Articles | Volume 20, issue 15
https://doi.org/10.5194/bg-20-3229-2023
© Author(s) 2023. 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-20-3229-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
07 Aug 2023
Research article |
| 07 Aug 2023
| 07 Aug 2023
Seasonal variability of nitrous oxide concentrations and emissions in a temperate estuary
Institute of Geology, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, 20146, Germany
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, 21502, Germany
Tina Sanders
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, 21502, Germany
Yoana G. Voynova
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, 21502, Germany
Hermann W. Bange
Marine Biogeochemistry Research Division, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, 24105, Germany
Kirstin Dähnke
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, 21502, Germany
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Hanna I. Campen, Damian L. Arévalo-Martínez, and Hermann W. Bange
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Damian L. Arévalo-Martínez, Amir Haroon, Hermann W. Bange, Ercan Erkul, Marion Jegen, Nils Moosdorf, Jens Schneider von Deimling, Christian Berndt, Michael Ernst Böttcher, Jasper Hoffmann, Volker Liebetrau, Ulf Mallast, Gudrun Massmann, Aaron Micallef, Holly A. Michael, Hendrik Paasche, Wolfgang Rabbel, Isaac Santos, Jan Scholten, Katrin Schwalenberg, Beata Szymczycha, Ariel T. Thomas, Joonas J. Virtasalo, Hannelore Waska, and Bradley A. Weymer
Biogeosciences, 20, 647–662, https://doi.org/10.5194/bg-20-647-2023, https://doi.org/10.5194/bg-20-647-2023, 2023
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Groundwater flows at the land–ocean transition and the extent of freshened groundwater below the seafloor are increasingly relevant in marine sciences, both because they are a highly uncertain term of biogeochemical budgets and due to the emerging interest in the latter as a resource. Here, we discuss our perspectives on future research directions to better understand land–ocean connectivity through groundwater and its potential responses to natural and human-induced environmental changes.
Kirstin Dähnke, Tina Sanders, Yoana Voynova, and Scott D. Wankel
Biogeosciences, 19, 5879–5891, https://doi.org/10.5194/bg-19-5879-2022, https://doi.org/10.5194/bg-19-5879-2022, 2022
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Nitrogen is an important macronutrient that fuels algal production in rivers and coastal regions. We investigated the production and removal of nitrogen-bearing compounds in the freshwater section of the tidal Elbe Estuary and found that particles in the water column are key for the production and removal of water column nitrate. Using a stable isotope approach, we pinpointed regions where additional removal of nitrate or input from sediments plays an important role in estuarine biogeochemistry.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
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Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
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Charlotte Haugk, Loeka L. Jongejans, Kai Mangelsdorf, Matthias Fuchs, Olga Ogneva, Juri Palmtag, Gesine Mollenhauer, Paul J. Mann, P. Paul Overduin, Guido Grosse, Tina Sanders, Robyn E. Tuerena, Lutz Schirrmeister, Sebastian Wetterich, Alexander Kizyakov, Cornelia Karger, and Jens Strauss
Biogeosciences, 19, 2079–2094, https://doi.org/10.5194/bg-19-2079-2022, https://doi.org/10.5194/bg-19-2079-2022, 2022
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Yanan Zhao, Dennis Booge, Christa A. Marandino, Cathleen Schlundt, Astrid Bracher, Elliot L. Atlas, Jonathan Williams, and Hermann W. Bange
Biogeosciences, 19, 701–714, https://doi.org/10.5194/bg-19-701-2022, https://doi.org/10.5194/bg-19-701-2022, 2022
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We present here, for the first time, simultaneously measured dimethylsulfide (DMS) seawater concentrations and DMS atmospheric mole fractions from the Peruvian upwelling region during two cruises in December 2012 and October 2015. Our results indicate low oceanic DMS concentrations and atmospheric DMS molar fractions in surface waters and the atmosphere, respectively. In addition, the Peruvian upwelling region was identified as an insignificant source of DMS emissions during both periods.
Wangwang Ye, Hermann W. Bange, Damian L. Arévalo-Martínez, Hailun He, Yuhong Li, Jianwen Wen, Jiexia Zhang, Jian Liu, Man Wu, and Liyang Zhan
Biogeosciences Discuss., https://doi.org/10.5194/bg-2021-334, https://doi.org/10.5194/bg-2021-334, 2022
Manuscript not accepted for further review
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CH4 is the second important greenhouse gas after CO2. We show that CH4 consumption and sea-ice melting influence the CH4 distribution in the Ross Sea (Southern Ocean), causing undersaturation and net uptake of CH4 during summertime. This study confirms the capability of surface water in the high-latitude Southern Ocean regions to take up atmospheric CH4 which, in turn, will help to improve predictions of how CH4 release/uptake from the ocean will develop when sea-ice retreats in the future.
Yanan Zhao, Cathleen Schlundt, Dennis Booge, and Hermann W. Bange
Biogeosciences, 18, 2161–2179, https://doi.org/10.5194/bg-18-2161-2021, https://doi.org/10.5194/bg-18-2161-2021, 2021
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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.
Onur Kerimoglu, Yoana G. Voynova, Fatemeh Chegini, Holger Brix, Ulrich Callies, Richard Hofmeister, Knut Klingbeil, Corinna Schrum, and Justus E. E. van Beusekom
Biogeosciences, 17, 5097–5127, https://doi.org/10.5194/bg-17-5097-2020, https://doi.org/10.5194/bg-17-5097-2020, 2020
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In this study, using extensive field observations and a numerical model, we analyzed the physical and biogeochemical structure of a coastal system following an extreme flood event. Our results suggest that a number of anomalous observations were driven by a co-occurrence of peculiar meteorological conditions and increased riverine discharges. Our results call for attention to the combined effects of hydrological and meteorological extremes that are anticipated to increase in frequency.
