Article
Green & Sustainable Science & Technology
Zhaolei Li, Zhaoqi Zeng, Zhaopeng Song, Dashuan Tian, Xingzhao Huang, Sheng Nie, Jun Wang, Lifen Jiang, Yiqi Luo, Jun Cui, Shuli Niu
Summary: This study provides insights into the geographical variations and primary controlling factors of global soil N2O emissions based on a new dataset of soil N2O emission rates compiled from field observations. It highlights the critical roles of soil N substrates on N2O emissions, contributing to the optimization of process-models for soil N2O emissions.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Oceanography
C. M. Payne, K. R. Arrigo
Summary: Changing sea ice conditions in the northern Chukchi Sea have led to an increase in net primary production (NPP) and under-ice phytoplankton blooms, resulting in higher particle export and sedimentary denitrification rates. This could have significant implications for the nitrogen cycle and downstream regions such as the Greenland Sea and North Atlantic.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
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
Mohit Masta, Mikk Espenberg, Sharvari S. Gadegaonkar, Jaan Parn, Holar Sepp, Kalle Kirsimae, Fotis Sgouridis, Christoph Mueller, Ulo Mander
Summary: Peatlands play a significant role in nitrous oxide (N2O) emissions, with bacterial denitrification being the primary source and nitrification as a secondary source. The study found that under intermediate and flooded conditions, ammonia oxidation was also a source of N2O, and dissimilatory nitrate reduction to ammonium (DNRA) potentially contributed to N2O emissions. The combination of isotopic and microbial analyses provided insights into the processes involved in N2O emissions.
Article
Environmental Sciences
Lamine Boumaiza, Safouan Ben Ammar, Romain Chesnaux, Randy L. Stotler, Bernhard Mayer, Frederic Huneau, Karen H. Johannesson, Jana Levison, Kay Knoeller, Christine Stumpp
Summary: This study investigates the sources and transformation processes of nitrate (NO3) contamination in a typical Mediterranean coastal agricultural area in Tunisia using multiple isotopic tracers and a Bayesian isotope MixSIAR model. The results show that the measured NO3 concentrations in groundwater are above the natural baseline threshold, indicating anthropogenic influence. The isotopic analysis suggests that manure, soil organic matter, and sewage are the potential sources of NO3, with manure-derived NO3 being the dominant source. The study also reveals the occurrence of denitrification and nitrification in the groundwaters, reflecting the complexity of interactions within the coastal aquifer.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Oceanography
Calvin W. Mordy, Lisa Eisner, Kelly Kearney, David Kimmel, Michael W. Lomas, Kathy Mier, Peter Proctor, Patrick H. Ressler, Phyllis Stabeno, Eric Wisegarver
Summary: This study investigates the nitrogen deficit on the eastern shelf of the Bering Sea and its influencing factors, concluding that spatial variability is influenced by advection, mixing, and residence time. The study shows that approximately one-third of the inorganic nitrogen entering the shelf is lost, with the most severe deficits observed in certain areas.
CONTINENTAL SHELF RESEARCH
(2021)
Article
Agronomy
Lei Cui, Dongpo Li, Zhijie Wu, Yan Xue, Furong Xiao, Lili Zhang, Yuchao Song, Yonghua Li, Ye Zheng, Jinming Zhang, Yongkun Cui
Summary: The application of nitrification inhibitors in combination can effectively reduce nitrate content and potential nitrification rate in soils with different pH values. The combination of nitrapyrin and dicyandiamide (CP+DCD) is the most effective in inhibiting soil nitrification and reducing NH3 volatilization in acidic soils. Further research is needed to evaluate the effects of these inhibitors in field conditions.
Article
Soil Science
Helen L. Hayden, Lori A. Phillips, Alexis J. Marshall, Jason R. Condon, Gregory S. Doran, Gregory S. Wells, Pauline M. Mele
Summary: The study found that nitrapyrin co-applied with urea ammonium nitrate can inhibit nitrification in soils by reducing nitrate accumulation and inhibiting the growth of ammonia oxidising bacteria. Additionally, the study discovered increased abundance of archaeal amoA gene in response to the co-application of nitrapyrin and UAN, possibly due to reduced competition from ammonia oxidising bacteria. Nevertheless, conclusive effects on downstream N transformations could not be discerned for the four soils.
