Articles | Volume 21, issue 14
https://doi.org/10.5194/bg-21-3215-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-21-3215-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
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17 Jul 2024
Research article | Highlight paper |
| 17 Jul 2024
| 17 Jul 2024
Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production
Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
Nicole M. Travis
Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
Pascale Anabelle Baya
Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
Claudia Frey
Department of Environmental Science, University of Basel, Basel, Switzerland
Department of Global Ecology, Carnegie Institution for Science, Stanford, CA 94305, USA
Bess B. Ward
Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
Karen L. Casciotti
Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
Oceans Department, Stanford University, Stanford, CA 94305, USA
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Nicole M. Travis, Colette L. Kelly, and Karen L. Casciotti
Biogeosciences, 21, 1985–2004, https://doi.org/10.5194/bg-21-1985-2024, https://doi.org/10.5194/bg-21-1985-2024, 2024
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We conducted experimental manipulations of light level on microbial communities from the primary nitrite maximum. Overall, while individual microbial processes have different directions and magnitudes in their response to increasing light, the net community response is a decline in nitrite production with increasing light. We conclude that while increased light may decrease net nitrite production, high-light conditions alone do not exclude nitrification from occurring in the surface ocean.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
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The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Jenna Alyson Lee, Joseph H. Vineis, Mathieu A. Poupon, Laure Resplandy, and Bess B. Ward
EGUsphere, https://doi.org/10.5194/egusphere-2025-871, https://doi.org/10.5194/egusphere-2025-871, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
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Concurrent sampling of environmental parameters, productivity rates, photopigments, and DNA were used to analyze a 24–L estuarine diatom bloom microcosm. Biogeochemical data and an ecological model indicated that the bloom was terminated by grazing. Comparisons to previous studies revealed (1) additional community and diversity complexity using 18S amplicon vs. traditional pigment–based analyses, and (2) a potential global productivity–diversity relationship using 18S and carbon transport rates.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
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Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Nicole M. Travis, Colette L. Kelly, and Karen L. Casciotti
Biogeosciences, 21, 1985–2004, https://doi.org/10.5194/bg-21-1985-2024, https://doi.org/10.5194/bg-21-1985-2024, 2024
Short summary
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We conducted experimental manipulations of light level on microbial communities from the primary nitrite maximum. Overall, while individual microbial processes have different directions and magnitudes in their response to increasing light, the net community response is a decline in nitrite production with increasing light. We conclude that while increased light may decrease net nitrite production, high-light conditions alone do not exclude nitrification from occurring in the surface ocean.
Weiyi Tang, Bess B. Ward, Michael Beman, Laura Bristow, Darren Clark, Sarah Fawcett, Claudia Frey, François Fripiat, Gerhard J. Herndl, Mhlangabezi Mdutyana, Fabien Paulot, Xuefeng Peng, Alyson E. Santoro, Takuhei Shiozaki, Eva Sintes, Charles Stock, Xin Sun, Xianhui S. Wan, Min N. Xu, and Yao Zhang
Earth Syst. Sci. Data, 15, 5039–5077, https://doi.org/10.5194/essd-15-5039-2023, https://doi.org/10.5194/essd-15-5039-2023, 2023
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Nitrification and nitrifiers play an important role in marine nitrogen and carbon cycles by converting ammonium to nitrite and nitrate. Nitrification could affect microbial community structure, marine productivity, and the production of nitrous oxide – a powerful greenhouse gas. We introduce the newly constructed database of nitrification and nitrifiers in the marine water column and guide future research efforts in field observations and model development of nitrification.
John C. Tracey, Andrew R. Babbin, Elizabeth Wallace, Xin Sun, Katherine L. DuRussel, Claudia Frey, Donald E. Martocello III, Tyler Tamasi, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 20, 2499–2523, https://doi.org/10.5194/bg-20-2499-2023, https://doi.org/10.5194/bg-20-2499-2023, 2023
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Nitrogen (N) is essential for life; thus, its availability plays a key role in determining marine productivity. Using incubations of seawater spiked with a rare form of N measurable on a mass spectrometer, we quantified microbial pathways that determine marine N availability. The results show that pathways that recycle N have higher rates than those that result in its loss from biomass and present new evidence for anaerobic nitrite oxidation, a process long thought to be strictly aerobic.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
Short summary
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The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Mhlangabezi Mdutyana, Tanya Marshall, Xin Sun, Jessica M. Burger, Sandy J. Thomalla, Bess B. Ward, and Sarah E. Fawcett
Biogeosciences, 19, 3425–3444, https://doi.org/10.5194/bg-19-3425-2022, https://doi.org/10.5194/bg-19-3425-2022, 2022
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Nitrite-oxidizing bacteria in the winter Southern Ocean show a high affinity for nitrite but require a minimum (i.e., "threshold") concentration before they increase their rates of nitrite oxidation significantly. The classic Michaelis–Menten model thus cannot be used to derive the kinetic parameters, so a modified equation was employed that also yields the threshold nitrite concentration. Dissolved iron availability may play an important role in limiting nitrite oxidation.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
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Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Amal Jayakumar and Bess B. Ward
Biogeosciences, 17, 5953–5966, https://doi.org/10.5194/bg-17-5953-2020, https://doi.org/10.5194/bg-17-5953-2020, 2020
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Diversity and community composition of nitrogen-fixing microbes in the three main oxygen minimum zones of the world ocean were investigated using nifH clone libraries. Representatives of three main clusters of nifH genes were detected. Sequences were most diverse in the surface waters. The most abundant OTUs were affiliated with Alpha- and Gammaproteobacteria. The sequences were biogeographically distinct and the dominance of a few OTUs was commonly observed in OMZs in this (and other) studies.
Samuel T. Wilson, Alia N. Al-Haj, Annie Bourbonnais, Claudia Frey, Robinson W. Fulweiler, John D. Kessler, Hannah K. Marchant, Jana Milucka, Nicholas E. Ray, Parvadha Suntharalingam, Brett F. Thornton, Robert C. Upstill-Goddard, Thomas S. Weber, Damian L. Arévalo-Martínez, Hermann W. Bange, Heather M. Benway, Daniele Bianchi, Alberto V. Borges, Bonnie X. Chang, Patrick M. Crill, Daniela A. del Valle, Laura Farías, Samantha B. Joye, Annette Kock, Jabrane Labidi, Cara C. Manning, John W. Pohlman, Gregor Rehder, Katy J. Sparrow, Philippe D. Tortell, Tina Treude, David L. Valentine, Bess B. Ward, Simon Yang, and Leonid N. Yurganov
Biogeosciences, 17, 5809–5828, https://doi.org/10.5194/bg-17-5809-2020, https://doi.org/10.5194/bg-17-5809-2020, 2020
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The oceans are a net source of the major greenhouse gases; however there has been little coordination of oceanic methane and nitrous oxide measurements. The scientific community has recently embarked on a series of capacity-building exercises to improve the interoperability of dissolved methane and nitrous oxide measurements. This paper derives from a workshop which discussed the challenges and opportunities for oceanic methane and nitrous oxide research in the near future.
Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, https://doi.org/10.5194/bg-17-2263-2020, 2020
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The production of N2O via nitrification and denitrification associated with low-O2 waters is a major source of oceanic N2O. We investigated the regulation and dynamics of these processes with respect to O2 and organic matter inputs. The transcription of the key nitrification gene amoA rapidly responded to changes in O2 and strongly correlated with N2O production rates. N2O production by denitrification was clearly stimulated by organic carbon, implying that its supply controls N2O production.
Adeline N. Y. Cojean, Jakob Zopfi, Alan Gerster, Claudia Frey, Fabio Lepori, and Moritz F. Lehmann
Biogeosciences, 16, 4705–4718, https://doi.org/10.5194/bg-16-4705-2019, https://doi.org/10.5194/bg-16-4705-2019, 2019
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Our results demonstrate the importance of oxygen in regulating the fate of nitrogen (N) in the sediments of Lake Lugano south basin, Switzerland. Hence, our study suggests that, by changing oxygen concentration in bottom waters, the seasonal water column turnover may significantly regulate the partitioning between N removal and N recycling in surface sediments, and it is likely that a similar pattern can be expected in a wide range of environments.
Taylor S. Martin, François Primeau, and Karen L. Casciotti
Biogeosciences, 16, 347–367, https://doi.org/10.5194/bg-16-347-2019, https://doi.org/10.5194/bg-16-347-2019, 2019
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Nitrite is a key intermediate in many nitrogen (N) cycling processes in the ocean, particularly in areas with low oxygen that are hotspots for N loss. We have created a 3-D global N cycle model with nitrite as a tracer. Stable isotopes of N are also included in the model and we are able to model the isotope fractionation associated with each N cycling process. Our model accurately represents N concentrations and isotope distributions in the ocean.