Xiao Ma, Mingshuang Sun, Sinikka T. Lennartz, and Hermann W. Bange
Biogeosciences, 17, 3427–3438, https://doi.org/10.5194/bg-17-3427-2020, https://doi.org/10.5194/bg-17-3427-2020, 2020
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Alexander Bratek, Justus E. E. van
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Biogeosciences, 17, 2839–2851, https://doi.org/10.5194/bg-17-2839-2020, https://doi.org/10.5194/bg-17-2839-2020, 2020
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The following paper highlights the importance of benthic N-transformation rates in different sediment types in the southern North Sea as a source of fixed nitrogen for primary producers and also as a sink of fixed nitrogen. Sedimentary fluxes of dissolved inorganic nitrogen support ∼7 to 59 % of the average annual primary production. Semi-permeable and permeable sediments contribute ∼68 % of the total benthic N2 production rates, counteracting eutrophication in the southern North Sea.
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.
Carolin R. Löscher, Wiebke Mohr, Hermann W. Bange, and Donald E. Canfield
Biogeosciences, 17, 851–864, https://doi.org/10.5194/bg-17-851-2020, https://doi.org/10.5194/bg-17-851-2020, 2020
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Oxygen minimum zones (OMZs) are ocean areas severely depleted in oxygen as a result of physical, chemical, and biological processes. Biologically, organic material is produced in the sea surface and exported to deeper waters, where it respires. In the Bay of Bengal (BoB), an OMZ is present, but there are traces of oxygen left. Our study now suggests that this is because one key process, nitrogen fixation, is absent in the BoB, thus preventing primary production and consecutive respiration.
Ye Tian, Gui-Peng Yang, Chun-Ying Liu, Pei-Feng Li, Hong-Tao Chen, and Hermann W. Bange
Ocean Sci., 16, 135–148, https://doi.org/10.5194/os-16-135-2020, https://doi.org/10.5194/os-16-135-2020, 2020
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Nitric oxide (NO) could be produced by nitrite photolysis; the rates from dissolved nitrite in artificial seawater showed increasing trends with decreasing pH, increasing temperatures, and increasing salinity. However, NO photoproduction from the natural seawater samples did not show correlations with pH, water temperature, salinity, or dissolved nitrite concentrations in the western tropical North Pacific Ocean (WNTP). And there were other NO loss processes in the surface layer of WNTP.
Thomas Holding, Ian G. Ashton, Jamie D. Shutler, Peter E. Land, Philip D. Nightingale, Andrew P. Rees, Ian Brown, Jean-Francois Piolle, Annette Kock, Hermann W. Bange, David K. Woolf, Lonneke Goddijn-Murphy, Ryan Pereira, Frederic Paul, Fanny Girard-Ardhuin, Bertrand Chapron, Gregor Rehder, Fabrice Ardhuin, and Craig J. Donlon
Ocean Sci., 15, 1707–1728, https://doi.org/10.5194/os-15-1707-2019, https://doi.org/10.5194/os-15-1707-2019, 2019
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FluxEngine is an open-source software toolbox designed to allow for the easy and accurate calculation of air–sea gas fluxes. This article describes new functionality and capabilities, which include the ability to calculate fluxes for nitrous oxide and methane, optimisation for running FluxEngine on a stand-alone desktop computer, and extensive new features to support the in situ measurement community. Four research case studies are used to demonstrate these new features.
Ye Tian, Chao Xue, Chun-Ying Liu, Gui-Peng Yang, Pei-Feng Li, Wei-Hua Feng, and Hermann W. Bange
Biogeosciences, 16, 4485–4496, https://doi.org/10.5194/bg-16-4485-2019, https://doi.org/10.5194/bg-16-4485-2019, 2019
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Nitric oxide (NO) seems to be widespread, with different functions in the marine ecosystem, but we know little about it. Concentrations of NO were in a range from below the limit of detection to 616 pmol L−1 at the surface and 482 pmol L−1 at the bottom of the Bohai and Yellow seas. The study region was a source of atmospheric NO. Net NO sea-to-air fluxes were much lower than NO photoproduction rates, implying that the NO produced in the mixed layer was rapidly consumed before entering the air.
Hermann W. Bange, Chun Hock Sim, Daniel Bastian, Jennifer Kallert, Annette Kock, Aazani Mujahid, and Moritz Müller
Biogeosciences, 16, 4321–4335, https://doi.org/10.5194/bg-16-4321-2019, https://doi.org/10.5194/bg-16-4321-2019, 2019
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Nitrous oxide (N2O) and methane (CH4) are atmospheric trace gases which play important roles in the climate and atmospheric chemistry of the Earth. However, little is known about their emissions from rivers and estuaries. To this end, concentrations of N2O and CH4 were measured during a seasonal study in six rivers and estuaries in northwestern Borneo. The concentrations of both gases were mainly driven by rainfall. The rivers and estuaries were an overall net source of atmospheric N2O and CH4.
