Article
Engineering, Environmental
Lin Wang, Songhao Shang, Wenzhi Liu, Dongli She, Wei Hu, Yi Liu
Summary: The study investigated the variation of nitrogen components in different aquatic ecosystems and found that nitrogen removal occurred during water flow, with a reduction rate of up to 43%. The heterogeneity in eco-stoichiometric characteristics of nitrogen components was higher in ditches and ponds compared to rivers and reservoirs. Ditches and ponds showed stronger interactions between overlying water and sediment, with higher rates of denitrification and anaerobic ammonium oxidation. The findings emphasize the importance of focusing on the upper reaches of agricultural catchments for nitrogen removal and developing region-specific conservation strategies to mitigate nitrogen pollution and protect water resources.
Article
Multidisciplinary Sciences
Christian Dewey, Patricia M. Fox, Nicholas J. Bouskill, Dipankar Dwivedi, Peter Nico, Scott Fendorf
Summary: Beaver dams have a greater impact on water residence time and oxygen and nitrogen fluxes in riparian subsurface than seasonal hydrologic extremes. With climate change, the expanding range of beavers will further alter watershed hydrology and biogeochemistry, illustrating that ecosystem feedbacks to climate change will change water quality in river systems.
NATURE COMMUNICATIONS
(2022)
Article
Soil Science
J. C. Dlamini, E. H. Tesfamariam, M. Verbeeck, N. Loick, A. Louro-Lopez, J. M. B. Hawkins, M. S. A. Blackwell, R. M. Dunn, A. L. Collins, L. M. Cardenas
Summary: Riparian buffers play a crucial role in improving water quality in agricultural landscapes, but the choice of vegetation and management practices can impact soil microbial communities and subsequently affect nutrient cycling and gas emissions. A study investigated the fluxes of nitric oxide (NO), nitrous oxide (N2O), nitrogen gas (N-2), and carbon dioxide (CO2) in soil samples collected from different types of riparian buffers. The results showed that grass riparian buffers had higher potential denitrification rates and were efficient in removing NO3-, while willow riparian buffers promoted complete denitrification to N-2, making them effective in areas with similar conditions.
SOIL USE AND MANAGEMENT
(2023)
Article
Engineering, Environmental
Qiwen Xia, Jiangtao He, Baonan He, Yanjia Chu, Wei Li, Jichao Sun, Dongguang Wen
Summary: Based on multiple regression analysis of 3245 shallow groundwater samples in the North China Plain, this study found that the distribution of groundwater total nitrogen (TN) is mainly influenced by attenuation and accumulation zones rather than soil nitrogen and intrinsic groundwater vulnerability. The attenuation zone is favorable to denitrification and has lower TN concentrations, while the accumulation zone has higher TN concentrations due to limited denitrification. The study highlights the importance of redox conditions in controlling groundwater TN pollution.
Article
Environmental Sciences
Paraskevi Mara, Virginia P. Edgcomb, Taylor R. Sehein, David Beaudoin, Chuck Martinsen, Christina Lovely, Bridget Belcher, Rebecca Cox, Meghan Curran, Claire Farnan, Peter Giannini, Sarah Lott, Kyle Paquette, Anna Pinckney, Natalie Schafer, Tonna-Marie Surgeon-Rogers, Daniel R. Rogers
Summary: The study found that oyster aquaculture plays a positive role in the removal of nitrogen from sediments, but different farming methods show variations in gene expression related to nitrogen cycling and nitrogen gas flux. Particularly, nitrogen retention process is significantly enhanced, especially under the bottom cages.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Ling-Zhi Zhang, Wei He, Fu-Yi Huang, Wei He, Pengpeng Zhou, Cuibai Chen, Christopher Rensing, Kristian Koefoed Brandt, Jiangtao He, Fei Liu, Yi Zhao, Huaming Guo
Summary: This study investigated the microbial community, nitrogen metabolic attributes, and their responses to NO3--N pollution in suburban groundwater in Beijing. The results showed that groundwater with higher NO3--N concentrations had lower microbial richness and abundance of N metabolic genes, and denitrification was the dominant N cycling process. The study also found significant associations between NO3--N, NH4+-N, microbial taxonomy, and N functional attributes.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Soil Science
Chen Chen, Leanne Ejack, Martin R. Chenier, Joann K. Whalen
Summary: Riparian buffers are important areas for nitrogen removal through denitrification, with earthworms playing a significant role in enhancing this process. This study in Quebec, Canada, found that flooded riparian soils had higher earthworm populations and biomass compared to non-flooded soils, with a positive correlation between certain earthworm functional groups and denitrifier activity. Soil moisture, inorganic N concentration, and earthworm functional groups were identified as predictors of denitrifier activity in riparian soils.