APPLIED SOIL ECOLOGY
(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
Engineering, Civil
Yuandong Deng, Xueyan Ye, Xinqiang Du
Summary: Nitrate contamination of shallow groundwater in agricultural intensification regions is a global issue that affects food security, human health, and water ecology. Developing a prediction model to assess nitrate contamination is crucial for protecting groundwater resources. This study used hydrochemical data from Northeast China to group the dataset based on land use type, vadose zone type, and thickness. Machine learning models were then employed, and the advantages and disadvantages of different models were assessed. The results showed that the integration of the radial basis function artificial neural network (RBF ANN) model and principal components regression (PCR) model provided accurate predictions and improved interpretability. The study also identified the factors that impact nitrate concentrations in groundwater and highlighted the importance of both external and internal driving factors.
JOURNAL OF HYDROLOGY
(2023)
Article
Environmental Sciences
Shengnan Ke, Jiajun Chen, Xilai Zheng
Summary: This study established a model to study the migration and transformation of ammonium and nitrate in the unsaturated zone when ammonium fertilizer and nitrate coexist. The study introduced the proportional coefficient method and hypothetical assignment method to quantify the fate proportions of nitrate from different sources.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Horticulture
Bruno John Lewis Pitton, Ariesha Mayanka Wikramanayake, Grant Edward Johnson
Summary: Uniform incorporation of controlled-release fertilizer (CRF) is recommended to reduce nitrogen leaching in container-plant production. This study tested the potential damage to CRF prill coating when mechanically incorporated into a soilless substrate. Results showed that mechanically incorporated CRF resulted in greater leaching losses compared to manual incorporation, possibly due to prill coating damage. Researchers should report incorporation method and producers should ensure equipment does not damage CRF.
Article
Green & Sustainable Science & Technology
Rong Jiang, Jingyi Yang, Craig F. Drury, Brian B. Grant, Ward N. Smith, Wentian He, Daniel W. Reynolds, Ping He
Summary: The application of urease and nitrification inhibitors is an effective strategy for reducing nitrogen losses without impacting yields, but their long-term effects on nitrogen dynamics remain unclear.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Engineering, Environmental
Lei Li, Baogang Zhang, Jiaxin Shi, Jinxi He, Wei Zhang, Wenyue Yan, Min Li, Chongjian Tang, Hailong Li
Summary: This study demonstrates a novel strategy for the treatment of vanadium-bearing smelting wastewater using a membrane biofilm reactor to simultaneously remove vanadate and ammonium ions.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Green & Sustainable Science & Technology
Weifeng Deng, Litao Wang, Lang Cheng, Wenbo Yang, Dawen Gao
Summary: This paper reviewed the recent advances of anammox based processes for mature landfill leachate treatment and suggested some improvements to enhance the process efficiency.
Article
Environmental Sciences
Colette L. Kelly, Nicole M. Travis, Pascale A. Baya, Karen L. Casciotti
Summary: By analyzing N2O concentration and isotopologues in the eastern tropical North Pacific (ETNP), it was found that high N2O levels observed at some stations may be due to unique conditions supporting high rates of N2O production. Additionally, the study revealed different sources and potential mechanisms contributing to N2O cycling in oxygen deficient zones.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Limnology
Hannah L. Joy-Warren, Anne-Carlijn Alderkamp, Gert L. van Dijken, Loay Jabre, Erin M. Bertrand, Evan N. Baldonado, Molly W. Glickman, Kate M. Lewis, Rob Middag, Kyyas Seyitmuhammedov, Kate E. Lowry, Willem van de Poll, Kevin R. Arrigo
Summary: Light and iron availability are interconnected in controlling Southern Ocean primary production. Changes in light and iron can affect phytoplankton species composition and nutrient cycling. Light limits growth while iron does not, despite overall low iron concentrations.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Chemistry, Multidisciplinary
Kyyas Seyitmuhammedov, Claudine H. Stirling, Malcolm R. Reid, Robert van Hale, Patrick Laan, Kevin R. Arrigo, Gert van Dijken, Anne-Carlijn Alderkamp, Rob Middag
Summary: This study investigates the distribution of iron (Fe) in the Western Antarctic Peninsula (WAP) during early sea-ice retreat, finding increased Fe inputs from ice melt and sediments contributing to higher Fe concentrations in shelf waters. The research suggests that Fe from melting sea ice and shallow sedimentary sources can enhance phytoplankton productivity in WAP waters, especially in off-shelf regions with improved light conditions.