Qixing Ji, Claudia Frey, Xin Sun, Melanie Jackson, Yea-Shine Lee, Amal Jayakumar, Jeffrey C. Cornwell, and Bess B. Ward
Biogeosciences, 15, 6127–6138, https://doi.org/10.5194/bg-15-6127-2018, https://doi.org/10.5194/bg-15-6127-2018, 2018
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Nitrous oxide (N2O) is a strong greenhouse gas and ozone-depletion agent. Intense N2O effluxes had been observed from nutrient-rich estuaries with human impacts, such as the Chesapeake Bay. We report that increased nitrogen availability and low-oxygen conditions stimulate N2O production. Thus, controlling the nutrient input to the bay will decrease nitrogen availability and alleviate eutrophication, leading to water column reoxygenation, and subsequently will mitigate N2O emission.
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Biogeosciences, 22, 659–674, https://doi.org/10.5194/bg-22-659-2025, https://doi.org/10.5194/bg-22-659-2025, 2025
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Biogeosciences, 22, 555–584, https://doi.org/10.5194/bg-22-555-2025, https://doi.org/10.5194/bg-22-555-2025, 2025
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Tuula Aalto, Aki Tsuruta, Jarmo Mäkelä, Jurek Müller, Maria Tenkanen, Eleanor Burke, Sarah Chadburn, Yao Gao, Vilma Mannisenaho, Thomas Kleinen, Hanna Lee, Antti Leppänen, Tiina Markkanen, Stefano Materia, Paul A. Miller, Daniele Peano, Olli Peltola, Benjamin Poulter, Maarit Raivonen, Marielle Saunois, David Wårlind, and Sönke Zaehle
Biogeosciences, 22, 323–340, https://doi.org/10.5194/bg-22-323-2025, https://doi.org/10.5194/bg-22-323-2025, 2025
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Biogeosciences, 22, 305–321, https://doi.org/10.5194/bg-22-305-2025, https://doi.org/10.5194/bg-22-305-2025, 2025
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This study assesses global methane emissions from wetlands between 2000 and 2020 using multiple models. We found that wetland emissions increased by 6–7 Tg CH4 yr-1 in the 2010s compared to the 2000s. Rising temperatures primarily drove this increase, while changes in precipitation and CO2 levels also played roles. Our findings highlight the importance of wetlands in the global methane budget and the need for continuous monitoring to understand their impact on climate change.
Lorena Carrasco-Barea, Dolors Verdaguer, Maria Gispert, Xavier D. Quintana, Hélène Bourhis, and Laura Llorens
Biogeosciences, 22, 289–304, https://doi.org/10.5194/bg-22-289-2025, https://doi.org/10.5194/bg-22-289-2025, 2025
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Carbon dioxide fluxes have been measured seasonally in four plant species in a Mediterranean non-tidal salt marsh, highlighting the high carbon removal potential that these species have. Carbon dioxide and methane emissions from soil showed high variability among the habitats studied, and they were generally higher than those observed in tidal salt marshes. Our results are important for making more accurate predictions regarding carbon emissions from these ecosystems.
Ekaterina Ezhova, Topi Laanti, Anna Lintunen, Pasi Kolari, Tuomo Nieminen, Ivan Mammarella, Keijo Heljanko, and Markku Kulmala
Biogeosciences, 22, 257–288, https://doi.org/10.5194/bg-22-257-2025, https://doi.org/10.5194/bg-22-257-2025, 2025
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Machine learning (ML) models are gaining popularity in biogeosciences. They are applied as gap-filling methods and used to upscale carbon fluxes to larger areas. Here we use explainable artificial intelligence (XAI) methods to elucidate the performance of machine learning models for carbon dioxide fluxes in boreal forests. We show that statistically equal models treat input variables differently. XAI methods can help scientists make informed decisions when applying ML models in their research.
Jessica Breavington, Alexandra Steckbauer, Chuancheng Fu, Mongi Ennasri, and Carlos M. Duarte
Biogeosciences, 22, 117–134, https://doi.org/10.5194/bg-22-117-2025, https://doi.org/10.5194/bg-22-117-2025, 2025
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Mangrove carbon storage in the Red Sea is lower than average due to challenging growth conditions. We collected mangrove soil cores over multiple seasons to measure greenhouse gas (GHG) flux of carbon dioxide and methane. GHG emissions are a small offset to mangrove carbon storage overall but punctuated by periods of high emission. This variation is linked to environmental and soil properties, which were also measured. The findings aid understanding of GHG dynamics in arid mangrove ecosystems.
Johnathan Daniel Maxey, Neil D. Hartstein, Hermann W. Bange, and Moritz Müller
Biogeosciences, 21, 5613–5637, https://doi.org/10.5194/bg-21-5613-2024, https://doi.org/10.5194/bg-21-5613-2024, 2024
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The distribution of N2O in fjord-like estuaries is poorly described in the Southern Hemisphere. Our study describes N2O distribution and its drivers in one such system in Macquarie Harbour, Tasmania. Water samples were collected seasonally in 2022 and 2023. Results show the system removes atmospheric N2O when river flow is high, whereas the system emits N2O when the river flow is low. N2O generated in basins is intercepted by the surface water and exported to the ocean during high river flow.
Wael Al Hamwi, Maren Dubbert, Jörg Schaller, Matthias Lück, Marten Schmidt, and Mathias Hoffmann
Biogeosciences, 21, 5639–5651, https://doi.org/10.5194/bg-21-5639-2024, https://doi.org/10.5194/bg-21-5639-2024, 2024
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We present a fully automatic, low-cost soil–plant enclosure system to monitor CO2 and evapotranspiration fluxes within greenhouse experiments. It operates in two modes: independent, using low-cost sensors, and dependent, where multiple chambers connect to a single gas analyzer via a low-cost multiplexer. This system provides precise, accurate measurements and high temporal resolution, enabling comprehensive monitoring of plant–soil responses to various treatments and conditions.
Zhao-Jun Yong, Wei-Jen Lin, Chiao-Wen Lin, and Hsing-Juh Lin
Biogeosciences, 21, 5247–5260, https://doi.org/10.5194/bg-21-5247-2024, https://doi.org/10.5194/bg-21-5247-2024, 2024
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We measured CO2 and CH4 fluxes from mangrove stems and soils of Avicennia marina and Kandelia obovata during tidal cycles. Both stem types served as CO2 and CH4 sources, emitting less CH4 than soils, with no difference in CO2 flux. While A. marina stems showed increased CO2 fluxes from low to high tides, they acted as a CH4 sink before flooding and as a source after ebbing. However, K. obovata stems showed no flux pattern. This study highlights the need to consider tidal influence and species.
Ihab Alfadhel, Ignacio Peralta-Maraver, Isabel Reche, Enrique P. Sánchez-Cañete, Sergio Aranda-Barranco, Eva Rodríguez-Velasco, Andrew S. Kowalski, and Penélope Serrano-Ortiz
Biogeosciences, 21, 5117–5129, https://doi.org/10.5194/bg-21-5117-2024, https://doi.org/10.5194/bg-21-5117-2024, 2024
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Inland saline lakes are crucial in the global carbon cycle, but increased droughts may alter their carbon exchange capacity. We measured CO2 and CH4 fluxes in a Mediterranean saline lake using the eddy covariance method under dry and wet conditions. We found the lake acts as a carbon sink during wet periods but not during droughts. These results highlight the importance of saline lakes in carbon sequestration and their vulnerability to climate-change-induced droughts.
Nathaniel B. Weston, Cynthia Troy, Patrick J. Kearns, Jennifer L. Bowen, William Porubsky, Christelle Hyacinthe, Christof Meile, Philippe Van Cappellen, and Samantha B. Joye
Biogeosciences, 21, 4837–4851, https://doi.org/10.5194/bg-21-4837-2024, https://doi.org/10.5194/bg-21-4837-2024, 2024
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Nitrous oxide (N2O) is a potent greenhouse and ozone-depleting gas produced largely from microbial nitrogen cycling processes, and human activities have resulted in increases in atmospheric N2O. We investigate the role of physical and chemical disturbances to soils and sediments in N2O production. We demonstrate that physicochemical perturbation increases N2O production, microbial community adapts over time, and initial perturbation appears to confer resilience to subsequent disturbance.
Sigrid Trier Kjær, Sebastian Westermann, Nora Nedkvitne, and Peter Dörsch
Biogeosciences, 21, 4723–4737, https://doi.org/10.5194/bg-21-4723-2024, https://doi.org/10.5194/bg-21-4723-2024, 2024
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Permafrost peatlands are thawing due to climate change, releasing large quantities of carbon that degrades upon thawing and is released as CO2, CH4 or dissolved organic carbon (DOC). We incubated thawed Norwegian permafrost peat plateaus and thermokarst pond sediment found next to permafrost for up to 350 d to measure carbon loss. CO2 production was initially the highest, whereas CH4 production increased over time. The largest carbon loss was measured at the top of the peat plateau core as DOC.