Article
Environmental Sciences
Yang Liu, Jia Xin, Yuan Wang, Zhixiang Yang, Shixuan Liu, Xilai Zheng
Summary: This study investigates the effects of different types of dissolved organic nitrogen (DON) on nitrate accumulation in groundwater and reveals the complex roles DON plays in nitrogen cycling processes. The researchers established quantitative correlations between microbial indicators and nitrogen content. The findings provide guidance for environmental risk evaluation and control strategies for nitrate pollution in groundwater.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Yu Gong, Chen Ye, Quanfa Zhang
Summary: This study investigates the effects of restoration approaches and hydrological changes on carbon and nitrogen cycling in degraded riparian ecosystems. The results show that compared to natural regeneration, active revegetation did not affect vegetation and microbial diversity, but decreased soil ammonium and total carbon contents. The flooding zone had a more significant impact than the restoration approach, with the extreme flooding zone showing the highest denitrification rates and CO2 fluxes.
Article
Agronomy
Zheyu Xie, Yujing Zhang, Zhenyu Zhang, Jinliang Huang
Summary: A study in Southeast China reveals that the transition zone between rivers and riparian aquifers plays a crucial role in removing nitrate contamination from aquatic systems. The high connectivity between rivers and groundwater enhances the potential for nitrate removal. The study also highlights the significant contributions of manure and sewage, as well as soil and chemical fertilizers, to nitrate contamination.
AGRICULTURAL WATER MANAGEMENT
(2023)
Article
Environmental Sciences
Shreeram P. Inamdar, Erin K. Peck, Marc Peipoch, Arthur J. Gold, Melissa Sherman, Johanna Hripto, Peter M. Groffman, Tara L. E. Trammell, Dorothy J. Merritts, Kelly Addy, Evan Lewis, Robert C. Walter, Jinjun Kan
Summary: This study reveals that the legacy of milldams and road salts can undermine the nitrogen buffering capacity of riparian zones, resulting in significant nitrogen pollution. The findings emphasize the need to consider the compounding effects of anthropogenic legacies in watershed management and decision-making processes regarding dam removal.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Soil Science
Meimei Li, Matthew D. Petrie, Hao Chen, Fanjiang Zeng, Zeeshan Ahmed, Xibin Sun
Summary: This study investigates the effects of groundwater depth and distance to a seasonally active river on the nitrogen fixation rate of Alhagi sparsifolia, a dominant deep-rooted legume species in the southern fringe of the Taklimakan Desert. The results show that the nitrogen fixation rate of A. sparsifolia decreases with groundwater depth and increases with distance from the river channel. It is found that the spatial pattern in nitrogen fixation is mainly regulated by the salinity gradient formed by groundwater flow and streamflow.
Article
Environmental Sciences
Chunjian Lyu, Xiaojie Li, Huibin Yu, Yonghui Song, Hongjie Gao, Peng Yuan
Summary: In this study, the researchers monitored the potential nitrification rate, denitrification potential, and net N2O production rate in riparian soils, and used metagenomic sequencing to understand the mechanism of microbial N removal. The riparian soils showed a strong denitrification process, with higher rates of denitrification than nitrification and N2O production. Near farmland edges, the rates of denitrification, nitrification, and N2O production were lower. The composition of the N-cycling microbial community varied between different soil depths.