Xiao Ma, Sinikka T. Lennartz, and Hermann W. Bange
Biogeosciences, 16, 4097–4111, https://doi.org/10.5194/bg-16-4097-2019, https://doi.org/10.5194/bg-16-4097-2019, 2019
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Monthly measurements of nitrous oxide (N2O), a potent greenhouse gas and ozone depletion agent, were conducted at Boknis Eck (BE), a time series station in the southwestern Baltic Sea, since July 2005. Low N2O concentrations were observed in autumn and high in winter and early spring. Dissolved nutrients and oxygen played important roles in N2O distribution. Although we did not observe a significant N2O trend during 2005–2017, a decrease in N2O concentration and emission seems likely in future.
Eric J. Morgan, Jost V. Lavric, Damian L. Arévalo-Martínez, Hermann W. Bange, Tobias Steinhoff, Thomas Seifert, and Martin Heimann
Biogeosciences, 16, 4065–4084, https://doi.org/10.5194/bg-16-4065-2019, https://doi.org/10.5194/bg-16-4065-2019, 2019
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Taking a 2-year atmospheric record of atmospheric oxygen and the greenhouse gases N2O, CO2, and CH4, made at a coastal site in the Namib Desert, we estimated the fluxes of these gases from upwelling events in the northern Benguela Current region. We compared these results with flux measurements made on a research vessel in the study area at the same time and found that the two approaches agreed well. The study region was a source of N2O, CO2, and CH4 to the atmosphere during upwelling events.
Natalie C. Harms, Niko Lahajnar, Birgit Gaye, Tim Rixen, Kirstin Dähnke, Markus Ankele, Ulrich Schwarz-Schampera, and Kay-Christian Emeis
Biogeosciences, 16, 2715–2732, https://doi.org/10.5194/bg-16-2715-2019, https://doi.org/10.5194/bg-16-2715-2019, 2019
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The Indian Ocean subtropical gyre is a large oligotrophic area that is likely to adjust to continued warming by increasing stratification, reduced nutrient supply and decreasing biological production. In this study, we investigated concentrations of nutrients and stable isotopes of nitrate. We determine the lateral influence of water masses entering the gyre from the northern Indian Ocean and from the Southern Ocean and quantify the input of nitrogen by N2 fixation into the surface layer.
Johannes Pein, Annika Eisele, Richard Hofmeister, Tina Sanders, Ute Daewel, Emil V. Stanev, Justus van Beusekom, Joanna Staneva, and Corinna Schrum
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-265, https://doi.org/10.5194/bg-2019-265, 2019
Revised manuscript not accepted
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The Elbe estuary is subject to vigorous tidal forcing from the sea side and considerable biological inputs from the land side. Our 3D numerical coupled physical-biogeochemical integrates these forcing signals and provides highly realistic hindcasts of the associated dynamics. Model simulations show that the freshwater part of Elbe estuary is inhabited by plankton. According to simulations these organism play a key role in converting organic inputs into nitrate, the major inorganic nutrient.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328, https://doi.org/10.5194/bg-16-2307-2019, https://doi.org/10.5194/bg-16-2307-2019, 2019
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We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Qixing Ji, Mark A. Altabet, Hermann W. Bange, Michelle I. Graco, Xiao Ma, Damian L. Arévalo-Martínez, and Damian S. Grundle
Biogeosciences, 16, 2079–2093, https://doi.org/10.5194/bg-16-2079-2019, https://doi.org/10.5194/bg-16-2079-2019, 2019
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A strong El Niño event occurred in the Peruvian coastal region in 2015–2016, during which higher sea surface temperatures co-occurred with significantly lower sea-to-air fluxes of nitrous oxide, an important greenhouse gas and ozone depletion agent. Stratified water column during El Niño retained a larger amount of nitrous oxide that was produced via multiple microbial pathways; and intense nitrous oxide effluxes could occur when normal upwelling is resumed after El Niño.
Samuel T. Wilson, Hermann W. Bange, Damian L. Arévalo-Martínez, Jonathan Barnes, Alberto V. Borges, Ian Brown, John L. Bullister, Macarena Burgos, David W. Capelle, Michael Casso, Mercedes de la Paz, Laura Farías, Lindsay Fenwick, Sara Ferrón, Gerardo Garcia, Michael Glockzin, David M. Karl, Annette Kock, Sarah Laperriere, Cliff S. Law, Cara C. Manning, Andrew Marriner, Jukka-Pekka Myllykangas, John W. Pohlman, Andrew P. Rees, Alyson E. Santoro, Philippe D. Tortell, Robert C. Upstill-Goddard, David P. Wisegarver, Gui-Ling Zhang, and Gregor Rehder
Biogeosciences, 15, 5891–5907, https://doi.org/10.5194/bg-15-5891-2018, https://doi.org/10.5194/bg-15-5891-2018, 2018
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To determine the variability between independent measurements of dissolved methane and nitrous oxide, seawater samples were analyzed by multiple laboratories. The results revealed the influences of the different parts of the analytical process, from the initial sample collection to the calculation of the final concentrations. Recommendations are made to improve dissolved methane and nitrous oxide measurements to help preclude future analytical discrepancies between laboratories.
Johanna Maltby, Lea Steinle, Carolin R. Löscher, Hermann W. Bange, Martin A. Fischer, Mark Schmidt, and Tina Treude
Biogeosciences, 15, 137–157, https://doi.org/10.5194/bg-15-137-2018, https://doi.org/10.5194/bg-15-137-2018, 2018
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The activity and environmental controls of methanogenesis (MG) within the sulfate-reducing zone (0–30 cm below the seafloor) were investigated in organic-rich sediments of the seasonally hypoxic Eckernförde Bay, SW Baltic Sea. MG activity was mostly linked to non-competitive substrates. The major controls identified were organic matter availability, C / N, temperature, and O2 in the water column, revealing higher rates in warm, stratified, hypoxic seasons compared to colder, oxygenated seasons.
