Article
Environmental Sciences
Tanya Valkova, Vanessa Parravicini, Ernis Saracevic, Joseph Tauber, Karl Svardal, Jorg Krampe
Summary: N2O emissions in activated sludge tanks are mainly influenced by the activity of nitrifying bacteria and the efficiency of heterotrophic denitrification. Low-loaded plants achieving high nitrogen removal exhibit lower N2O emission intensity. The regression analysis shows a negative linear correlation between the N2O emission factor and the total nitrogen removal degree of the plants.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2021)
Article
Soil Science
Nadine Loick, Elizabeth Dixon, G. Peter Matthews, Christoph Mueller, Veronica S. Ciganda, Maria Lopez-Aizpun, Miguel A. Repullo, Laura M. Cardenas
Summary: This study quantifies the production and consumption pathways of N2O in soil using labelled substrate-N, showing the impact of different water filled pore space on N-transformation processes and emissions. The research highlights the importance of heterotrophic nitrification and denitrification in the N2O emissions, demonstrating the complex relationship between water filled pore space and nitrogen transformations.
Review
Engineering, Environmental
Nam-Hoon Lee, Sang-Hoon Song, Min-Jung Jung, Ran-Hui Kim, Jin-Kyu Park
Summary: This study outlines the dynamics of N2O in solid waste landfills and its emissions. N2O is mainly generated through denitrification and to a lesser extent, nitrification in anaerobic landfills. Landfill leachate treatment processes also contribute to significant N2O emissions. Bioreactor landfills emit more N2O than traditional anaerobic landfills due to various pathways such as NH2OH oxidation, nitrifier denitrification, and heterotrophic denitrification. Factors like C/N ratio, NH3 oxidation rate, redox conditions, and temperature affect these processes. Addressing N2O emissions from landfills is crucial for an integrated nitrogen management strategy.
ENVIRONMENTAL ENGINEERING RESEARCH
(2023)
Article
Agronomy
Qiurui Zhu, Eric A. Davidson, Jacob G. Hagedorn, Mark S. Castro, Thomas R. Fisher, Rebecca J. Fox, Shannon E. Brown, James W. Lewis
Summary: Drainage water management (DWM) is an effective practice to reduce nitrate export from croplands, but it may increase greenhouse gas emissions. This study evaluated the effects of DWM on greenhouse gas emissions and found no significant difference in emissions between DWM and non-DWM fields.
AGRICULTURAL AND FOREST METEOROLOGY
(2023)
Article
Multidisciplinary Sciences
Jianyu Yuan, Lijuan Yan, Guang Li, Mahran Sadiq, Nasir Rahim, Jiangqi Wu, Weiwei Ma, Guorong Xu, Mengyin Du
Summary: This study investigated the effects of conservation tillage techniques on soil N2O emission and yield in a semi-arid region of the Loess Plateau in Dingxi, China. The results showed that conservation tillage techniques improved soil physicochemical properties, increased organic carbon and nutrient content, and enhanced crop yield. Additionally, the impact of conservation tillage on soil N2O emission was relatively small, making it the recommended tillage strategy for the semi-arid environmental zone of the Loess Plateau.
SCIENTIFIC REPORTS
(2022)
Review
Environmental Sciences
Khushboo Gupta, Raushan Kumar, Kushal Kumar Baruah, Samarendra Hazarika, Susmita Karmakar, Nirmali Bordoloi
Summary: Agricultural soil, especially rice paddies, play a significant role in emitting greenhouse gases such as methane and nitrous oxide. Understanding the mechanisms and factors influencing the production and release of these gases is crucial in developing strategies to reduce emissions and mitigate global climate change impacts.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Article
Chemistry, Multidisciplinary
Pauline Sophie Rummel, Reinhard Well, Johanna Pausch, Birgit Pfeiffer, Klaus Dittert
Summary: Returning crop residues to agricultural fields can increase CO2 emissions and impact N2O and NO emissions, with different soil oxidation conditions promoting denitrification. The study found that maize litter can increase total CO2 emissions, but NO and N2O emissions were low under oxic conditions due to limited denitrification. Additionally, bacterial processes dominated N2O formation in the beginning, with a shift towards fungal denitrification later on.