ENVIRONMENTAL RESEARCH
(2023)
Article
Microbiology
Fei Ye, Lei Duan, Yaqiao Sun, Fan Yang, Rui Liu, Fan Gao, Yike Wang, Yirong Xu
Summary: This study used molecular biotechnology, microcosm culture experiments, and N-15 stable isotope tracing techniques to investigate the nitrogen removal mechanism of a riparian zone with a multi-layer lithologic structure. The results revealed that denitrification, dissimilatory reduction to ammonium (DNRA), and anaerobic ammonium oxidation (anammox) were the main nitrogen transformation processes occurring in the riparian zone. Factors such as sedimentary NOX-, Fe(II), dissolved organic carbon (DOC), and microbial abundance played important roles in nitrogen removal. The findings of this study have practical implications for riparian zone management and the prevention and control of global nitrogen pollution.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Environmental Sciences
Danli Deng, Bangjing Ding, Gang He, Mingfei Ji, Yuyi Yang, Guihua Liu, Quanfa Zhang, Wenzhi Liu
Summary: This study demonstrates that denitrification and anammox rates are significantly higher in rhizosphere soils compared to bulk soils, indicating that the rhizosphere environment is favorable for nitrogen removal. Anammox constitutes over half of the nitrogen loss, with higher rates observed in bulk soils than in rhizosphere soils. Therefore, revegetation can effectively enhance the nitrogen removal function of riparian wetlands along the Yangtze River.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Ecology
Valerie Ouellet, Melinda D. Daniels, Marc Peipoch, Laura Zgleszewski, Nathan Watson, Emma Gibson, Stefan Krause, Jin Jun Kan
Summary: Microbial community composition in stream pools is influenced by substrate stability, with heterotrophic bacteria dominating soft sediments and photosynthetic microorganisms mainly found on rock biofilm. The distribution of bacterial communities is explained by variations in local hydraulic and thermal conditions. Incorporating these drivers into stream restoration practices can enhance microbial diversity and ecosystem functions.
Article
Biodiversity Conservation
Mario Brauns, Daniel C. Allen, Iola G. Boechat, Wyatt F. Cross, Veronica Ferreira, Daniel Graeber, Christopher J. Patrick, Marc Peipoch, Daniel Schiller, Bjoern Guecker
Summary: Human impacts, such as nutrient pollution and land-use change, have led to declines in the quality and quantity of freshwater resources. This study analyzes the effects of human stressors on stream ecosystem functions and finds that most stressors inhibit ecosystem functioning. Nitrate uptake efficiency is particularly affected, with agriculture having the largest inhibitory effect. However, there are both negative and positive effects within each stressor-function pair. Wastewater effluents, agriculture, and urban land use have the strongest overall effects. These findings highlight the importance of understanding the multifunctionality of streams and rivers and the need for ecological function-based freshwater management strategies.
GLOBAL CHANGE BIOLOGY
(2022)
Article
Ecology
H. Maurice Valett, Marc Peipoch, Geoffrey C. Poole
Summary: This study introduces the concept of nutrient processing domains (NPDs), which integrates routing and local processes to explain the longitudinal patterns of lotic biogeochemical function in rivers.
FRESHWATER SCIENCE
(2022)
Article
Environmental Sciences
Diana Oviedo-Vargas, Marc Peipoch, Charles Dow
Summary: This study investigates the diel dynamics of dissolved organic carbon (DOC) and nitrate (NO3-) concentrations in a third-order stream in Pennsylvania, USA. The diel variation is primarily influenced by stream metabolism and streamflow, with the underlying controls varying depending on the seasonality and viscosity effects of the streamflow.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Ecology
Marc Peipoch, Pete B. Davis, H. Maurice Valett
Summary: This study uses LiDAR data and hydrologic modeling to assess the biophysical complexity and productivity of floodplain forests. The results show that inundation has direct effects on canopy cover and vegetation productivity, while vegetation structural diversity plays an important mediating role. The coexistence of vegetation layers in floodplain patches enhances aboveground productivity in response to flooding regime.