Silvie Lainela, Erik Jacobs, Stella-Theresa Luik, Gregor Rehder, and Urmas Lips
Biogeosciences, 21, 4495–4519, https://doi.org/10.5194/bg-21-4495-2024, https://doi.org/10.5194/bg-21-4495-2024, 2024
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We evaluate the variability of carbon dioxide and methane in the surface layer of the north-eastern basins of the Baltic Sea in 2018. We show that the shallower coastal areas have considerably higher spatial variability and seasonal amplitude of surface layer pCO2 and cCH4 than measured in the offshore areas of the Baltic Sea. Despite this high variability, caused mostly by coastal physical processes, the average annual air–sea CO2 fluxes differed only marginally between the sub-basins.
Martti Honkanen, Mika Aurela, Juha Hatakka, Lumi Haraguchi, Sami Kielosto, Timo Mäkelä, Jukka Seppälä, Simo-Matti Siiriä, Ken Stenbäck, Juha-Pekka Tuovinen, Pasi Ylöstalo, and Lauri Laakso
Biogeosciences, 21, 4341–4359, https://doi.org/10.5194/bg-21-4341-2024, https://doi.org/10.5194/bg-21-4341-2024, 2024
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The exchange of CO2 between the sea and the atmosphere was studied in the Archipelago Sea, Baltic Sea, in 2017–2021, using an eddy covariance technique. The sea acted as a net source of CO2 with an average yearly emission of 27.1 gC m-2 yr-1, indicating that the marine ecosystem respired carbon that originated elsewhere. The yearly CO2 emission varied between 18.2–39.2 gC m-2 yr-1, mostly due to the yearly variation of ecosystem carbon uptake.
Ralf C. H. Aben, Daniël van de Craats, Jim Boonman, Stijn H. Peeters, Bart Vriend, Coline C. F. Boonman, Ype van der Velde, Gilles Erkens, and Merit van den Berg
Biogeosciences, 21, 4099–4118, https://doi.org/10.5194/bg-21-4099-2024, https://doi.org/10.5194/bg-21-4099-2024, 2024
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Drained peatlands cause high CO2 emissions. We assessed the effectiveness of subsurface water infiltration systems (WISs) in reducing CO2 emissions related to increases in water table depth (WTD) on 12 sites for up to 4 years. Results show WISs markedly reduced emissions by 2.1 t CO2-C ha-1 yr-1. The relationship between the amount of carbon above the WTD and CO2 emission was stronger than the relationship between WTD and emission. Long-term monitoring is crucial for accurate emission estimates.
Ingeborg Bussmann, Eric P. Achterberg, Holger Brix, Nicolas Brüggemann, Götz Flöser, Claudia Schütze, and Philipp Fischer
Biogeosciences, 21, 3819–3838, https://doi.org/10.5194/bg-21-3819-2024, https://doi.org/10.5194/bg-21-3819-2024, 2024
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Methane (CH4) is an important greenhouse gas and contributes to climate warming. However, the input of CH4 from coastal areas to the atmosphere is not well defined. Dissolved and atmospheric CH4 was determined at high spatial resolution in or above the North Sea. The atmospheric CH4 concentration was mainly influenced by wind direction. With our detailed study on the spatial distribution of CH4 fluxes we were able to provide a detailed and more realistic estimation of coastal CH4 fluxes.
Niu Zhu, Jinniu Wang, Dongliang Luo, Xufeng Wang, Cheng Shen, and Ning Wu
Biogeosciences, 21, 3509–3522, https://doi.org/10.5194/bg-21-3509-2024, https://doi.org/10.5194/bg-21-3509-2024, 2024
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Our study delves into the vital role of subalpine forests in the Qinghai–Tibet Plateau as carbon sinks in the context of climate change. Utilizing advanced eddy covariance systems, we uncover their significant carbon sequestration potential, observing distinct seasonal patterns influenced by temperature, humidity, and radiation. Notably, these forests exhibit robust carbon absorption, with potential implications for global carbon balance.
Hella van Asperen, Thorsten Warneke, Alessandro Carioca de Araújo, Bruce Forsberg, Sávio José Filgueiras Ferreira, Thomas Röckmann, Carina van der Veen, Sipko Bulthuis, Leonardo Ramos de Oliveira, Thiago de Lima Xavier, Jailson da Mata, Marta de Oliveira Sá, Paulo Ricardo Teixeira, Julie Andrews de França e Silva, Susan Trumbore, and Justus Notholt
Biogeosciences, 21, 3183–3199, https://doi.org/10.5194/bg-21-3183-2024, https://doi.org/10.5194/bg-21-3183-2024, 2024
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Carbon monoxide (CO) is regarded as an important indirect greenhouse gas. Soils can emit and take up CO, but, until now, uncertainty remains as to which process dominates in tropical rainforests. We present the first soil CO flux measurements from a tropical rainforest. Based on our observations, we report that tropical rainforest soils are a net source of CO. In addition, we show that valley streams and inundated areas are likely additional hot spots of CO in the ecosystem.
Yélognissè Agbohessou, Claire Delon, Manuela Grippa, Eric Mougin, Daouda Ngom, Espoir Koudjo Gaglo, Ousmane Ndiaye, Paulo Salgado, and Olivier Roupsard
Biogeosciences, 21, 2811–2837, https://doi.org/10.5194/bg-21-2811-2024, https://doi.org/10.5194/bg-21-2811-2024, 2024
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Emissions of greenhouse gases in the Sahel are not well represented because they are considered weak compared to the rest of the world. However, natural areas in the Sahel emit carbon dioxide and nitrous oxides, which need to be assessed because of extended surfaces. We propose an assessment of such emissions in Sahelian silvopastoral systems and of how they are influenced by environmental characteristics. These results are essential to inform climate change strategies in the region.
Merit van den Berg, Thomas M. Gremmen, Renske J. E. Vroom, Jacobus van Huissteden, Jim Boonman, Corine J. A. van Huissteden, Ype van der Velde, Alfons J. P. Smolders, and Bas P. van de Riet
Biogeosciences, 21, 2669–2690, https://doi.org/10.5194/bg-21-2669-2024, https://doi.org/10.5194/bg-21-2669-2024, 2024
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Drained peatlands emit 3 % of the global greenhouse gas emissions. Paludiculture is a way to reduce CO2 emissions while at the same time generating an income for landowners. The side effect is the potentially high methane emissions. We found very high methane emissions for broadleaf cattail compared with narrowleaf cattail and water fern. The rewetting was, however, effective to stop CO2 emissions for all species. The highest potential to reduce greenhouse gas emissions had narrowleaf cattail.
Antonio Donateo, Daniela Famulari, Donato Giovannelli, Arturo Mariani, Mauro Mazzola, Stefano Decesari, and Gianluca Pappaccogli
EGUsphere, https://doi.org/10.5194/egusphere-2024-1440, https://doi.org/10.5194/egusphere-2024-1440, 2024
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This study focuses on direct measurements of CO2 and CH4 turbulent eddy covariance fluxes in tundra ecosystems in the Svalbard Islands over a two-year period. Our results reveal dynamic interactions between climatic conditions and ecosystem activities such as photosynthesis and microbial activity. The observed net summertime methane uptake is correlated with the activation and aeration of soil microorganisms. High temperature anomalies increase CO2 and CH4 emissions.
Thea H. Heimdal, Galen A. McKinley, Adrienne J. Sutton, Amanda R. Fay, and Lucas Gloege
Biogeosciences, 21, 2159–2176, https://doi.org/10.5194/bg-21-2159-2024, https://doi.org/10.5194/bg-21-2159-2024, 2024
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Measurements of ocean carbon are limited in time and space. Machine learning algorithms are therefore used to reconstruct ocean carbon where observations do not exist. Improving these reconstructions is important in order to accurately estimate how much carbon the ocean absorbs from the atmosphere. In this study, we find that a small addition of observations from the Southern Ocean, obtained by autonomous sampling platforms, could significantly improve the reconstructions.
Guilherme L. Torres Mendonça, Julia Pongratz, and Christian H. Reick
Biogeosciences, 21, 1923–1960, https://doi.org/10.5194/bg-21-1923-2024, https://doi.org/10.5194/bg-21-1923-2024, 2024
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We study the timescale dependence of airborne fraction and underlying feedbacks by a theory of the climate–carbon system. Using simulations we show the predictive power of this theory and find that (1) this fraction generally decreases for increasing timescales and (2) at all timescales the total feedback is negative and the model spread in a single feedback causes the spread in the airborne fraction. Our study indicates that those are properties of the system, independently of the scenario.