Chun-Ying Liu, Wei-Hua Feng, Ye Tian, Gui-Peng Yang, Pei-Feng Li, and Hermann W. Bange
Ocean Sci., 13, 623–632, https://doi.org/10.5194/os-13-623-2017, https://doi.org/10.5194/os-13-623-2017, 2017
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We developed a new method for the determination of dissolved nitric oxide (NO) in discrete seawater samples based on the combination of a purge-and-trap setup and a fluorometric detection of NO. With this method we have a reliable and comparably easy to use method to measure oceanic NO surface concentrations, which can be used to decipher both its temporal and spatial distributions as well as its biogeochemical pathways in the oceans.
Lea Steinle, Johanna Maltby, Tina Treude, Annette Kock, Hermann W. Bange, Nadine Engbersen, Jakob Zopfi, Moritz F. Lehmann, and Helge Niemann
Biogeosciences, 14, 1631–1645, https://doi.org/10.5194/bg-14-1631-2017, https://doi.org/10.5194/bg-14-1631-2017, 2017
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Large amounts of methane are produced in anoxic, coastal sediments, from which it can seep into the overlying water column. Aerobic oxidation of methane (MOx) mediated by methanotrophic bacteria is an important sink for methane before its evasion to the atmosphere. In a 2-year seasonal study, we investigated the spatio-temporal variability of MOx in a seasonally hypoxic coastal inlet using radiotracer-based methods. In experiments, we assessed the effect of variable oxygen concentrations on MOx.
Yoana G. Voynova, Holger Brix, Wilhelm Petersen, Sieglinde Weigelt-Krenz, and Mirco Scharfe
Biogeosciences, 14, 541–557, https://doi.org/10.5194/bg-14-541-2017, https://doi.org/10.5194/bg-14-541-2017, 2017
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This study focuses on how the June 2013 Elbe River flood affected the southern German Bight. The largest summer flood within the last 140 years, it generated a substantial plume of nutrient-rich, buoyant waters from the Elbe estuary onto the coast. During the calm 2013 summer, the flood was followed by prolonged (2-month) water column stratification, chlorophyll blooms in surface, and uncharacteristically low oxygen in bottom waters. With climate change, these events are becoming more frequent.
Juliane Jacob, Tina Sanders, and Kirstin Dähnke
Biogeosciences, 13, 5649–5659, https://doi.org/10.5194/bg-13-5649-2016, https://doi.org/10.5194/bg-13-5649-2016, 2016
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During a flood in the Elbe in June 2013, a unique co-occurrence of ammonium, nitrite and nitrate in the water column was found. SPM and nutrient concentrations as well as isotopes were analysed. We calculated an isotope effect 15ε of −10.0 ± 0.1 ‰ during net nitrite and 15ε of −4.0 ± 0.1 ‰ and 18ε of −5.3 ± 0.1 ‰ during net nitrate consumption. A simple box-model calculation results in combined riparian denitrification and 22 to 36 % nitrification.
Lothar Stramma, Tim Fischer, Damian S. Grundle, Gerd Krahmann, Hermann W. Bange, and Christa A. Marandino
Ocean Sci., 12, 861–873, https://doi.org/10.5194/os-12-861-2016, https://doi.org/10.5194/os-12-861-2016, 2016
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Results from a research cruise on R/V Sonne to the eastern tropical Pacific in October 2015 during the 2015–2016 El Niño show the transition of current, hydrographic, and nutrient conditions to El Niño conditions in the eastern tropical Pacific in October 2015. Although in early 2015 the El Niño was strong and in October 2015 showed a clear El Niño influence on the EUC, in the eastern tropical Pacific the measurements only showed developing El Niño water mass distributions.
Carolin R. Löscher, Hermann W. Bange, Ruth A. Schmitz, Cameron M. Callbeck, Anja Engel, Helena Hauss, Torsten Kanzow, Rainer Kiko, Gaute Lavik, Alexandra Loginova, Frank Melzner, Judith Meyer, Sven C. Neulinger, Markus Pahlow, Ulf Riebesell, Harald Schunck, Sören Thomsen, and Hannes Wagner
Biogeosciences, 13, 3585–3606, https://doi.org/10.5194/bg-13-3585-2016, https://doi.org/10.5194/bg-13-3585-2016, 2016
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The ocean loses oxygen due to climate change. Addressing this issue in tropical ocean regions (off Peru and Mauritania), we aimed to understand the effects of oxygen depletion on various aspects of marine biogeochemistry, including primary production and export production, the nitrogen cycle, greenhouse gas production, organic matter fluxes and remineralization, and the role of zooplankton and viruses.
Carolin R. Löscher, Annie Bourbonnais, Julien Dekaezemacker, Chawalit N. Charoenpong, Mark A. Altabet, Hermann W. Bange, Rena Czeschel, Chris Hoffmann, and Ruth Schmitz
Biogeosciences, 13, 2889–2899, https://doi.org/10.5194/bg-13-2889-2016, https://doi.org/10.5194/bg-13-2889-2016, 2016
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The ocean is full of eddies and they play a key role for ocean biogeochemistry. In order to understand dinitrogen (N2) fixation, one major control of oceanic primary production, we investigated three eddies in the eastern tropical South Pacific off Peru. We conducted the first detailed survey and found increased N2 fixation in the oxygen-depleted cores of anticyclonic mode water eddies. Taken together, we could – for the first time – show that eddies play an important role in N2 fixation off Peru.
