Article
Geochemistry & Geophysics
Yaoxuan Chen, Xiaosi Su, Yuyu Wan, Hang Lyu, Weihong Dong, Yakun Shi, Yiwu Zhang
Summary: River eutrophication and nitrogen pollution pose a potential threat to groundwater quality in riverbank filtration systems. This study used hydrogeochemical and stable isotope tracing techniques to investigate the geochemical reactions controlling nitrogen migration and transformation during riverbank filtration in a typical site in NE China. The results revealed that mixing, adsorption, organic nitrogen mineralization, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA) are the main geochemical reactions. Denitrification primarily occurs close to the riverbed surface and accounts for NO3- attenuation, while DNRA is more active at a certain depth and plays a significant role in NH4+ enrichment.
APPLIED GEOCHEMISTRY
(2022)
Article
Environmental Sciences
Dan Wang, Peiyue Li, Dawei Mu, Weichao Liu, Yinfu Chen, Misbah Fida
Summary: This study investigates the biogeochemical processes of nitrate in the vadose zone-groundwater system using hydrogeochemistry, stable isotopes, and microbial techniques. The results indicate that nitrate concentration is influenced by plant root absorption, assimilation, and nitrification processes. Denitrification mainly occurs in the 60-80 cm soil layer. The microbial community structure is affected by soil sampling depths and groundwater nitrate concentrations. The study provides important insights for understanding and managing groundwater nitrogen in agricultural areas.
SCIENCE OF THE TOTAL ENVIRONMENT
(2024)
Article
Biodiversity Conservation
Jacob S. Diamond, Susana Bernal, Amine Boukra, Matthew J. Cohen, David Lewis, Matthieu Masson, Florentina Moatar, Gilles Pinay
Summary: An explosion in high frequency dissolved oxygen (DO) observations at river network scales is providing new opportunities to understand dynamic signals in streams and rivers. Simple DO metrics are useful proxies of stream metabolism, capturing key features of its spatiotemporal variation, and predicting patterns in dissolved organic matter quality and catchment nitrogen processing via denitrification. However, DO metrics were less successful as proxies for ecosystem respiration, and the relationships with dissolved organic matter quality and denitrification were stronger than those with gross primary production or ecosystem respiration.
ECOLOGICAL INDICATORS
(2021)
Article
Soil Science
Yuxuan Wan, Qing Du, Yue Wu, Ruixiang Li, Xuejun Yan, Nan Li, Xin Wang
Summary: Large amounts of nitrogen fertilized to food production are lost via denitrification and leaching. Dissimilatory nitrate reduction to ammonium (DNRA) is a bioprocess competing with denitrification, and it conserves bioavailable nitrogen in soil ecosystems. Our results found a sustainable way of nitrogen retention in soils, and have broader implications for understanding nitrogen turnover in ecosystems.
SOIL BIOLOGY & BIOCHEMISTRY
(2023)
Article
Environmental Sciences
Feng Sun, Qinghui Deng, Xiaowen Li, Mengjuan Tang, Xufa Ma, Xiuyun Cao, Yiyong Zhou, Chunlei Song
Summary: The study found that high organic carbon content in matrix facilitated dissimilatory nitrate reduction to ammonium (DNRA) over denitrification (DEN), while low organic carbon content promoted DEN. It was also observed that using corn cob as OC source in biofilters was more effective than bagasse due to slow and continuous release of organic carbon. Choosing suitable OC source and regulating its dosage are crucial for enhancing nitrate removal and reducing ammonium accumulation in biofilters.
Article
Environmental Sciences
Yan Huang, Soonmo An
Summary: This study examined the effects of seasonal hypoxia on nitrogen transformations at the sediment-water interface in Jinhae Bay. The results showed that denitrification increased, anammox ceased, and DNRA decreased during hypoxia. Sediments acted as a sink for nitrate during hypoxia. The dominance of DNRA may contribute to eutrophication and seasonal hypoxia in this system.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Rauno Lust, Jaak Nerut, Sharvari S. Gadegaonkar, Kuno Kasak, Mikk Espenberg, Triinu Visnapuu, Uelo Mander
Summary: Microbial electrosynthesis is a promising solution for removing low concentrations of nitrate from water. The study found that the design of a single-chamber reactor saves on construction costs and provides more stable pH levels in the solution. The optimal electrode potential achieved the highest Faradaic efficiency and nitrate removal rate. Additionally, the process was driven by denitrification, and the microbial electrosynthesis reactor can be effectively used to purify water sources when adding organic compounds as electron donors is not feasible.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2022)
Article
Soil Science
Xin Fang, Zhishu Yang, Jiangang Han
Summary: This study investigated the effects of different vegetation belts and seasonal changes on DNF, DNRA, and bacterial community structure in a coastal wetland. The results showed that DNRA was the dominant process in NO3- reduction in this wetland, and the DNRA/DNF ratios were positively correlated with soil NO3- concentrations.