Review
Oceanography
Padmini Dalpadado, Kevin R. Arrigo, Gert L. van Dijken, Sudheera S. Gunasekara, Marek Ostrowski, Gabriella Bianchi, Erik Sperfeld
Summary: The Indian Ocean has experienced significant changes in sea temperature and warm pool area over the past 20 years, with a noticeable increase in the south-central basin. Sea surface temperature has generally risen while productivity has decreased in the northern and central regions, with an exception of increased productivity in the south-central basin. These trends over the last decade highlight a general increase in ocean temperature and decrease in productivity in the Indian Ocean, along with significant changes in warm pool area.
PROGRESS IN OCEANOGRAPHY
(2021)
Article
Environmental Sciences
Patrick J. Monreal, Colette L. Kelly, Nicole M. Travis, Karen L. Casciotti
Summary: This study analyzed the concentration and isotopocule ratios of N2O in the Eastern Tropical North Pacific (ETNP) to investigate the sources and controls of N2O cycling in this region. The results identified three distinct biogeochemical regimes and found that N2O production and consumption co-occur in oxygen-deficient zones. The study also linked N2O production mechanisms to a mesoscale eddy, highlighting the importance of eddies in spatiotemporal variability of N2O cycling and emissions.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Oceanography
Ouyang Zhangxian, Andrew Collins, Yun Li, Di Qi, Kevin R. Arrigo, Yanpei Zhuang, Shigeto Nishino, Matthew P. Humphreys, Naohiro Kosugi, Akihiko Murata, David L. Kirchman, Liqi Chen, Jianfang Chen, Wei-Jun Cai
Summary: The Chukchi Sea is becoming a larger sink for CO2 due to rapid climate changes. Understanding the seasonal variations in air-sea CO2 exchange and the biogeochemical dynamics is crucial for predicting the impacts of climate change on the ocean and the feedbacks. The study finds that thermal and non-thermal effects have different impacts on sea surface CO2 levels and air-sea CO2 flux in different water masses. The findings also highlight the importance of phytoplankton stoichiometry in CO2 uptake.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Limnology
Claudia Frey, Xin Sun, Laura Szemberski, Karen L. Casciotti, Emilio Garcia-Robledo, Amal Jayakumar, Colette L. Kelly, Moritz F. Lehmann, Bess B. Ward
Summary: Marine oxygen-deficient zones serve as a natural source of nitrous oxide (N2O), a powerful greenhouse gas and ozone-depleting agent. Through experiments conducted in the Eastern Tropical North Pacific, it was found that ammonia oxidation (AO) is controlled by oxygen (O-2) and ammonium (NH4+) concentrations, leading to N2O production. The study also showed that the yield of N2O from AO is solely influenced by O-2 concentration.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Limnology
Claudette Proctor, Pierre Coupel, Karen Casciotti, Jean-Eric Tremblay, Emily Zakem, Kevin R. Arrigo, Matthew M. Mills
Summary: This study found that light and sea ice concentration are important controls on nitrification in the Chukchi Sea, while high ammonium concentrations enhance nitrification. Unlike previous studies, nitrification rates were found to be higher under low pH conditions. These findings will guide future research on the implications of climate change on nitrogen biogeochemistry in the Chukchi Sea.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Oceanography
Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. van Dijken
Summary: The upward advection or mixing of iron-rich deep waters driven by the rate of basal ice shelf melt is a primary control on chlorophyll a production in coastal polynyas over the Antarctic continental shelf. This study examined the effects of projected atmospheric changes in 2100 on this relationship using a 5-km resolution ocean/sea ice/ice shelf model. The modified atmospheric conditions resulted in increased heat advection onto the continental shelf, increased basal ice shelf melt, and increased dissolved iron supply to the surface waters.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Chemistry, Multidisciplinary
Sian F. Henley, Stefano Cozzi, Francois Fripiat, Delphine Lannuzel, Daiki Nomura, David N. Thomas, Klaus M. Meinersg, Martin Vancoppenollej, Kevin Arrigo, Jacqueline Stefels, Maria van Leeuwe, Sebastien Moreau, Elizabeth M. Jones, Agneta Fransson, Melissa Chierici, Bruno Delilleo
Summary: This study presents a new compilation of macronutrient concentration data in Antarctic land-fast sea ice, covering the full seasonal cycle. The research reveals a strong seasonal cycle of nutrient concentrations, with high levels in autumn and winter and utilization by ice algal communities in spring and summer. It also suggests a degree of nutrient limitation in ice algal primary production, with silicon limitation being the most prevalent. Various factors, such as brine convection and under-ice tidal currents, influence nutrient supply to fast ice.