Denise Müller, Hermann W. Bange, Thorsten Warneke, Tim Rixen, Moritz Müller, Aazani Mujahid, and Justus Notholt
Biogeosciences, 13, 2415–2428, https://doi.org/10.5194/bg-13-2415-2016, https://doi.org/10.5194/bg-13-2415-2016, 2016
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Estuaries act as sources of the greenhouse gases nitrous oxide (N2O) and methane (CH4) to the atmosphere. We provide first measurements of N2O and CH4 in two estuaries in north-western Borneo, a region which is dominated by peatlands. We show that N2O and CH4 concentrations in these estuaries are moderate despite high organic carbon loads, that nutrient enhancement does not lead to enhanced N2O emissions, and that the wet season dominates the variability of the emissions in these systems.
Happy Hu, Annie Bourbonnais, Jennifer Larkum, Hermann W. Bange, and Mark A. Altabet
Biogeosciences, 13, 1453–1468, https://doi.org/10.5194/bg-13-1453-2016, https://doi.org/10.5194/bg-13-1453-2016, 2016
Damian L. Arévalo-Martínez, Annette Kock, Carolin R. Löscher, Ruth A. Schmitz, Lothar Stramma, and Hermann W. Bange
Biogeosciences, 13, 1105–1118, https://doi.org/10.5194/bg-13-1105-2016, https://doi.org/10.5194/bg-13-1105-2016, 2016
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We present the first measurements of N2O across three mesoscale eddies in the eastern tropical South Pacific. Eddie's vertical structure, offshore transport, properties during its formation and near-surface primary production determined the N2O distribution. Substantial depletion of N2O within the core of anticyclonic eddies suggests that although these are transient features, N-loss processes within their centres can lead to an enhanced N2O sink which is not accounted for in marine N2O budgets.
A. Kock, D. L. Arévalo-Martínez, C. R. Löscher, and H. W. Bange
Biogeosciences, 13, 827–840, https://doi.org/10.5194/bg-13-827-2016, https://doi.org/10.5194/bg-13-827-2016, 2016
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We measured the nitrous oxide (N2O) distribution in the water column in the oxygen minimum zone off Peru, an area with extremely high N2O emissions. Our data show very variable and often very high N2O concentrations in the water column at the coast, which lead to high N2O emissions when these waters are brought to the surface. The very high N2O production off Peru may be caused by high nutrient turnover rates together with rapid changes in the oxygen concentrations.
A. R. Baker, M. Thomas, H. W. Bange, and E. Plasencia Sánchez
Biogeosciences, 13, 817–825, https://doi.org/10.5194/bg-13-817-2016, https://doi.org/10.5194/bg-13-817-2016, 2016
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Concentrations of major ions and trace metals were measured in aerosols off the coast of Peru in December 2012. A few trace metals (iron, copper, nickel, and cobalt) had anomalously high concentrations, which may be associated with industrial metal smelting activities in the region. The atmosphere appears to supply an excess of iron (relative to atmospheric nitrogen supply) to the phytoplankton community of the Peruvian upwelling system.
D. Müller, T. Warneke, T. Rixen, M. Müller, A. Mujahid, H. W. Bange, and J. Notholt
Biogeosciences, 13, 691–705, https://doi.org/10.5194/bg-13-691-2016, https://doi.org/10.5194/bg-13-691-2016, 2016
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We studied organic carbon and the dissolved greenhouse gases carbon dioxide (CO2) and carbon monoxide (CO) in two estuaries in Sarawak, Malaysia, whose coast is covered by carbon-rich peatlands. The estuaries received terrestrial organic carbon from peat-draining tributaries. A large fraction was converted to CO2 and a minor fraction to CO. Both gases were released to the atmosphere. This shows how these estuaries function as efficient filters between land and ocean in this important region.
H. E. Lutterbeck and H. W. Bange
Ocean Sci., 11, 937–946, https://doi.org/10.5194/os-11-937-2015, https://doi.org/10.5194/os-11-937-2015, 2015
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
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Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
S. T. Lennartz, A. Lehmann, J. Herrford, F. Malien, H.-P. Hansen, H. Biester, and H. W. Bange
Biogeosciences, 11, 6323–6339, https://doi.org/10.5194/bg-11-6323-2014, https://doi.org/10.5194/bg-11-6323-2014, 2014
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A time series of nine oceanic parameters from the coastal time series station Boknis Eck (BE, southwestern Baltic Sea) in the period of 1957-2013 is analysed with respect to seasonal cycles and long-term trends. Most striking was a paradoxical decreasing trend in oxygen with a simultaneous decline in eutrophication. Possible reasons for this paradox, e.g. processes related to warming temperatures such as increased decomposition of organic matter or altered ventilation, are discussed.