François Clayer, Jan Erik Thrane, Kuria Ndungu, Andrew King, Peter Dörsch, and Thomas Rohrlack
Biogeosciences, 21, 1903–1921, https://doi.org/10.5194/bg-21-1903-2024, https://doi.org/10.5194/bg-21-1903-2024, 2024
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Determination of dissolved greenhouse gas (GHG) in freshwater allows us to estimate GHG fluxes. Mercuric chloride (HgCl2) is used to preserve water samples prior to GHG analysis despite its environmental and health impacts and interferences with water chemistry in freshwater. Here, we tested the effects of HgCl2, two substitutes and storage time on GHG in water from two boreal lakes. Preservation with HgCl2 caused overestimation of CO2 concentration with consequences for GHG flux estimation.
Helena Rautakoski, Mika Korkiakoski, Jarmo Mäkelä, Markku Koskinen, Kari Minkkinen, Mika Aurela, Paavo Ojanen, and Annalea Lohila
Biogeosciences, 21, 1867–1886, https://doi.org/10.5194/bg-21-1867-2024, https://doi.org/10.5194/bg-21-1867-2024, 2024
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Current and future nitrous oxide (N2O) emissions are difficult to estimate due to their high variability in space and time. Several years of N2O fluxes from drained boreal peatland forest indicate high importance of summer precipitation, winter temperature, and snow conditions in controlling annual N2O emissions. The results indicate increasing year-to-year variation in N2O emissions in changing climate with more extreme seasonal weather conditions.
Matthias Koschorreck, Norbert Kamjunke, Uta Koedel, Michael Rode, Claudia Schuetze, and Ingeborg Bussmann
Biogeosciences, 21, 1613–1628, https://doi.org/10.5194/bg-21-1613-2024, https://doi.org/10.5194/bg-21-1613-2024, 2024
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We measured the emission of carbon dioxide (CO2) and methane (CH4) from different sites at the river Elbe in Germany over 3 days to find out what is more important for quantification: small-scale spatial variability or diurnal temporal variability. We found that CO2 emissions were very different between day and night, while CH4 emissions were more different between sites. Dried out river sediments contributed to CO2 emissions, while the side areas of the river were important CH4 sources.
Odysseas Sifounakis, Edwin Haas, Klaus Butterbach-Bahl, and Maria P. Papadopoulou
Biogeosciences, 21, 1563–1581, https://doi.org/10.5194/bg-21-1563-2024, https://doi.org/10.5194/bg-21-1563-2024, 2024
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We performed a full assessment of the carbon and nitrogen cycles of a cropland ecosystem. An uncertainty analysis and quantification of all carbon and nitrogen fluxes were deployed. The inventory simulations include greenhouse gas emissions of N2O, NH3 volatilization and NO3 leaching from arable land cultivation in Greece. The inventory also reports changes in soil organic carbon and nitrogen stocks in arable soils.
Sarah M. Ludwig, Luke Schiferl, Jacqueline Hung, Susan M. Natali, and Roisin Commane
Biogeosciences, 21, 1301–1321, https://doi.org/10.5194/bg-21-1301-2024, https://doi.org/10.5194/bg-21-1301-2024, 2024
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Landscapes are often assumed to be homogeneous when using eddy covariance fluxes, which can lead to biases when calculating carbon budgets. In this study we report eddy covariance carbon fluxes from heterogeneous tundra. We used the footprints of each flux observation to unmix the fluxes coming from components of the landscape. We identified and quantified hot spots of carbon emissions in the landscape. Accurately scaling with landscape heterogeneity yielded half as much regional carbon uptake.
Justine Trémeau, Beñat Olascoaga, Leif Backman, Esko Karvinen, Henriikka Vekuri, and Liisa Kulmala
Biogeosciences, 21, 949–972, https://doi.org/10.5194/bg-21-949-2024, https://doi.org/10.5194/bg-21-949-2024, 2024
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We studied urban lawns and meadows in the Helsinki metropolitan area, Finland. We found that meadows are more resistant to drought events but that they do not increase carbon sequestration compared with lawns. Moreover, the transformation from lawns to meadows did not demonstrate any negative climate effects in terms of greenhouse gas emissions. Even though social and economic aspects also steer urban development, these results can guide planning to consider carbon-smart options.
Guantao Chen, Edzo Veldkamp, Muhammad Damris, Bambang Irawan, Aiyen Tjoa, and Marife D. Corre
Biogeosciences, 21, 513–529, https://doi.org/10.5194/bg-21-513-2024, https://doi.org/10.5194/bg-21-513-2024, 2024
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We established an oil palm management experiment in a large-scale oil palm plantation in Jambi, Indonesia. We recorded oil palm fruit yield and measured soil CO2, N2O, and CH4 fluxes. After 4 years of treatment, compared with conventional fertilization with herbicide weeding, reduced fertilization with mechanical weeding did not reduce yield and soil greenhouse gas emissions, which highlights the legacy effects of over a decade of conventional management prior to the start of the experiment.
Elizabeth Gachibu Wangari, Ricky Mwangada Mwanake, Tobias Houska, David Kraus, Gretchen Maria Gettel, Ralf Kiese, Lutz Breuer, and Klaus Butterbach-Bahl
Biogeosciences, 20, 5029–5067, https://doi.org/10.5194/bg-20-5029-2023, https://doi.org/10.5194/bg-20-5029-2023, 2023
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Agricultural landscapes act as sinks or sources of the greenhouse gases (GHGs) CO2, CH4, or N2O. Various physicochemical and biological processes control the fluxes of these GHGs between ecosystems and the atmosphere. Therefore, fluxes depend on environmental conditions such as soil moisture, soil temperature, or soil parameters, which result in large spatial and temporal variations of GHG fluxes. Here, we describe an example of how this variation may be studied and analyzed.
Laurie C. Menviel, Paul Spence, Andrew E. Kiss, Matthew A. Chamberlain, Hakase Hayashida, Matthew H. England, and Darryn Waugh
Biogeosciences, 20, 4413–4431, https://doi.org/10.5194/bg-20-4413-2023, https://doi.org/10.5194/bg-20-4413-2023, 2023
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As the ocean absorbs 25% of the anthropogenic emissions of carbon, it is important to understand the impact of climate change on the flux of carbon between the ocean and the atmosphere. Here, we use a very high-resolution ocean, sea-ice, carbon cycle model to show that the capability of the Southern Ocean to uptake CO2 has decreased over the last 40 years due to a strengthening and poleward shift of the southern hemispheric westerlies. This trend is expected to continue over the coming century.
Petr Znachor, Jiří Nedoma, Vojtech Kolar, and Anna Matoušů
Biogeosciences, 20, 4273–4288, https://doi.org/10.5194/bg-20-4273-2023, https://doi.org/10.5194/bg-20-4273-2023, 2023
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We conducted intensive spatial sampling of the hypertrophic fishpond to better understand the spatial dynamics of methane fluxes and environmental heterogeneity in fishponds. The diffusive fluxes of methane accounted for only a minor fraction of the total fluxes and both varied pronouncedly within the pond and over the studied summer season. This could be explained only by the water depth. Wind substantially affected temperature, oxygen and chlorophyll a distribution in the pond.
Sofie Sjögersten, Martha Ledger, Matthias Siewert, Betsabé de la Barreda-Bautista, Andrew Sowter, David Gee, Giles Foody, and Doreen S. Boyd
Biogeosciences, 20, 4221–4239, https://doi.org/10.5194/bg-20-4221-2023, https://doi.org/10.5194/bg-20-4221-2023, 2023
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Permafrost thaw in Arctic regions is increasing methane emissions, but quantification is difficult given the large and remote areas impacted. We show that UAV data together with satellite data can be used to extrapolate emissions across the wider landscape as well as detect areas at risk of higher emissions. A transition of currently degrading areas to fen type vegetation can increase emission by several orders of magnitude, highlighting the importance of quantifying areas at risk.
Cole G. Brachmann, Tage Vowles, Riikka Rinnan, Mats P. Björkman, Anna Ekberg, and Robert G. Björk
Biogeosciences, 20, 4069–4086, https://doi.org/10.5194/bg-20-4069-2023, https://doi.org/10.5194/bg-20-4069-2023, 2023
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Herbivores change plant communities through grazing, altering the amount of CO2 and plant-specific chemicals (termed VOCs) emitted. We tested this effect by excluding herbivores and studying the CO2 and VOC emissions. Herbivores reduced CO2 emissions from a meadow community and altered VOC composition; however, community type had the strongest effect on the amount of CO2 and VOCs released. Herbivores can mediate greenhouse gas emissions, but the effect is marginal and community dependent.