APPLIED SOIL ECOLOGY
(2022)
Article
Environmental Sciences
Shreeram Inamdar, Marc Peipoch, Arthur J. Gold, Evan Lewis, Johanna Hripto, Melissa Sherman, Kelly Addy, Dorothy Merritts, Jinjun Kan, Peter M. Groffman, Robert Walter, Tara L. E. Trammell
Summary: Milldams and their legacies have significant impacts on fluvial processes and geomorphology, but their effects on riparian nitrogen processing are less understood. The potential effects of existing and breached milldams on riparian nitrogen cycling are uncertain and require further investigation.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Xiaolong Yao, Zhonghua Zhao, Jianjun Wang, Qiqi Ding, Minglei Ren, Ismael Aaron Kimirei, Lu Zhang
Summary: The nitrogen transformation in East African lakes is mainly driven by benthic organic matter properties and water column phosphate concentrations, and the sediment nitrogen supply and loss can be improved by considering sediment organic matter properties.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Civil
Ya Wu
Summary: High levels of ammonium in the coastal acidic groundwater of Beihai, Southern China pose a threat to surface ecosystems and water supplies. A study was conducted using hydrochemical and isotopic analysis to investigate the occurrence of ammonium and its genesis. The findings suggest that dissimilatory nitrate reduction to ammonium plays a critical role in the enrichment of ammonium concentrations in groundwater.
JOURNAL OF HYDROLOGY
(2022)
Article
Agricultural Engineering
Shiyang Zhang, Longqu Xiao, Zhiwei Tang, Xiangling Zhang, Zhi Wang
Summary: This study investigated the fluctuating profiles of physicochemical and microbial characterizations along different filling heights of continuously up-flow solid-phase denitrification columns packed with PCL. It was found that both the PCL filling area and non-filling area significantly contributed to treatment performance, with denitrification mainly occurring near the bottom of the filling column. Nitrate showed high removal rates, while nitrite and ammonium displayed weak accumulation in final effluents.
BIORESOURCE TECHNOLOGY
(2022)
Article
Environmental Sciences
Xiaoling Li, Jianqiang Zhao, Yuhao Zhang, Jiaojie He, Kaili Ma, Chunshuang Liu
Summary: This study found that the proportion of DNRA increases in high-electron systems, particularly in organic-rich or sulfide-rich systems, indicating that excess electron donors favor DNRA. Additionally, a higher reductive environment also facilitates DNRA. 16S rRNA gene sequencing analysis revealed different participants involved in the DNRA process in organic-rich and sulfide-rich systems.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Microbiology
Shih-Yao Lin, Asif Hameed, Chia-Fang Tsai, Chiu-Chung Young
Summary: A Gram-stain-negative bacterium named Vineibacter terrae gen. nov., sp. nov. was isolated from vineyard soil in Taiwan. This bacterium is aerobic, non-motile, and capable of reducing nitrate, with optimal growth conditions at 30 degrees C and pH 7, belonging to the family Rhodospirillaceae.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY
(2021)
Article
Soil Science
Arjun Pandey, Helen Suter, Ji-Zheng He, Hang-Wei Hu, Deli Chen
Summary: This study found that unfertilized rice paddies maintain nitrogen status through microbial N(2) fixation and dissimilatory nitrate reduction to ammonium (DNRA), while high nitrogen input paddies tend to lose nitrogen through denitrification. Increasing the soil organic carbon-to-nitrate ratio can improve nitrate retention in high nitrogen input paddies.
BIOLOGY AND FERTILITY OF SOILS
(2021)
Article
Ecology
Aaron Macy, Michael J. Osland, Julia A. Cherry, Just Cebrian
Summary: Increases in temperature are expected to facilitate the encroachment of tropical mangrove forests into temperate salt marshes. The study conducted in Louisiana, USA, compared carbon and nitrogen stocks in marshes and mangroves and found that black mangrove encroachment leads to increased aboveground carbon and nitrogen stocks. However, belowground nitrogen and carbon sequestration may not be affected. Further studies are needed to better understand the implications of mangrove encroachment on nitrogen cycling, storage, and export to the coastal ocean.