J. Friedrich, F. Janssen, D. Aleynik, H. W. Bange, N. Boltacheva, M. N. Çagatay, A. W. Dale, G. Etiope, Z. Erdem, M. Geraga, A. Gilli, M. T. Gomoiu, P. O. J. Hall, D. Hansson, Y. He, M. Holtappels, M. K. Kirf, M. Kononets, S. Konovalov, A. Lichtschlag, D. M. Livingstone, G. Marinaro, S. Mazlumyan, S. Naeher, R. P. North, G. Papatheodorou, O. Pfannkuche, R. Prien, G. Rehder, C. J. Schubert, T. Soltwedel, S. Sommer, H. Stahl, E. V. Stanev, A. Teaca, A. Tengberg, C. Waldmann, B. Wehrli, and F. Wenzhöfer
Biogeosciences, 11, 1215–1259, https://doi.org/10.5194/bg-11-1215-2014, https://doi.org/10.5194/bg-11-1215-2014, 2014
D. L. Arévalo-Martínez, M. Beyer, M. Krumbholz, I. Piller, A. Kock, T. Steinhoff, A. Körtzinger, and H. W. Bange
Ocean Sci., 9, 1071–1087, https://doi.org/10.5194/os-9-1071-2013, https://doi.org/10.5194/os-9-1071-2013, 2013
B. Gaye, B. Nagel, K. Dähnke, T. Rixen, N. Lahajnar, and K.-C. Emeis
Biogeosciences, 10, 7689–7702, https://doi.org/10.5194/bg-10-7689-2013, https://doi.org/10.5194/bg-10-7689-2013, 2013
L. Stramma, H. W. Bange, R. Czeschel, A. Lorenzo, and M. Frank
Biogeosciences, 10, 7293–7306, https://doi.org/10.5194/bg-10-7293-2013, https://doi.org/10.5194/bg-10-7293-2013, 2013
I.-N. Kim, K. Lee, H. W. Bange, and A. M. Macdonald
Biogeosciences, 10, 6783–6792, https://doi.org/10.5194/bg-10-6783-2013, https://doi.org/10.5194/bg-10-6783-2013, 2013
C. A. Marandino, S. Tegtmeier, K. Krüger, C. Zindler, E. L. Atlas, F. Moore, and H. W. Bange
Atmos. Chem. Phys., 13, 8427–8437, https://doi.org/10.5194/acp-13-8427-2013, https://doi.org/10.5194/acp-13-8427-2013, 2013
K. Laß, H. W. Bange, and G. Friedrichs
Biogeosciences, 10, 5325–5334, https://doi.org/10.5194/bg-10-5325-2013, https://doi.org/10.5194/bg-10-5325-2013, 2013
C. Zindler, A. Bracher, C. A. Marandino, B. Taylor, E. Torrecilla, A. Kock, and H. W. Bange
Biogeosciences, 10, 3297–3311, https://doi.org/10.5194/bg-10-3297-2013, https://doi.org/10.5194/bg-10-3297-2013, 2013
K. Dähnke and B. Thamdrup
Biogeosciences, 10, 3079–3088, https://doi.org/10.5194/bg-10-3079-2013, https://doi.org/10.5194/bg-10-3079-2013, 2013
L. M. Zamora, A. Oschlies, H. W. Bange, K. B. Huebert, J. D. Craig, A. Kock, and C. R. Löscher
Biogeosciences, 9, 5007–5022, https://doi.org/10.5194/bg-9-5007-2012, https://doi.org/10.5194/bg-9-5007-2012, 2012
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Environmental drivers constraining the seasonal variability of satellite-observed methane at Northern high latitudes
Aquatic metabolism influences temporal variations of water carbon and atmospheric carbon dioxide fluxes in a temperate salt marsh
Air temperature and precipitation constraining the modelled wetland methane emissions in a boreal region in northern Europe
Ensemble estimates of global wetland methane emissions over 2000–2020
Seasonal carbon fluxes from vegetation and soil in a Mediterranean non-tidal salt marsh
Explainable machine learning for modeling of net ecosystem exchange in boreal forests
Dynamics of CO2 and CH4 fluxes in Red Sea mangrove soils
Inferring methane emissions from African livestock by fusing drone, tower, and satellite data
Reduced microbial respiration sensitivity to soil moisture following long-term N fertilization enhances soil C retention in a boreal Scots pine forest
Nitrous oxide (N2O) in Macquarie Harbour, Tasmania
Technical note: A low-cost, automatic soil–plant–atmosphere enclosure system to investigate CO2 and evapotranspiration flux dynamics
Reviews and syntheses: Contribution of sulfate to methane oxidation in upland soils: a mini-review
Tidal influence on carbon dioxide and methane fluxes from tree stems and soils in mangrove forests
Drought conditions disrupt atmospheric carbon uptake in a Mediterranean saline lake
Physicochemical perturbation increases nitrous oxide production from denitrification in soils and sediments
Carbon degradation and mobilisation potentials of thawing permafrost peatlands in northern Norway inferred from laboratory incubations
Saturating response of photosynthesis to increasing leaf area index allows selective harvest of trees without affecting forest productivity
Seasonal dynamics and regional distribution patterns of CO2 and CH4 in the north-eastern Baltic Sea
Interannual and seasonal variability of the air–sea CO2 exchange at Utö in the coastal region of the Baltic Sea
CO2 emissions of drained coastal peatlands in the Netherlands and potential emission reduction by water infiltration systems
Influence of wind strength and direction on diffusive methane fluxes and atmospheric methane concentrations above the North Sea
Using eddy covariance observations to determine the carbon sequestration characteristics of subalpine forests in the Qinghai–Tibet Plateau
Isotopomer labeling and oxygen dependence of hybrid nitrous oxide production
The emission of CO from tropical rainforest soils
Modelling CO2 and N2O emissions from soils in silvopastoral systems of the West African Sahelian band
A case study on topsoil removal and rewetting for paludiculture: effect on biogeochemistry and greenhouse gas emissions from Typha latifolia, Typha angustifolia, and Azolla filiculoides
Assessing improvements in global ocean pCO2 machine learning reconstructions with Southern Ocean autonomous sampling
Timescale dependence of airborne fraction and underlying climate–carbon-cycle feedbacks for weak perturbations in CMIP5 models
Jacqueline K. Knutson, François Clayer, Peter Dörsch, Sebastian Westermann, and Heleen A. de Wit
Biogeosciences, 22, 3899–3914, https://doi.org/10.5194/bg-22-3899-2025, https://doi.org/10.5194/bg-22-3899-2025, 2025
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Thawing permafrost at Iškoras in northern Norway is transforming peat plateaus into thermokarst ponds and wetlands. These small ponds show striking oversaturation of dissolved greenhouse gases, such as carbon dioxide (CO2) and methane (CH4), partly owing to organic matter processing. Streams nearby emit CO2, driven by turbulence. As permafrost disappears, carbon dynamics will change, potentially increasing emissions of CH4. This study highlights the need to integrate these changes into climate models.