Article
Oceanography
Xue-Ji Gu, Lan Wang, Karen L. Casciotti, Yu Xin, Su-Mei Liu, Gui-Ling Zhang
Summary: This study presents the first analysis of N2O isotopes in the East China Sea and investigates N2O production processes in coastal water. The results show that both archaeal nitrification and/or hybrid mechanism and nitrifier denitrification contribute to N2O production. Additionally, far-field lateral advection serves as a potential physical supply of deeper N2O.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Environmental Sciences
Hannah L. Joy-Warren, Kate M. Lewis, Mathieu Ardyna, Jean-Eric Tremblay, Marcel Babin, Kevin R. Arrigo
Summary: As sea ice continues to decline rapidly in the Arctic, the adaptation of phytoplankton to different light conditions was investigated in this study. Three different light regimes – under the ice, in the marginal ice zone, and in open water – were examined during the Green Edge cruise in Baffin Bay in spring-summer 2016. The experiments conducted demonstrated that phytoplankton are well-prepared for a transition to high light conditions, even when originating from low light environments under sea ice.
ELEMENTA-SCIENCE OF THE ANTHROPOCENE
(2023)
Article
Environmental Sciences
Stephanie M. Lim, Courtney M. Payne, Gert L. van Dijken, Kevin R. Arrigo
Summary: Sea ice algae in the Arctic Ocean play a crucial role in primary production. Climate change-induced sea ice loss poses a threat to their persistence, but the replacement of multiyear ice with first-year ice might partially offset this threat and support ice algal growth.
ELEMENTA-SCIENCE OF THE ANTHROPOCENE
(2022)
Article
Environmental Sciences
Mathieu Ardyna, Douglas S. Hamilton, Tristan Harmel, Leo Lacour, Diana N. Bernstein, Julien Laliberte, Christopher Horvat, Remi Laxenaire, Matthew M. Mills, Gert van Dijken, Igor Polyakov, Herve Claustre, Natalie Mahowald, Kevin Robert Arrigo
Summary: The deposition of Siberian wildfire aerosols, containing nitrogen, enhanced phytoplankton growth in the eastern Eurasian Basin of the Arctic Ocean in summer 2014. This finding, supported by satellite-based ocean color data and atmospheric transport modeling, suggests that long range transport and deposition of wildfire aerosols can affect biogeochemical cycles in the Arctic Ocean.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Environmental Sciences
Tanya Marshall, Julie Granger, Karen L. Casciotti, Kirstin Dahnke, Kay-Christian Emeis, Dario Marconi, Matthew R. McIlvin, Abigail E. Noble, Mak A. Saito, Daniel M. Sigman, Sarah E. Fawcett
Summary: Biological dinitrogen fixation is crucial to the ocean's biological pump, but understanding its distribution and rate has been challenging due to uncertainty surrounding the controls. This study shows that the Angola Gyre in the eastern tropical South Atlantic is a hotspot for dinitrogen fixation, contradicting previous models. These findings suggest that the availability of iron and excess phosphorus from margin sediments play a key role in promoting dinitrogen fixation in this region.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)