Ole Lessmann, Jorge Encinas Fernández, Karla Martínez-Cruz, and Frank Peeters
Biogeosciences, 20, 4057–4068, https://doi.org/10.5194/bg-20-4057-2023, https://doi.org/10.5194/bg-20-4057-2023, 2023
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Based on a large dataset of seasonally resolved methane (CH4) pore water concentrations in a reservoir's sediment, we assess the significance of CH4 emissions due to reservoir flushing. In the studied reservoir, CH4 emissions caused by one flushing operation can represent 7 %–14 % of the annual CH4 emissions and depend on the timing of the flushing operation. In reservoirs with high sediment loadings, regular flushing may substantially contribute to the overall CH4 emissions.
Matti Räsänen, Risto Vesala, Petri Rönnholm, Laura Arppe, Petra Manninen, Markus Jylhä, Jouko Rikkinen, Petri Pellikka, and Janne Rinne
Biogeosciences, 20, 4029–4042, https://doi.org/10.5194/bg-20-4029-2023, https://doi.org/10.5194/bg-20-4029-2023, 2023
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Fungus-growing termites recycle large parts of dead plant material in African savannas and are significant sources of greenhouse gases. We measured CO2 and CH4 fluxes from their mounds and surrounding soils in open and closed habitats. The fluxes scale with mound volume. The results show that emissions from mounds of fungus-growing termites are more stable than those from other termites. The soil fluxes around the mound are affected by the termite colonies at up to 2 m distance from the mound.
Tim René de Groot, Anne Margriet Mol, Katherine Mesdag, Pierre Ramond, Rachel Ndhlovu, Julia Catherine Engelmann, Thomas Röckmann, and Helge Niemann
Biogeosciences, 20, 3857–3872, https://doi.org/10.5194/bg-20-3857-2023, https://doi.org/10.5194/bg-20-3857-2023, 2023
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This study investigates methane dynamics in the Wadden Sea. Our measurements revealed distinct variations triggered by seasonality and tidal forcing. The methane budget was higher in warmer seasons but surprisingly high in colder seasons. Methane dynamics were amplified during low tides, flushing the majority of methane into the North Sea or releasing it to the atmosphere. Methanotrophic activity was also elevated during low tide but mitigated only a small fraction of the methane efflux.
Frederic Thalasso, Brenda Riquelme, Andrés Gómez, Roy Mackenzie, Francisco Javier Aguirre, Jorge Hoyos-Santillan, Ricardo Rozzi, and Armando Sepulveda-Jauregui
Biogeosciences, 20, 3737–3749, https://doi.org/10.5194/bg-20-3737-2023, https://doi.org/10.5194/bg-20-3737-2023, 2023
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A robust skirt-chamber design to capture and quantify greenhouse gas emissions from peatlands is presented. Compared to standard methods, this design improves the spatial resolution of field studies in remote locations while minimizing intrusion.
Cited articles
Babbin, A. R., Bianchi, D., Jayakumar, A., and Ward, B. B.: Rapid nitrous oxide cycling in the suboxic ocean, Science, 348, 1127–1129, https://doi.org/10.1126/science.aaa8380, 2015.
Bianchi, D., Weber, T. S., Kiko, R., and Deutsch, C.: Global niche of marine anaerobic metabolisms expanded by particle microenvironments, Nat. Geosci., 11, 263–268, https://doi.org/10.1038/s41561-018-0081-0, 2018.
Bianchi, D., McCoy, D., and Yang, S.: Formulation, optimization, and sensitivity of NitrOMZv1.0, a biogeochemical model of the nitrogen cycle in oceanic oxygen minimum zones, Geosci. Model Dev., 16, 3581–3609, https://doi.org/10.5194/gmd-16-3581-2023, 2023.
Böhlke, J. K., Mroczkowski, S. J., and Coplen, T. B.: Oxygen isotopes in nitrate: new reference materials for 18O : 17O : 16O measurements and observations on nitrate-water equilibration, Rapid Commun. Mass Sp., 17, 1835–1846, https://doi.org/10.1002/rcm.1123, 2003.
Bourbonnais, A., Letscher, R. T., Bange, H. W., Échevin, V., Larkum, J., Mohn, J., Yoshida, N., and Altabet, M. A.: N2O production and consumption from stable isotopic and concentration data in the Peruvian coastal upwelling system, Global Biogeochem. Cy., 31, 678–698, https://doi.org/10.1002/2016GB005567, 2017.
Bourbonnais, A., Chang, B. X., Sonnerup, R. E., Doney, S. C., and Altabet, M. A.: Marine N2O cycling from high spatial resolution concentration, stable isotopic and isotopomer measurements along a meridional transect in the eastern Pacific Ocean, Front. Mar. Sci., 10, 1137064, https://doi.org/10.3389/fmars.2023.1137064, 2023.
Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P., Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K., Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W. A., Pitcher, G. C., Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M., Yasuhara, M., and Zhang, J.: Declining oxygen in the global ocean and coastal waters, Science, 359, eaam7240, https://doi.org/10.1126/science.aam7240, 2018.
Brenninkmeijer, C. A. M. and Röckmann, T.: Mass spectrometry of the intramolecular nitrogen isotope distribution of environmental nitrous oxide using fragment-ion analysis, Rapid Commun. Mass Sp., 13, 2028–2033, https://doi.org/10.1002/(SICI)1097-0231(19991030)13:20<2028::AID-RCM751>3.0.CO;2-J, 1999.
Buchwald, C., Santoro, A. E., Stanley, R. H. R., and Casciotti, K. L.: Nitrogen cycling in the secondary nitrite maximum of the eastern tropical North Pacific off Costa Rica, Gloal Biogeochem. Cy., 29, 2061–2081, https://doi.org/10.1002/2015GB005187, 2015.
Busecke, J. J. M., Resplandy, L., Ditkovsky, S. J., and John, J. G.: Diverging Fates of the Pacific Ocean Oxygen Minimum Zone and Its Core in a Warming World, AGU Adv., 3, e2021AV000470, https://doi.org/10.1029/2021AV000470, 2022.
Cabré, A., Marinov, I., Bernardello, R., and Bianchi, D.: Oxygen minimum zones in the tropical Pacific across CMIP5 models: mean state differences and climate change trends, Biogeosciences, 12, 5429–5454, https://doi.org/10.5194/bg-12-5429-2015, 2015.
Carini, P., Dupont, C. L., and Santoro, A. E.: Patterns of thaumarchaeal gene expression in culture and diverse marine environments, Environ. Microbiol., 20, 2112–2124, https://doi.org/10.1111/1462-2920.14107, 2018.
Casciotti, K. L.: Nitrite isotopes as tracers of marine N cycle processes, Philos. T. R. Soc. A, 374, 20150295, https://doi.org/10.1098/rsta.2015.0295, 2016.
Casciotti, K. L., Sigman, D. M., Hastings, M. G., Böhlke, J. K., and Hilkert, A.: Measurement of the Oxygen Isotopic Composition of Nitrate in Seawater and Freshwater Using the Denitrifier Method, Anal. Chem., 74, 4905–4912, https://doi.org/10.1021/ac020113w, 2002.
Casciotti, K. L., Böhlke, J. K., McIlvin, M. R., Mroczkowski, S. J., and Hannon, J. E.: Oxygen Isotopes in Nitrite: Analysis, Calibration, and Equilibration, Anal. Chem., 79, 2427–2436, https://doi.org/10.1021/ac061598h, 2007.
Casciotti, K. L., Forbes, M., Vedamati, J., Peters, B. D., Martin, T. S., and Mordy, C. W.: Nitrous oxide cycling in the Eastern Tropical South Pacific as inferred from isotopic and isotopomeric data, Deep-Sea Res. Pt. II, 156, 155–167, https://doi.org/10.1016/j.dsr2.2018.07.014, 2018.
Codispoti, L. A. and Christensen, J. P.: Nitrification, denitrification and nitrous oxide cycling in the eastern tropical South Pacific ocean, Mar. Chem., 16, 277–300, https://doi.org/10.1016/0304-4203(85)90051-9, 1985.
Cohen, Y. and Gordon, L. I.: Nitrous oxide production in the Ocean, J. Geophys. Res.-Ocean., 84, 347–353, https://doi.org/10.1029/JC084iC01p00347, 1979.
Dalsgaard, T., Stewart, F. J., Thamdrup, B., Brabandere, L. D., Revsbech, N. P., Ulloa, O., Canfield, D. E., and DeLong, E. F.: Oxygen at Nanomolar Levels Reversibly Suppresses Process Rates and Gene Expression in Anammox and Denitrification in the Oxygen Minimum Zone off Northern Chile, mBio, 5, e01966-14, https://doi.org/10.1128/mBio.01966-14, 2014.
Farías, L., Castro-González, M., Cornejo, M., Charpentier, J., Faúndez, J., Boontanon, N., and Yoshida, N.: Denitrification and nitrous oxide cycling within the upper oxycline of the eastern tropical South Pacific oxygen minimum zone, Limnol. Oceanogr., 54, 132–144, https://doi.org/10.4319/lo.2009.54.1.0132, 2009.