Laura M. van der Poel, Laurent V. Bataille, Bart Kruijt, Wietse Franssen, Wilma Jans, Jan Biermann, Anne Rietman, Alex J. V. Buzacott, Ype van der Velde, Ruben Boelens, and Ronald W. A. Hutjes
Biogeosciences, 22, 3867–3898, https://doi.org/10.5194/bg-22-3867-2025, https://doi.org/10.5194/bg-22-3867-2025, 2025
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We combine two types of carbon dioxide (CO2) data from Dutch peatlands in a machine learning model: from fixed measurement towers and from a light research aircraft. We find that emissions increase with deeper water table depths (WTDs) by 4.6 tons of CO2 per hectare per year for each 10 cm deeper WTD on average. The effect is stronger in winter than in summer and varies between locations. This variability should be taken into account when developing mitigation measures.
Thomas Bauduin, Nathalie Gypens, and Alberto V. Borges
Biogeosciences, 22, 3785–3805, https://doi.org/10.5194/bg-22-3785-2025, https://doi.org/10.5194/bg-22-3785-2025, 2025
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To investigate if greenhouse gases (GHG) emissions from ponds vary among clear-water ponds with macrophytes and turbid-water ponds with phytoplankton, we measured CO2, CH4, and N2O concentrations and emissions in two clear- and two turbid-water urban ponds in the city of Brussels from June 2021 to December 2023. Differences in CH4 ebullitive emissions were observed between clear- and turbid-water ponds but none for CO2 and N2O emissions.
Ida Bagus Mandhara Brasika, Pierre Friedlingstein, Stephen Sitch, Michael O'Sullivan, Maria Carolina Duran-Rojas, Thais Michele Rosan, Kees Klein Goldewijk, Julia Pongratz, Clemens Schwingshackl, Louise P. Chini, and George C. Hurtt
Biogeosciences, 22, 3547–3561, https://doi.org/10.5194/bg-22-3547-2025, https://doi.org/10.5194/bg-22-3547-2025, 2025
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Indonesia is the world's third-highest carbon emitter from land use change. However, there are uncertainties in the carbon emissions of Indonesia. Our best estimate of carbon emissions from land use change in Indonesia is 0.12 ± 0.02 PgC/yr with a steady trend. Despite many uncertainties created by drivers, models, and products, we also found robust agreements between these models and products. All agree that Indonesian carbon emissions from LULCC (land use and land cover change) have had no decreasing trend for the last 2 decades.
Antonio Donateo, Daniela Famulari, Donato Giovannelli, Arturo Mariani, Mauro Mazzola, Stefano Decesari, and Gianluca Pappaccogli
Biogeosciences, 22, 2889–2908, https://doi.org/10.5194/bg-22-2889-2025, https://doi.org/10.5194/bg-22-2889-2025, 2025
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This study focuses on measurements of CO2 and CH4 turbulent fluxes in tundra ecosystems in the Svalbard islands over a 2-year period. Our results reveal dynamic interactions between climatic conditions and ecosystem activities such as photosynthesis and microbial activity. In summer, photosynthesis and microbial activity increase, leading to net carbon uptake and methane consumption. Wind influences soil drying and CH4 emissions. Thermal anomalies can reduce annual carbon uptake.
Stavros Stagakis, Dominik Brunner, Junwei Li, Leif Backman, Anni Karvonen, Lionel Constantin, Leena Järvi, Minttu Havu, Jia Chen, Sophie Emberger, and Liisa Kulmala
Biogeosciences, 22, 2133–2161, https://doi.org/10.5194/bg-22-2133-2025, https://doi.org/10.5194/bg-22-2133-2025, 2025
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The balance between CO2 uptake and emissions from urban green areas is still not well understood. This study evaluated for the first time the urban park CO2 exchange simulations with four different types of biosphere model by comparing them with observations. Even though some advantages and disadvantages of the different model types were identified, there was no strong evidence that more complex models performed better than simple ones.
Chaolei Yang, Yufeng Tian, Jingqi Cui, Guangxiong He, Jingyuan Li, Canfeng Li, Haichuang Duan, Zong Wei, Liu Yan, Xin Xia, Yong Huang, Aihua Jiang, and Yuwen Feng
Biogeosciences, 22, 2097–2114, https://doi.org/10.5194/bg-22-2097-2025, https://doi.org/10.5194/bg-22-2097-2025, 2025
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Due to the influence of extreme-drought events in southwest China, the carbon sequestration capacity of the open savanna in the dry–hot valley of the Jinsha River has been significantly diminished, with soil water content being the key environmental factor governing CO2 flux. Under the climate scenario where the frequency and severity of extreme droughts are expected to continue increasing, the CO2 emissions from the open savanna are also anticipated to rise persistently.