APPLIED SCIENCES-BASEL
(2021)
Article
Agronomy
Ziyi Feng, Yongxiang Yu, Huaiying Yao, Chaorong Ge
Summary: This study found that the presence of ZnO nanoparticles can increase N2O emissions in soil, especially when coupled with C and N substrate amendments. The action of ZnO NPs promotes nitrification and denitrification processes, further impacting the functional genes associated with N2O emissions.
Article
Environmental Sciences
Xueji Gu, Fang Cheng, Xiaolei Chen, Guanxiang Du, Guiling Zhang
Summary: Coastal marine systems are active regions for the production and emission of nitrous oxide (N2O), with NH2OH being a potential precursor of N2O. However, the factors regulating coastal N2O cycling remain poorly understood. Our study in the South Yellow Sea (SYS) and the East China Sea (ECS) revealed high variability in N2O concentrations, with no clear relationship between N2O and NH2OH, suggesting NH2OH pathway may not be the only process influencing N2O production.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Vanessa Parravicini, Per Henrik Nielsen, Dines Thornberg, Alberto Pistocchi
Summary: We present an assessment of greenhouse gas emissions from urban wastewater treatment plants in Europe, and propose solutions to reduce these emissions. Our assessment considers various factors that contribute to emissions, such as infrastructure, sewer networks, treatment processes, and the composition of treated effluents.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Environmental Sciences
Daniel F. C. Dias, Ricardo Marques, Carla Martins, Antonio Martins, Adrian Oehmen
Summary: This study examined seasonal changes in N2O emissions at an activated sludge WWTP in a tourist region, finding higher N2O emissions in the low season despite lower loading rates, contradicting literature suggestions. Operational changes at WWTP were found to have a significant impact on N2O emissions, with aeration rate showing a strong correlation. The study suggests that the hydroxylamine oxidation pathway may play a more significant role in N2O production than nitrifier denitrification.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Yueyue Si, Yizhu Zhu, Ian Sanders, Dorothee B. Kinkel, Kevin J. Purdy, Mark Trimmer
Summary: This study found that freshwater communities are capable of fixing both N-2 and N2O, with different seasonalities and temperature dependencies. N2O fixation is less sensitive to temperature compared to N-2 fixation, resulting in a strong sink for N2O in colder months.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Johannes Friedl, Clemens Scheer, Daniele De Rosa, Christoph Mueller, Peter R. Grace, David W. Rowlings
Summary: The study highlights that rainfall and irrigation can lead to large pulses of N2O emissions from intensively managed pastures, emphasizing the need to determine the magnitude and sources of N2O under such conditions. Different pathways of N2O production respond differently to wetting, with denitrification being the main pathway even at low water-filled pore space levels. Heterotrophic nitrification plays a significant role in N2O emissions, especially as wetting increases.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Morten Lykkegaard Christensen, Anne Hojmark Jakobsen, Cecilie Sofie Kragelund Hansen, Mads Skovbjerg, Rikke Bruun Munk Andersen, Mette Dam Jensen, Kim Sundmark
Summary: This article describes a wastewater treatment plant designed to focus equally on energy production, water quality, and reduced emissions of greenhouse gases. The plant utilizes a disk filter to remove carbon during primary treatment, followed by hydrolysis and centrifugation to produce a hydrolysate centrate that can be used for secondary wastewater treatment or biogas production.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Meteorology & Atmospheric Sciences
Sambit Ghosh, Sakae Toyoda, Christo Buizert, David M. Etheridge, Ray L. Langenfelds, Naohiro Yoshida, Seong-Joong Kim, Jinho Ahn