Farías, L., Faúndez, J., Fernández, C., Cornejo, M., Sanhueza, S., and Carrasco, C.: Biological N2O fixation in the Eastern South Pacific Ocean and marine cyanobacterial cultures, PloS One, 8, e63956, https://doi.org/10.1371/journal.pone.0063956, 2013.
Frame, C. H. and Casciotti, K. L.: Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium, Biogeosciences, 7, 2695–2709, https://doi.org/10.5194/bg-7-2695-2010, 2010.
Frame, C. H., Lau, E., Nolan, E. J. I., Goepfert, T. J., and Lehmann, M. F.: Acidification Enhances Hybrid N2O Production Associated with Aquatic Ammonia-Oxidizing Microorganisms, Front. Microbiol., 7, 2104, https://doi.org/10.3389/fmicb.2016.02104, 2017.
Frey, C., Bange, H. W., Achterberg, E. P., Jayakumar, A., Löscher, C. R., Arévalo-Martínez, D. L., León-Palmero, E., Sun, M., Sun, X., Xie, R. C., Oleynik, S., and Ward, B. B.: Regulation of nitrous oxide production in low-oxygen waters off the coast of Peru, Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, 2020.
Frey, C., Sun, X., Szemberski, L., Casciotti, K. L., Garcia-Robledo, E., Jayakumar, A., Kelly, C. L., Lehmann, M. F., and Ward, B. B.: Kinetics of nitrous oxide production from ammonia oxidation in the Eastern Tropical North Pacific, Limnol. Oceanogr., 68, 424–438, https://doi.org/10.1002/lno.12283, 2023.
Garcia, H. E. and Gordon, L. I.: Oxygen Solubility in Seawater: Better Fitting Equations, Limnol. Oceanogr., 37, 1307–1312, 1992.
Goreau, T. J., Kaplan, W. A., Wofsy, S. C., McElroy, M. B., Valois, F. W., and Watson, S. W.: Production of NO
Granger, J. and Sigman, D. M.: Removal of nitrite with sulfamic acid for nitrate N and O isotope analysis with the denitrifier method, Rapid Commun. Mass Sp., 23, 3753–3762, https://doi.org/10.1002/rcm.4307, 2009.
Grasshoff, K., Ehrhardt, M., Kremling, K., and Anderson, L. G. (Eds.): Methods of seawater analysis, 3rd, completely rev. and extended ed ed., Wiley-VCH, Weinheim, New York, 600 pp., 1999.
Hink, L., Nicol, G. W., and Prosser, J. I.: Archaea produce lower yields of N 2 O than bacteria during aerobic ammonia oxidation in soil: N 2 O production by soil ammonia oxidisers, Environ. Microbiol., 19, 4829–4837, https://doi.org/10.1111/1462-2920.13282, 2017a.
Hink, L., Lycus, P., Gubry-Rangin, C., Frostegård, Å., Nicol, G. W., Prosser, J. I., and Bakken, L. R.: Kinetics of NH3-oxidation, NO-turnover, N2O-production and electron flow during oxygen depletion in model bacterial and archaeal ammonia oxidisers, Environ. Microbiol., 19, 4882–4896, https://doi.org/10.1111/1462-2920.13914, 2017b.
Holmes, R. M., Aminot, A., Kérouel, R., Hooker, B. A., and Peterson, B. J.: A simple and precise method for measuring ammonium in marine and freshwater ecosystems, Can. J. Fish. Aquat. Sci., 56, 1801–1808, https://doi.org/10.1139/f99-128, 1999.
Ji, Q., Babbin, A. R., Jayakumar, A., Oleynik, S., and Ward, B. B.: Nitrous oxide production by nitrification and denitrification in the Eastern Tropical South Pacific oxygen minimum zone, Geophys. Res. Lett., 42, 10755–10764, https://doi.org/10.1002/2015GL066853, 2015.
Ji, Q., Buitenhuis, E., Suntharalingam, P., Sarmiento, J. L., and Ward, B. B.: Global Nitrous Oxide Production Determined by Oxygen Sensitivity of Nitrification and Denitrification, Global Biogeochem. Cy., 32, 1790–1802, https://doi.org/10.1029/2018GB005887, 2018.
Kaiser, J., Park, S., Boering, K. A., Brenninkmeijer, C. A. M., Hilkert, A., and Röckmann, T.: Mass spectrometric method for the absolute calibration of the intramolecular nitrogen isotope distribution in nitrous oxide, Anal. Bioanal. Chem., 378, 256–269, https://doi.org/10.1007/s00216-003-2233-2, 2004.
Kantnerová, K., Hattori, S., Toyoda, S., Yoshida, N., Emmenegger, L., Bernasconi, S. M., and Mohn, J.: Clumped isotope signatures of nitrous oxide formed by bacterial denitrification, Geochim. Cosmochim. Ac., 328, 120–129, https://doi.org/10.1016/j.gca.2022.05.006, 2022.
Kelly, C. L.: ckelly314/pyisotopomer: v1.0.4, Zenodo [code], https://doi.org/10.5281/zenodo.7552724, 2023.
Kelly, C. L.: ckelly314/isotopomer-soup: Second release of isotopomer-soup (v0.0.2), Zenodo [code], https://doi.org/10.5281/zenodo.11475416, 2024.
Kelly, C. L. and Casciotti, K. L.: Data in support of “Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production” from the Eastern Tropical North Pacific, Stanford Digital Repository [data set], https://doi.org/10.25740/ss974md4840, 2023.
Kelly, C. L., Travis, N. M., Baya, P. A., and Casciotti, K. L.: Quantifying Nitrous Oxide Cycling Regimes in the Eastern Tropical North Pacific Ocean With Isotopomer Analysis, Global Biogeochem. Cy., 35, e2020GB006637, https://doi.org/10.1029/2020GB006637, 2021.
Kelly, C. L., Manning, C., Frey, C., Kaiser, J., Gluschankoff, N., and Casciotti, K. L.: Pyisotopomer: A Python package for obtaining intramolecular isotope ratio differences from mass spectrometric analysis of nitrous oxide isotopocules, Rapid Commun. Mass Sp., 37, e9513, https://doi.org/10.1002/rcm.9513, 2023.
Kim, K.-R. and Craig, H.: Two-isotope characterization of N2O in the Pacific Ocean and constraints on its origin in deep water, Nature, 347, 58–61, https://doi.org/10.1038/347058a0, 1990.
Kozlowski, J. A., Kits, K. D., and Stein, L. Y.: Comparison of Nitrogen Oxide Metabolism among Diverse Ammonia-Oxidizing Bacteria, Front. Microbiol., 7, 1090, https://doi.org/10.3389/fmicb.2016.01090, 2016.
Kraft, B., Jehmlich, N., Larsen, M., Bristow, L. A., Könneke, M., Thamdrup, B., and Canfield, D. E.: Oxygen and nitrogen production by an ammonia-oxidizing archaeon, Science, 375, 97–100, https://doi.org/10.1126/science.abe6733, 2022.
Kuypers, M. M. M., Marchant, H. K., and Kartal, B.: The microbial nitrogen-cycling network, Nat. Rev. Microbiol., 16, 263–276, https://doi.org/10.1038/nrmicro.2018.9, 2018.
Lancaster, K. M., Caranto, J. D., Majer, S. H., and Smith, M. A.: Alternative Bioenergy: Updates to and Challenges in Nitrification Metalloenzymology, Joule, 2, 421–441, https://doi.org/10.1016/j.joule.2018.01.018, 2018.
Lazo-Murphy, B. M., Larson, S., Staines, S., Bruck, H., McHenry, J., Bourbonnais, A., and Peng, X.: Nitrous oxide production and isotopomer composition by fungi isolated from salt marsh sediments, Front. Mar. Sci., 9, 1098508, https://doi.org/10.3389/fmars.2022.1098508, 2022.
Lipschultz, F.: Chap. 31 – Isotope Tracer Methods for Studies of the Marine Nitrogen Cycle, in: Nitrogen in the Marine Environment, 2nd Edn., edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and Carpenter, E. J., Academic Press, San Diego, 1345–1384, https://doi.org/10.1016/B978-0-12-372522-6.00031-1, 2008.
Magyar, P. M., Orphan, V. J., and Eiler, J. M.: Measurement of rare isotopologues of nitrous oxide by high-resolution multi-collector mass spectrometry, Rapid Commun. Mass Sp., 30, 1923–1940, https://doi.org/10.1002/rcm.7671, 2016.
Martens-Habbena, W., Qin, W., Horak, R. E. A., Urakawa, H., Schauer, A. J., Moffett, J. W., Armbrust, E. V., Ingalls, A. E., Devol, A. H., and Stahl, D. A.: The production of nitric oxide by marine ammonia-oxidizing archaea and inhibition of archaeal ammonia oxidation by a nitric oxide scavenger, Environ. Microbiol., 17, 2261–2274, https://doi.org/10.1111/1462-2920.12677, 2015.