Article
Environmental Sciences
Johanna Hripto, S. Inamdar, M. Sherman, E. Peck, A. J. Gold, S. Bernasconi, K. Addy, M. Peipoch
Summary: This study provides empirical data on the potential effects of relic low-head dams on stream nitrogen removal, suggesting limited impacts on stream ecosystems.
Article
Environmental Sciences
Melissa Sherman, Johanna Hripto, Erin K. Peck, Arthur J. Gold, Marc Peipoch, Paul Imhoff, Shreeram Inamdar
Summary: The study found that milldams have significant impacts on riparian groundwater gradients, flow directions, and mixing regimes, which vary under different hydrological conditions.
WATER RESOURCES RESEARCH
(2022)
Article
Microbiology
Jing Wang, Marc Peipoch, Xiaoxiao Guo, Jinjun Kan
Summary: Biofilm communities play a crucial role in explaining the temporal variation of biogeochemical conditions in freshwater ecosystems. However, little is known about the changes and successional trajectories of these complex microbial communities over time and from different initial conditions. This study used DNA high-throughput sequencing to monitor biofilm communities in a headwater stream during summer and winter, and found significant differences in biofilm composition based on the season and initiation time. Despite these differences, the biofilm community structures converged after 70 days, indicating the presence of a stable, mature community in the stream.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Environmental Sciences
Erin K. Peck, Shreeram Inamdar, Melissa Sherman, Johanna Hripto, Marc Peipoch, Arthur J. Gold, Kelly Addy
Summary: Riparian zones play a key role in buffering aquatic ecosystems through removal of nitrogen via processes like denitrification. This study investigated how dams affect riparian nitrogen cycling and buffering capacity. The results indicate that denitrification mainly occurs in shallow sediments with hydrological variability, while deeper sediments have lower denitrification rates and nitrate-nitrogen concentrations. Removing dams may improve riparian nitrogen buffering.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Environmental Sciences
Erin K. Peck, Shreeram P. Inamdar, Marc Peipoch, Arthur J. Gold
Summary: Riparian zones play a crucial role in regulating nutrient flux between terrestrial and aquatic ecosystems. Dams, however, can significantly alter the characteristics of riparian zones, trapping sediment and creating low-oxygen conditions, thereby affecting sediment biogeochemistry in ways that are not yet fully understood.
JOURNAL OF SOILS AND SEDIMENTS
(2023)
Article
Soil Science
Shreeram P. P. Inamdar, Sujay S. S. Kaushal, Robert Brian Tetrick, Larry Trout, Richard Rowland, Dennis Genito, Harsh Bais
Summary: Soil health is not considered in current stream and floodplain restorations, which may hinder their full restoration and ecological benefits. The lack of procedures and metrics for evaluating soil health is a major reason for its exclusion in floodplain restorations. This study provides a blueprint for including soil health, emphasizing easily accessible approaches for practitioners, and presents the challenges, metrics, and practices for improving floodplain soil health.
Article
Urban Studies
Jesse M. Engebretson, Kristen C. Nelson, Kelli L. Larson, Riley Andrade, Megan M. Wheeler, Susannah B. Lerman, Dexter H. Locke, Tara L. E. Trammell, Peter M. Groffman
Summary: This research examines the language of yard management policies in the U.S. and finds that ordinances can be both ambiguous and clear in different aspects. While they are clear regarding plant species and dimensions of impervious surfaces, they are ambiguous when it comes to the state or quality of the yard. These findings have important policy implications, especially considering the potential for subjective judgment and discriminatory enforcement, particularly in marginalized communities.
JOURNAL OF URBAN AFFAIRS
(2023)