Article
Ecology
Lorae T. Simpson, Julia A. Cherry, Rachel S. Smith, Ilka C. Feller
Summary: The study found that mangrove expansion may increase nutrient availability by increasing turnover of leaf litter, but it does not significantly alter the environmental factors driving decomposition. Differences in soil nutrient sources may vary between habitats due to shifts in foundation plant species.
Article
Ecology
Corianne Tatariw, Behzad Mortazavi, Taylor C. Ledford, Sommer F. Starr, Erin Smyth, Abigail Griffin Wood, Lorae T. Simpson, Julia A. Cherry
Summary: Human activities have led to a decrease in global salt marsh surface area, prompting the construction of marshes in terrestrial systems to mitigate this loss. While constructed marshes can rapidly recover ecosystem structure, the recovery of biogeochemical processes may be slow. Comparing denitrification and DNRA rates between excavation-created and natural reference salt marshes can help assess the recovery of ecosystem function.
RESTORATION ECOLOGY
(2021)
Article
Environmental Sciences
Sara Martin, Eric L. Sparks, Adam J. Constantin, Just Cebrian, Julia A. Cherry
Summary: The study shows that intermediate initial cover (50%) can restore plant cover and promote nitrogen removal at relatively lower labor and material costs, maximizing restoration outcomes in the face of low to moderate sea-level rise.
ENVIRONMENTAL MANAGEMENT
(2021)
Article
Agronomy
Susanne Wiesner, Gregory Starr, Lindsay R. Boring, Julia A. Cherry, Paul C. Stoy, Christina L. Staudhammer
Summary: Since the 1970s, the southeastern US has seen an increase in extreme heat events, partially attributed to global change. Despite rising temperatures, greater weather variability has also led to more freeze events in the region. Variations in forest stands and plant diversity can result in localized meteorological differences affecting different forests' recovery from temperature-induced disturbances. This variation influences energy and entropy dynamics, impacting the metabolic response of these systems.
AGRICULTURAL AND FOREST METEOROLOGY
(2021)
Article
Ecology
Aaron Macy, Michael J. Osland, Julia A. Cherry, Just Cebrian
Summary: The study suggests that planting mangroves in the northern Gulf of Mexico may not be the most efficient use of limited resources. Restoration efforts may benefit from focusing initially on restoring abiotic conditions, followed by using marsh plants to jump-start ecosystem development.
RESTORATION ECOLOGY
(2021)
Article
Environmental Sciences
Corianne Tatariw, Olivia U. Mason, Behzad Mortazavi
Summary: The constructed stormwater control systems can be biogeochemical hotspots, but their ecosystem structure may become homogenized due to construction and management. Roadside ditches, a common landscape feature, have high potential for nitrate removal with denitrification and anammox processes dominating. Although soil characteristics were similar between different land use types, denitrification potential rates were lower in forested ditches compared to urban and agricultural ditches, possibly due to differences in vegetation management. Microbial diversity was consistent across land use types, but indicator species analysis showed significant microbial groups in urban and agricultural ditches involved in nitrogen removal processes. Land use effects on nitrogen removal in these constructed drainage networks are mediated through key microbial groups and ditch vegetation management strategies, indicating significant potential for reactive nitrogen removal in the landscape.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2021)
Article
Environmental Sciences
Jonathan L. Pitchford, Kimberly Cressman, Julia A. Cherry, Brook T. Russell, Jay McIlwain, Michael J. Archer, William Underwood
Summary: This study examined the trends in surface elevation change and sediment accretion in the Grand Bay estuary of the Gulf of Mexico. The results showed that J. roemerianus marshes located at higher elevations were more vulnerable to sea level rise, while lower elevation marshes were driven by sediment accretion and biogenic inputs. The study also suggests that marsh migration may be a potential solution for marsh persistence in this relatively undeveloped area.
WETLANDS ECOLOGY AND MANAGEMENT
(2022)
Article
Soil Science
S. F. Starr, B. Mortazavi, C. Tatariw, K. A. Kuehn, J. A. Cherry, T. Ledford, E. Smyth, A. Griffin Wood, S. E. Sebren
Summary: The study found that 30 years after the construction of salt marshes, the denitrification rates and fungal denitrification contribution in constructed salt marshes are lower than in natural salt marshes. Fungal biomass may limit the recovery of nitrogen removal in constructed salt marshes.
SOIL BIOLOGY & BIOCHEMISTRY
(2022)
Editorial Material
Plant Sciences
Julia A. Cherry, Gregory J. Pec
APPLICATIONS IN PLANT SCIENCES
(2022)