Summary: To better understand the dynamics of N2O in the atmosphere, we reconstructed N2O values from ice cores, firn air archives, and modern atmospheric samples. Our findings show a three-phased growth of N2O, with a significant increase after 1965 CE. The decreasing trend in isotope values suggests an increasing contribution from anthropogenic sources. The continental region has been identified as the major hotspot of anthropogenic emissions.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geochemistry & Geophysics
Yuta Isaji, C. Yoshikawa, N. O. Ogawa, K. Matsumoto, A. Makabe, S. Toyoda, N. F. Ishikawa, H. Ogawa, H. Saito, M. C. Honda, N. Ohkouchi
Summary: In this study, nitrogen isotopic analysis of chlorophylls in the eastern Indian Ocean revealed differences in nitrogen source assimilation by phytoplankton species, with specific chlorophylls providing insights into isotopic variability within the community. The results highlighted subtle variations in nitrate availability at the subsurface chlorophyll maximum along a meridional transect.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Chemistry, Multidisciplinary
Kushi Kudo, Sakae Toyoda, Keita Yamada, Naohiro Yoshida, Daisuke Sasano, Naohiro Kosugi, Akihiko Murata, Hiroshi Uchida, Shigeto Nishino
Summary: Rapid sea-ice retreat in the Arctic Ocean can lead to the release of methane, with significant variations in concentration and isotopic ratios. Organic matter degradation in seafloor sediment is the main source of methane, and the production is influenced by strong winds and sea-ice melt water.
Article
Biochemical Research Methods
Joachim Mohn, Christina Biasi, Samuel Bode, Pascal Boeckx, Paul J. Brewer, Sarah Eggleston, Heike Geilmann, Myriam Guillevic, Jan Kaiser, Kristyna Kantnerova, Heiko Moossen, Joanna Muller, Mayuko Nakagawa, Ruth Pearce, Isabell von Rein, David Steger, Sakae Toyoda, Wolfgang Wanek, Sarah K. Wexler, Naohiro Yoshida, Longfei Yu
Summary: This study developed a set of seven N2O isotope Reference Materials (RMs) that will promote the implementation of the recommended two-point calibration approach and enhance compatibility between laboratories, making significant progress in N2O isotope research.
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
(2022)
Article
Geochemistry & Geophysics
Kristyna Kantnerova, Shohei Hattori, Sakae Toyoda, Naohiro Yoshida, Lukas Emmenegger, Stefano M. Bernasconi, Joachim Mohn
Summary: This study provides the first determination of enrichment factors of N2O clumped isotopes during bacterial denitrification, revealing different isotope effect in nitrate reduction process.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Microbiology
Alexis Gilbert, Mayuko Nakagawa, Koudai Taguchi, Naizhong Zhang, Akifumi Nishida, Naohiro Yoshida
Summary: Understanding hydrocarbon cycling in the subsurface is important in various disciplines. Mud volcanoes provide insights into biogeochemical processes. New hydrocarbon isotope analysis data from the Tokamachi mud volcano area in Japan suggests that C2+ hydrocarbons are being biodegraded with methane production.
Article
Engineering, Environmental
Syuichi Itahashi, Shohei Hattori, Akinori Ito, Yasuhiro Sadanaga, Naohiro Yoshida, Atsushi Matsuki
Summary: This study improves the modeling of SO42??? formation processes using the mass-independent oxygen isotopic composition [17O-excess; ??17O(SO42???)], and highlights the importance of dust and high metal solubility in the formation of SO42??? in the region downstream of China.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Daoping He, Hideshi Ooka, Yamei Li, Yujeong Kim, Akira Yamaguchi, Kiyohiro Adachi, Daisuke Hashizume, Naohiro Yoshida, Sakae Toyoda, Sun Hee Kim, Ryuhei Nakamura
Summary: This study reports the electrochemical regulation of a nitrite reduction network using a molybdenum sulfide catalyst by modulating the thermodynamic driving force of proton and electron transfer. The strategy is based on the theory of sequential proton-electron transfer and enables selective regulation of the desired reactions with high selectivity.
