamed Jalil-Masir, Rohollah Fattahi, Elham Ghanbari-Adivi, Mahdi Asadi Aghbolaghi
Summary: This research examined the impact of coastal forest cover on sediment transport through experimentation and equation modeling. Results indicated that different cover densities can significantly influence sediment transport rates, with optimal density limits identified. The effects of configuration on cover efficiency were also investigated, highlighting the superiority of the zigzag arrangement over the aligned pattern.
Article
Microbiology
Nicole Dopffel, James Jamieson, Casey Bryce, Prachi Joshi, Muammar Mansor, Adam Siade, Henning Prommer, Andreas Kappler
Summary: Through cultivation experiments and biogeochemical modeling analysis, we found that below 30 degrees Celsius, biologically driven Fe(II) oxidation largely dominates overall Fe(II) oxidation, while abiotic Fe(II) oxidation by nitrite plays a less significant role.
FEMS MICROBIOLOGY ECOLOGY
(2021)
Article
Biotechnology & Applied Microbiology
Jianrong Huang, Mingxian Han, Jian Yang, Andreas Kappler, Hongchen Jiang
Summary: NRFeOx microorganisms are widely distributed and play an important role in iron transformation, nitrate, and heavy metal removal in various environments. However, their identity and activity under hypersaline conditions are still unknown. In this study, we analyzed the abundance and community compositions of NRFeOx microorganisms from five lake sediments with different salinities. The results showed that the abundance of NRFeOx microorganisms decreased with increasing salinity, and the community compositions varied among different lakes and were closely related to lake salinity.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2022)
Article
Geochemistry & Geophysics
Guoyong Huang, Xiaonan Wang, Dandan Pan, Guang Yang, Ruilin Zhong, Rumiao Niu, Bingqing Xia, Kuan Cheng, Tongxu Liu, Xiaomin Li
Summary: This study investigated the immobilization of cadmium (Cd) during nitrate-reducing Fe(II) oxidation (NRFO) and its impacts on the process. The results showed that higher initial Cd concentration led to a higher amount of Cd immobilized in precipitates but inhibited nitrate reduction, acetate metabolism, and cell growth. Cd had a minimal effect on Fe(II) oxidation during NRFO but slowed down the mineral transformation. Cd was found to be strongly co-localized with Fe on the surface of bacterial cells. Cd immobilization experiments indicated that both bacterial cells and secondary minerals were important for Cd immobilization. The findings provide important insights into the behavior and interactions of Cd during the NRFO process.
Article
Limnology
Thomas W. Brooks, Kevin D. Kroeger, Holly A. Michael, Joanna K. York
Summary: Nutrient loads delivered to estuaries via submarine groundwater discharge play a key role in the nitrogen budget and eutrophication status. Biogeochemical transformations within reactive estuarine surface sediment are a dominant driver in modifying the nitrogen flux carried upward by SGD. Seasonal shifts in the relative importance of biogeochemical processes alter the composition of the flux to estuarine surface water.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Plant Sciences
Yinghui Jiang, Shirong Zhang, Xiaodong Ding
Summary: The redox reaction between nitrate (NO3-) and Fe(II) plays a crucial role in the denitrification loss of nitrogen (N) in paddy soil. The impact of organic carbon in this process was examined by adding lactate and acetate. Lactate inhibited Fe(II) oxidation while acetate promoted it. In S1 soil, exogenous organic carbon accelerated NO3- reduction, but had no significant effect in S2 soil. Lactate reduced N loss by competing with Fe(II) as an electron donor, while acetate promoted Fe(II) oxidation as a carbon source.
JOURNAL OF SOIL SCIENCE AND PLANT NUTRITION
(2023)
Article
Biotechnology & Applied Microbiology
Jianrong Huang, Adrian Mellage, Julian Pavon Garcia, David Gloeckler, Susanne Mahler, Martin Elsner, Natalia Jakus, Muammar Mansor, Hongchen Jiang, Andreas Kappler
Summary: Autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms play a crucial role in carbon, iron, and nitrogen cycles. The study showed that the distribution of electrons from Fe(II) oxidation to either CO2 fixation or nitrate reduction deviated from the theoretical value. N2O was the main denitrification product. Furthermore, the Fe/N ratios influenced the distribution of electrons and the degree of cell-mineral interactions.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Wangting Yang, Weiqi Wang, Lidong Shen, Yanan Bai, Jiaqi Liu, Yuling Yang, Hechen Huang, Bingjie Ren
Summary: By investigating four coastal wetlands in southeast China, we found that regional and local environmental conditions, as well as plant species cover, have an impact on nitrate-driven anaerobic oxidation of methane (AOM) activity and ANME-2d archaeal community. This study reveals the potential of this process in reducing methane emissions in wetlands and the influence of environmental factors.