McIlvin, M. R. and Altabet, M. A.: Chemical Conversion of Nitrate and Nitrite to Nitrous Oxide for Nitrogen and Oxygen Isotopic Analysis in Freshwater and Seawater, Anal. Chem., 77, 5589–5595, https://doi.org/10.1021/ac050528s, 2005.
McIlvin, M. R. and Casciotti, K. L.: Fully automated system for stable isotopic analyses of dissolved nitrous oxide at natural abundance levels, Limnol. Oceanogr. Method., 8, 54–66, https://doi.org/10.4319/lom.2010.8.54, 2010.
McIlvin, M. R. and Casciotti, K. L.: Technical updates to the bacterial method for nitrate isotopic analyses, Anal. Chem., 83, 1850–1856, https://doi.org/10.1021/ac1028984, 2011.
Monreal, P. J., Kelly, C. L., Travis, N. M., and Casciotti, K. L.: Identifying the Sources and Drivers of Nitrous Oxide Accumulation in the Eddy-Influenced Eastern Tropical North Pacific Oxygen-Deficient Zone, Global Biogeochem. Cy., 36, e2022GB007310, https://doi.org/10.1029/2022GB007310, 2022.
Naqvi, S. W. A., Jayakumar, D. A., Narvekar, P. V., Naik, H., Sarma, V. V. S. S., D'Souza, W., Joseph, S., and George, M. D.: Increased marine production of N2O due to intensifying anoxia on the Indian continental shelf, Nature, 408, 346–349, https://doi.org/10.1038/35042551, 2000.
Nelder, J. A. and Mead, R.: A Simplex Method for Function Minimization, Comput. J., 7, 308–313, https://doi.org/10.1093/comjnl/7.4.308, 1965.
Nevison, C., Butler, J. H., and Elkins, J. W.: Global distribution of N2O and the Delta N2O-AOU yield in the subsurface ocean, Global Biogeochem. Cy., 17, 1119, https://doi.org/10.1029/2003GB002068, 2003.
NOAA/National Weather Service: Cold and Warm Episodes by Season, National Weather Service Climate Prediction Center [data set], https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php, last access: 20 July 2020.
Oschlies, A., Brandt, P., Stramma, L., and Schmidtko, S.: Drivers and mechanisms of ocean deoxygenation, Nat. Geosci., 11, 467–473, https://doi.org/10.1038/s41561-018-0152-2, 2018.
Peng, X. and Valentine, D. L.: Diversity and N2O Production Potential of Fungi in an Oceanic Oxygen Minimum Zone, J. Fungi, 7, 218, https://doi.org/10.3390/jof7030218, 2021.
Popp, B. N., Westley, M. B., Toyoda, S., Miwa, T., Dore, J. E., Yoshida, N., Rust, T. M., Sansone, F. J., Russ, M. E., Ostrom, N. E., and Ostrom, P. H.: Nitrogen and oxygen isotopomeric constraints on the origins and sea-to-air flux of N2O in the oligotrophic subtropical North Pacific gyre, Global Biogeochem. Cy., 16, 12-1–12-10, https://doi.org/10.1029/2001GB001806, 2002.
Rahn, T. and Wahlen, M.: A reassessment of the global isotopic budget of atmospheric nitrous oxide, Global Biogeochem. Cy., 14, 537–543, https://doi.org/10.1029/1999GB900070, 2000.
Rohe, L., Anderson, T.-H., Braker, G., Flessa, H., Giesemann, A., Lewicka-Szczebak, D., Wrage-Mönnig, N., and Well, R.: Dual isotope and isotopomer signatures of nitrous oxide from fungal denitrification – a pure culture study, Rapid Commun. Mass Sp., 28, 1893–1903, https://doi.org/10.1002/rcm.6975, 2014.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic oxygen content during the past five decades, Nature, 542, 335–339, https://doi.org/10.1038/nature21399, 2017.
Shoun, H., Fushinobu, S., Jiang, L., Kim, S.-W., and Wakagi, T.: Fungal denitrification and nitric oxide reductase cytochrome P450nor, Philos. Trans. Biol. Sci., 367, 1186–1194, 2012.
Si, Y., Zhu, Y., Sanders, I., Kinkel, D. B., Purdy, K. J., and Trimmer, M.: Direct biological fixation provides a freshwater sink for N2O, Nat. Commun., 14, 6775, https://doi.org/10.1038/s41467-023-42481-2, 2023.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M., and Böhlke, J. K.: A Bacterial Method for the Nitrogen Isotopic Analysis of Nitrate in Seawater and Freshwater, Anal. Chem., 73, 4145–4153, https://doi.org/10.1021/ac010088e, 2001.
Smith, C., Nicholls, Z. R. J., Armour, K., Collins, W., Dufresne, J.-L., Frame, D., Lunt, D. J., Mauritsen, M. D., Palmer, M. D., Watanabe, M., Wild, M., and Zhang, H.: The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity Supplementary Material, in: Climate Change 2021: The Physical Science Basis, Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., Cambridge University Press, Cambridge, United Kingdom, ISBN: 978-1-00-915789-6, https://doi.org/10.1017/9781009157896, 2021.
Smriga, S., Ciccarese, D., and Babbin, A. R.: Denitrifying bacteria respond to and shape microscale gradients within particulate matrices, Commun. Biol., 4, 570, https://doi.org/10.1038/s42003-021-02102-4, 2021.
Stein, L. Y.: Insights into the physiology of ammonia-oxidizing microorganisms, Curr. Opin. Chem. Biol., 49, 9–15, https://doi.org/10.1016/j.cbpa.2018.09.003, 2019.
Stein, L. Y. and Yung, Y. L.: Production, Isotopic Composition, and Atmospheric Fate of Biologically Produced Nitrous Oxide, Annu. Rev. Earth Pl. Sc., 31, 329–356, https://doi.org/10.1146/annurev.earth.31.110502.080901, 2003.
Stieglmeier, M., Mooshammer, M., Kitzler, B., Wanek, W., Zechmeister-Boltenstern, S., Richter, A., and Schleper, C.: Aerobic nitrous oxide production through N-nitrosating hybrid formation in ammonia-oxidizing archaea, ISME J., 8, 1135–1146, https://doi.org/10.1038/ismej.2013.220, 2014.
Stramma, L., Johnson, G. C., Sprintall, J., and Mohrholz, V.: Expanding Oxygen-Minimum Zones in the Tropical Oceans, Science, 320, 655–658, https://doi.org/10.1126/science.1153847, 2008.
Sun, X., Ji, Q., Jayakumar, A., and Ward, B. B.: Dependence of nitrite oxidation on nitrite and oxygen in low-oxygen seawater, Geophys. Res. Lett., 44, 7883–7891, https://doi.org/10.1002/2017GL074355, 2017.
Sun, X., Jayakumar, A., Tracey, J. C., Wallace, E., Kelly, C. L., Casciotti, K. L., and Ward, B. B.: Microbial N2O consumption in and above marine N2O production hotspots, ISME J., 15, 1434–1444, https://doi.org/10.1038/s41396-020-00861-2, 2021a.
Sun, X., Frey, C., Garcia-Robledo, E., Jayakumar, A., and Ward, B. B.: Microbial niche differentiation explains nitrite oxidation in marine oxygen minimum zones, ISME J., 15, 1317–1329, https://doi.org/10.1038/s41396-020-00852-3, 2021b.
Sutka, R. L., Ostrom, N. E., Ostrom, P. H., Gandhi, H., and Breznak, J. A.: Nitrogen isotopomer site preference of N2O produced by Nitrosomonas europaea and Methylococcus capsulatus Bath, Rapid Commun. Mass Sp., 17, 738–745, https://doi.org/10.1002/rcm.968, 2003.
Sutka, R. L., Ostrom, N. E., Ostrom, P. H., Gandhi, H., and Breznak, J. A.: Nitrogen isotopomer site preference of N2O produced by Nitrosomonas europaea and Methylococcus capsulatus Bath, Rapid Commun. Mass Sp., 18, 1411–1412, https://doi.org/10.1002/rcm.1482, 2004.
Sutka, R. L., Ostrom, N. E., Ostrom, P. H., Breznak, J. A., Gandhi, H., Pitt, A. J., and Li, F.: Distinguishing Nitrous Oxide Production from Nitrification and Denitrification on the Basis of Isotopomer Abundances, Appl. Environ. Microbiol., 72, 638–644, https://doi.org/10.1128/AEM.72.1.638-644.2006, 2006.