Article
Genetics & Heredity
Paula Prondzinsky, Sakae Toyoda, Shawn Erin McGlynn
Summary: Temperature is a crucial factor in biological processes, but there is still a lack of comprehensive understanding of temperature adaptation in biology. In this study, the genomes of psychrotolerant and thermotolerant methanogens were compared, which are physiologically related and can grow at temperatures ranging from -2.5°C to 122°C. Despite belonging to different phyla in the archaea, the core genome of cultivated methanogens accounts for about one-third of the total genome, and the shared genome fraction decreases with increasing phylogenetic distance. The increase in methanogenic growth temperature is associated with a reduction in genome size, and thermotolerant organisms, distributed across the archaeal tree, have larger core genome fractions, indicating that genome size is determined by temperature rather than phylogeny. Thermotolerant methanogens are enriched in metal and other transporters, while psychrotolerant methanogens are enriched in proteins related to structure and motility. Differences in amino acid composition between temperature groups include proteome charge, polarity, and unfolding entropy. This study suggests that shared physiology maintains a large, conserved genomic core in methanogens, even across large phylogenetic distances and extreme temperature conditions.
Article
Biochemical Research Methods
Koichiro Sumi, Kinuyo Munakata, Mayuko Nakagawa, Keita Yamada, Naohiro Yoshida
Summary: In this study, a novel method was developed to evaluate protein turnover using deuterium labeling of alanine and elemental analysis-coupled isotope ratio mass spectrometry (EA-IRMS). The rate of protein synthesis was calculated using the increase of deuterium excess over time, and the effect of insulin and rapamycin on protein turnover was analyzed.
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
(2023)
Article
Meteorology & Atmospheric Sciences
Sambit Ghosh, Sakae Toyoda, Christo Buizert, David M. Etheridge, Ray L. Langenfelds, Naohiro Yoshida, Seong-Joong Kim, Jinho Ahn
Summary: To better understand the dynamics of N2O in the atmosphere, we reconstructed N2O values from ice cores, firn air archives, and modern atmospheric samples. Our findings show a three-phased growth of N2O, with a significant increase after 1965 CE. The decreasing trend in isotope values suggests an increasing contribution from anthropogenic sources. The continental region has been identified as the major hotspot of anthropogenic emissions.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Environmental Sciences
Sakae Toyoda, Kotaro Terajima, Naohiro Yoshida, Chisato Yoshikawa, Akiko Makabe, Fuminori Hashihama, Hiroshi Ogawa
Summary: The production of nitrous oxide (N2O) by microorganisms in the Bay of Bengal (BoB) increases during the autumn intermonsoon, making it an important source of atmospheric N2O. Isotopic signatures suggest that bacterial denitrification and archeal nitrification play key roles in N2O production in the BoB. If the accumulated N2O is emitted into the atmosphere during the subsequent monsoon season, the BoB could be a significant N2O source similar to the Arabian Sea and eastern tropical Pacific.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Environmental Sciences
Kazuya Nishina, Lulie Melling, Sakae Toyoda, Masayuki Itoh, Kotaro Terajima, Joseph W. B. Waili, Guan X. Wong, Frankie Kiew, Edward B. Aeries, Ryuichi Hirata, Yoshiyuki Takahashi, Takashi Onodera
Summary: Oil palm plantations in peat-swamp areas in Sarawak, Malaysia, have a unique water management system that may lead to indirect emissions of N2O. Spatial monitoring showed that the drainage water in the palm oil plantations had over-saturated concentrations of dissolved N2O, suggesting that it may be a source of N2O emissions to the atmosphere. Isotopic analysis revealed that denitrification was the major source of N2O, followed by N2O reduction processes in the drainage water. A significant proportion of the N2O produced in the peat and drainage was reduced to N2 before being released into the atmosphere.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)