Review
Biology
Eric Alexander Runge, Muammar Mansor, Andreas Kappler, Jan-Peter Duda
Summary: Deep-sea hydrothermal systems are important for the emergence of life, but the distribution and diversity of microbial communities in ancient systems are still unclear. Understanding the formation and preservation of microbial biosignatures in these systems is challenging and requires multidisciplinary studies.
Article
Biotechnology & Applied Microbiology
Jianrong Huang, Adrian Mellage, Julian Pavon Garcia, David Gloeckler, Susanne Mahler, Martin Elsner, Natalia Jakus, Muammar Mansor, Hongchen Jiang, Andreas Kappler
Summary: Autotrophic nitrate-reducing Fe(II)-oxidizing microorganisms play a crucial role in carbon, iron, and nitrogen cycles. The study showed that the distribution of electrons from Fe(II) oxidation to either CO2 fixation or nitrate reduction deviated from the theoretical value. N2O was the main denitrification product. Furthermore, the Fe/N ratios influenced the distribution of electrons and the degree of cell-mineral interactions.
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Engineering, Environmental
Guoqiang Zhao, Mengxi Tan, Binbin Wu, Xiaoshan Zheng, Ruoxuan Xiong, Baoliang Chen, Andreas Kappler, Chiheng Chu
Summary: Tidal-induced redox oscillations can activate thermodynamically stable iron minerals into a metastable phase for enhanced ROS production.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
Qian Zheng, Shuxin Tu, Yiwen Chen, Hongjun Zhang, William Hartley, Bangjiao Ye, Lu Ren, Juan Xiong, Wenfeng Tan, Andreas Kappler, Jingtao Hou
Summary: This study investigates the adsorption behavior of As(III) and As(V) on ferrihydrite. The results show that ferrihydrite has a higher affinity for As(III) and contains abundant micropores that contribute to the immobilization of As(III).
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Multidisciplinary Sciences
Tori M. Hoehler, Dylan J. Mankel, Peter R. Girguis, Thomas M. McCollom, Nancy Y. Kiang, Bo Barker Jorgensen
Summary: We investigated the connection between biological energy utilization rates and the biomass sustained by this energy utilization at both organism and biosphere levels. By compiling a dataset consisting of over 10,000 measurements of metabolic rates from more than 2,900 species, and quantifying energy utilization rates on a biomass-normalized basis for different components of the biosphere, we found that energy utilization rates vary greatly. The correlation between mass-normalized energy utilization rates and biomass carbon turnover rates suggests global mean turnover rates for terrestrial soil biota, marine water column biota, and marine sediment biota.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Jannik Martens, Carsten W. Mueller, Prachi Joshi, Christoph Rosinger, Markus Maisch, Andreas Kappler, Michael Bonkowski, Georg Schwamborn, Lutz Schirrmeister, Janet Rethemeyer
Summary: In Siberian permafrost sediments deposited during the Pleistocene, the presence of reactive iron leads to the mineral-bound organic carbon, which reduces microbial CO2 production after thawing. Rapid thaw of ice-rich Pleistocene-age permafrost can expose a large pool of organic matter to microbial degradation and greenhouse gas emissions, but protective physico-chemical mechanisms may restrict microbial accessibility and reduce decomposition, influenced by changing environmental conditions during sediment deposition. Study of different organic matter fractions in Siberian permafrost deposited during colder and warmer periods reveals that carbon preservation in mineral-associated organic matter is enhanced by reactive iron minerals, while warmer and wetter conditions reduce organic matter stabilization and increase CO2 production. The stability and bioavailability of Pleistocene-age permafrost carbon are important for predicting future climate-carbon feedback.
NATURE COMMUNICATIONS
(2023)
Article
Engineering, Environmental
Yuge Bai, Tianran Sun, Muammar Mansor, Prachi Joshi, Yiling Zhuang, Stefan B. Haderlein, Stefan Fischer, Kurt O. Konhauser, Daniel S. Alessi, Andreas Kappler
Summary: In this study, the roles of dissolved organic matter (DOM) and organo-mineral associations (OMAs) in electron transfer were investigated during microbial Fe-(III)-mineral reduction. Only when both DOM and OMAs were present, significant electron transfer occurred. The proportion of DOM and OMAs showed a positive correlation with the extent of Fe-(III) mineral reduction, but the variation in DOM proportion had a stronger effect on the reduction compared to OMAs. These findings provide new insights into how organic carbon facilitates iron transformation and the associated biogeochemical cycling of nutrients and contaminants in forest soil systems.
ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS
(2023)
Article
Engineering, Environmental
Dandan Chen, Kuan Cheng, Tongxu Liu, Guojun Chen, Andreas Kappler, Xiaomin Li, Raymond Jianxiong Zeng, Yang Yang, Fujun Yue, Shiwen Hu, Fang Cao, Fangbai Li
Summary: This study demonstrates that dual N-O isotopes and kinetic modeling can be used to distinguish biological and chemical processes during microbially mediated NRFO. The main nitrate reductase in Acidovorax sp. strain BoFeN1 was found to be membrane-bound dissimilatory nitrate reductase (Nar). N-O isotopes can be used to differentiate between chemical and biological reactions, and chemodenitrification plays a more important role than biological reactions during the coupled process.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Juan Liu, Yongjin Xiang, Yiwen Chen, Hongjun Zhang, Bangjiao Ye, Lu Ren, Wenfeng Tan, Andreas Kappler, Jingtao Hou
Summary: This study synthesized hematite samples with tunable oxygen vacancy defect (OVD) concentrations and investigated their effects on arsenate adsorption. The results revealed that oxygen vacancy was the primary defect type on the hematite surface. Quantitative relationships between OVD concentration and enhanced arsenate adsorption were established. NH3-DRIFT analysis and DFT calculations demonstrated the beneficial role of OVDs in improving adsorption strength and promoting arsenate immobilization.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Zhao-Feng Yuan, Yujie Zhou, Zheng Chen, Tong Zhang, Andreas Kappler, Williamson Gustave, Xianjin Tang, Jianming Xu
Summary: A new sustainable method using man-made aerenchymatous tissues (MAT) to increase soil redox potential (Eh) and reduce arsenic accumulation in rice paddies has been proposed and verified.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Environmental
Bobo Xing, Nigel J. D. Graham, Binghao Zhao, Xian Li, Youneng Tang, Andreas Kappler, Hailiang Dong, Mari Winkler, Wenzheng Yu
Summary: Biomineralization occurring in the bacterial periplasmic space enhances electron transfer. Denitrification-driven Fe(II) oxidation plays a crucial role in connecting iron and nitrogen cycling in the environment. This study investigated the pathways and effects of iron entering the periplasmic space of the denitrifier Pseudomonas sp. JM-7, providing insights into the microbial metabolism and electron transfer in relation to iron presence.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Review
Microbiology
Laurent Philippot, Claire Chenu, Andreas Kappler, Matthias C. Rillig, Noah Fierer
Summary: Considerable progress has been made in recent years in determining the soil properties that influence the structure of the soil microbiome. However, the effects of microorganisms on their soil habitat have received less attention. Microorganisms not only contribute to nutrient cycling and organic matter transformations, but also alter the soil habitat through various mechanisms. Understanding the interactions between microorganisms and soil properties can have significant ecological implications.
NATURE REVIEWS MICROBIOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Timm Bayer, Ran Wei, Andreas Kappler, James M. Byrne
Summary: The adsorption capacity and overall efficiency of mixed-valent magnetite nanoparticles (MNPs) for heavy metal pollutants are influenced by their redox state and surface charge, which are affected by microbial redox cycling of iron (Fe) in magnetite and changes in pH. Microbial modification of MNPs has an important impact on the adsorption of Cu2+ and Cd2+, and a change in stoichiometry of the MNPs can have a greater influence than a change of pH.
ACS EARTH AND SPACE CHEMISTRY
(2023)
Article
Environmental Sciences
Lu Lu, Saskia Rughoeft, Daniel Straub, Samantha B. B. Joye, Andreas Kappler, Sara Kleindienst
Summary: This study provides evidence that the biosurfactant rhamnolipid is more efficient than the chemical dispersants Corexit 9500 and Slickgone NS in stimulating oil biodegradation in natural seawater. The impacts of biosurfactants on microbial community composition and oil biodegradation activities were examined using time-course microcosm experiments. The results showed high hydrocarbon oxidation rates and microbial activities in the rhamnolipid-amended oil microcosms. The findings suggest that biosurfactants have great promise for future marine oil spill responses.
Article
Environmental Sciences
Anh Van Le, E. Marie Muehe, Sharon Bone, Soren Drabesch, Stefan Fischer, Andreas Kappler
Summary: Household sand filters (SFs) are commonly used to remove groundwater contaminants in low-income regions. This study investigated the removal of Fe, As, and Mn under unsaturated and saturated conditions. The results showed effective removal of Fe and As under both conditions, while leaching of Mn occurred under saturated conditions. The presence of Mn(IV) oxides during unsaturated conditions played a significant role in the oxidation and removal of Fe and As.