Sutka, R. L., Adams, G. C., Ostrom, N. E., and Ostrom, P. H.: Isotopologue fractionation during N2O production by fungal denitrification, Rapid Commun. Mass Sp., 22, 3989–3996, https://doi.org/10.1002/rcm.3820, 2008.
Tian, H., Xu, R., Canadell, J. G., Thompson, R. L., Winiwarter, W., Suntharalingam, P., Davidson, E. A., Ciais, P., Jackson, R. B., Janssens-Maenhout, G., Prather, M. J., Regnier, P., Pan, N., Pan, S., Peters, G. P., Shi, H., Tubiello, F. N., Zaehle, S., Zhou, F., Arneth, A., Battaglia, G., Berthet, S., Bopp, L., Bouwman, A. F., Buitenhuis, E. T., Chang, J., Chipperfield, M. P., Dangal, S. R. S., Dlugokencky, E., Elkins, J. W., Eyre, B. D., Fu, B., Hall, B., Ito, A., Joos, F., Krummel, P. B., Landolfi, A., Laruelle, G. G., Lauerwald, R., Li, W., Lienert, S., Maavara, T., MacLeod, M., Millet, D. B., Olin, S., Patra, P. K., Prinn, R. G., Raymond, P. A., Ruiz, D. J., van der Werf, G. R., Vuichard, N., Wang, J., Weiss, R. F., Wells, K. C., Wilson, C., Yang, J., and Yao, Y.: A comprehensive quantification of global nitrous oxide sources and sinks, Nature, 586, 248–256, https://doi.org/10.1038/s41586-020-2780-0, 2020.
Toyoda, S. and Yoshida, N.: Determination of nitrogen isotopomers of nitrous oxide on a modified isotope ratio mass spectrometer, Anal. Chem., 71, 4711–4718, https://doi.org/10.1021/ac9904563, 1999.
Toyoda, S., Yoshida, N., Miwa, T., Matsui, Y., Yamagishi, H., Tsunogai, U., Nojiri, Y., and Tsurushima, N.: Production mechanism and global budget of N2O inferred from its isotopomers in the western North Pacific, Geophys. Res. Lett., 29, 7-1–7-4, https://doi.org/10.1029/2001GL014311, 2002.
Toyoda, S., Mutobe, H., Yamagishi, H., Yoshida, N., and Tanji, Y.: Fractionation of N2O isotopomers during production by denitrifier, Soil Biol. Biochem., 37, 1535–1545, https://doi.org/10.1016/j.soilbio.2005.01.009, 2005.
Toyoda, S., Yoshida, O., Yamagishi, H., Fujii, A., Yoshida, N., and Watanabe, S.: Identifying the origin of nitrous oxide dissolved in deep ocean by concentration and isotopocule analyses, Sci. Rep., 9, 1–9, https://doi.org/10.1038/s41598-019-44224-0, 2019.
Toyoda, S., Kakimoto, T., Kudo, K., Yoshida, N., Sasano, D., Kosugi, N., Ishii, M., Kameyama, S., Inagawa, M., Yoshikawa-Inoue, H., Nishino, S., Murata, A., Ishidoya, S., and Morimoto, S.: Distribution and Production Mechanisms of N2O in the Western Arctic Ocean, Global Biogeochem. Cy., 35, e2020GB006881, https://doi.org/10.1029/2020GB006881, 2021.
Toyoda, S., Terajima, K., Yoshida, N., Yoshikawa, C., Makabe, A., Hashihama, F., and Ogawa, H.: Extensive Accumulation of Nitrous Oxide in the Oxygen Minimum Zone in the Bay of Bengal, Global Biogeochem. Cy., 37, e2022GB007689, https://doi.org/10.1029/2022GB007689, 2023.
Travis, N. M., Kelly, C. L., Mulholland, M. R., and Casciotti, K. L.: Nitrite cycling in the primary nitrite maxima of the eastern tropical North Pacific, Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, 2023.
Trimmer, M., Chronopoulou, P.-M., Maanoja, S. T., Upstill-Goddard, R. C., Kitidis, V., and Purdy, K. J.: Nitrous oxide as a function of oxygen and archaeal gene abundance in the North Pacific, Nat. Commun., 7, 13451–13451, https://doi.org/10.1038/ncomms13451, 2016.
Vajrala, N., Martens-Habbena, W., Sayavedra-Soto, L. A., Schauer, A., Bottomley, P. J., Stahl, D. A., and Arp, D. J.: Hydroxylamine as an intermediate in ammonia oxidation by globally abundant marine archaea, P. Natl. Acad. Sci. USA, 110, 1006–1011, 2013.
Virtanen, P., Gommers, R., Oliphant, T. E., Haberland, M., Reddy, T., Cournapeau, D., Burovski, E., Peterson, P., Weckesser, W., Bright, J., van der Walt, S. J., Brett, M., Wilson, J., Millman, K. J., Mayorov, N., Nelson, A. R. J., Jones, E., Kern, R., Larson, E., Carey, C. J., Polat, İ., Feng, Y., Moore, E. W., VanderPlas, J., Laxalde, D., Perktold, J., Cimrman, R., Henriksen, I., Quintero, E. A., Harris, C. R., Archibald, A. M., Ribeiro, A. H., Pedregosa, F., and van Mulbregt, P.: SciPy 1.0: fundamental algorithms for scientific computing in Python, Nat. Method., 17, 261–272, https://doi.org/10.1038/s41592-019-0686-2, 2020.
Wan, X. S., Sheng, H.-X., Liu, L., Shen, H., Tang, W., Zou, W., Xu, M. N., Zheng, Z., Tan, E., Chen, M., Zhang, Y., Ward, B. B., and Kao, S.-J.: Particle-associated denitrification is the primary source of N2O in oxic coastal waters, Nat. Commun., 14, 8280, https://doi.org/10.1038/s41467-023-43997-3, 2023a.
Wan, X. S., Hou, L., Kao, S.-J., Zhang, Y., Sheng, H.-X., Shen, H., Tong, S., Qin, W., and Ward, B. B.: Pathways of N2O production by marine ammonia-oxidizing archaea determined from dual-isotope labeling, P. Natl. Acad. Sci. USA, 120, e2220697120, https://doi.org/10.1073/pnas.2220697120, 2023b.
Wang, R. Z., Lonergan, Z. R., Wilbert, S. A., Eiler, J. M., and Newman, D. K.: Widespread detoxifying NO reductases impart a distinct isotopic fingerprint on N 2O under anoxia, Microbiology, bioRxiv 2023.10.13.562248, https://doi.org/10.1101/2023.10.13.562248, 2023.
Wei, J., Ibraim, E., Brüggemann, N., Vereecken, H., and Mohn, J.: First real-time isotopic characterisation of N2O from chemodenitrification, Geochim. Cosmochim. Ac., 267, 17–32, https://doi.org/10.1016/j.gca.2019.09.018, 2019.
Westley, M. B., Yamagishi, H., Popp, B. N., and Yoshida, N.: Nitrous oxide cycling in the Black Sea inferred from stable isotope and isotopomer distributions, Deep-Sea Res. Pt. II, 53, 1802–1816, https://doi.org/10.1016/j.dsr2.2006.03.012, 2006.
Wrage, N., Velthof, G. L., Van Beusichem, M. L., and Oenema, O.: Role of nitrifier denitrification in the production of nitrous oxide, Soil Biol. Biochem., 33, 1723–1732, https://doi.org/10.1016/S0038-0717(01)00096-7, 2001.
Yamagishi, H., Westley, M. B., Popp, B. N., Toyoda, S., Yoshida, N., Watanabe, S., Koba, K., and Yamanaka, Y.: Role of nitrification and denitrification on the nitrous oxide cycle in the eastern tropical North Pacific and Gulf of California, J. Geophys. Res.-Biogeo., 112, G02015, https://doi.org/10.1029/2006JG000227, 2007.
Yang, H., Gandhi, H., Ostrom, N. E., and Hegg, E. L.: Isotopic Fractionation by a Fungal P450 Nitric Oxide Reductase during the Production of N2O, Environ. Sci. Technol., 48, 10707–10715, https://doi.org/10.1021/es501912d, 2014.
Zumft, W. G.: Cell biology and molecular basis of denitrification, Microbiol. Mol. Biol. Rev., 61, 533–616, https://doi.org/10.1128/mmbr.61.4.533-616.1997, 1997.
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Short summary
Nitrous oxide, a potent greenhouse gas, accumulates in regions of the ocean that are low in dissolved oxygen. We used a novel combination of chemical tracers to determine how nitrous oxide is produced in one of these regions, the eastern tropical North Pacific Ocean. Our experiments showed that the two most important sources of nitrous oxide under low-oxygen conditions are denitrification, an anaerobic process, and a novel “hybrid” process performed by ammonia-oxidizing archaea.
Nitrous oxide, a potent greenhouse gas, accumulates in regions of the ocean that are low in...
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