Maren Jenrich, Juliane Wolter, Susanne Liebner, Christian Knoblauch, Guido Grosse, Fiona Giebeler, Dustin Whalen, and Jens Strauss
Biogeosciences, 22, 2069–2086, https://doi.org/10.5194/bg-22-2069-2025, https://doi.org/10.5194/bg-22-2069-2025, 2025
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Climate warming in the Arctic is causing the erosion of permafrost coasts and the transformation of permafrost lakes into lagoons. To understand how this affects greenhouse gas (GHG) emissions, we studied carbon dioxide (CO₂) and methane (CH₄) production in lagoons with varying sea connections. Younger lagoons produce more CH₄, while CO₂ increases under more marine conditions. Flooding of permafrost lowlands due to rising sea levels may lead to higher GHG emissions from Arctic coasts in future.
Amélie Pouliot, Isabelle Laurion, Antoine Thiboult, and Daniel F. Nadeau
EGUsphere, https://doi.org/10.5194/egusphere-2025-1497, https://doi.org/10.5194/egusphere-2025-1497, 2025
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Small thermokarst lakes release greenhouse gases (GHGs) as permafrost thaws, but most studies focus on diurnal measurements, potentially overlooking significant variations. We measured GHG fluxes from 2 lakes in Nunavik over twosummers—one colder, one warmer—alongside two years of continuous water column monitoring. Fluxes were higher in the warmer summer, with strong day-night differences. Our findings show that accurate GHG estimates require full diel measurements and seasonal considerations.
Tea Thum, Tuuli Miinalainen, Outi Seppälä, Holly Croft, Cheryl Rogers, Ralf Staebler, Silvia Caldararu, and Sönke Zaehle
Biogeosciences, 22, 1781–1807, https://doi.org/10.5194/bg-22-1781-2025, https://doi.org/10.5194/bg-22-1781-2025, 2025
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Climate change has the potential to influence the carbon sequestration potential of terrestrial ecosystems, and here the nitrogen cycle is also important. We used the terrestrial biosphere model QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system) in a mixed deciduous forest in Canada. We investigated the usefulness of using the leaf area index and leaf chlorophyll content to improve the parameterization of the model. This work paves the way for using spaceborne observations in model parameterizations, also including information on the nitrogen cycle.
An Truong Nguyen, Gwenaël Abril, Jacob S. Diamond, Raphaël Lamouroux, Cécile Martinet, and Florentina Moatar
EGUsphere, https://doi.org/10.5194/egusphere-2025-1478, https://doi.org/10.5194/egusphere-2025-1478, 2025
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This 32-year study of France’s Loire River shows cleaner water reduced carbon dioxide emissions by 62 %, despite increased contributions from aquatic plant activity. Seasonal emissions were higher in autumn than spring, while long-term declines were driven by reduced external carbon inputs from groundwater and soils. Results highlight how ecosystem changes influence rivers' role in global carbon cycles and climate management.
Patrick Aurich, Uwe Spank, and Matthias Koschorreck
Biogeosciences, 22, 1697–1709, https://doi.org/10.5194/bg-22-1697-2025, https://doi.org/10.5194/bg-22-1697-2025, 2025
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Lakes can be sources and sinks of the greenhouse gas carbon dioxide. The gas exchange between the atmosphere and the water can be measured by taking gas samples from them. However, the depth of water samples is not well defined, which may cause errors. We hypothesized that gradients of CO2 concentrations develop under the surface when wind speeds are very low. Our measurements show that such a gradient can occur on calm nights, potentially shifting lakes from a CO2 sink to a source.
Roxanne Daelman, Marijn Bauters, Matti Barthel, Emmanuel Bulonza, Lodewijk Lefevre, José Mbifo, Johan Six, Klaus Butterbach-Bahl, Benjamin Wolf, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 22, 1529–1542, https://doi.org/10.5194/bg-22-1529-2025, https://doi.org/10.5194/bg-22-1529-2025, 2025
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The increase in atmospheric concentrations of several greenhouse gases (GHGs) since 1750 is attributed to human activity. However, natural ecosystems, such as tropical forests, also contribute to GHG budgets. The Congo Basin hosts the second largest tropical forest and is understudied. In this study, measurements of soil GHG exchange were carried out during 16 months in a tropical forest in the Congo Basin. Overall, the soil acted as a major source of CO2 and N2O and a minor sink of CH4.
Aldis Butlers, Raija Laiho, Andis Lazdiņš, Thomas Schindler, Kaido Soosaar, Jyrki Jauhiainen, Arta Bārdule, Muhammad Kamil-Sardar, Ieva Līcīte, Valters Samariks, Andreas Haberl, Hanna Vahter, Dovilė Čiuldienė, Jani Anttila, and Kęstutis Armolaitis
EGUsphere, https://doi.org/10.5194/egusphere-2025-1032, https://doi.org/10.5194/egusphere-2025-1032, 2025
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A two-year study in Estonia, Latvia, and Lithuania evaluated the carbon balance of drained and undrained nutrient-rich forest organic soils, ranging from highly mineralized soils close to the threshold of organic soil definition to deep peat. The soils varied in pH, macronutrient levels, and C:N ratio, which contributed to the observed behavior of the soils demonstrating carbon sink and source dynamics under both drained and undrained conditions.
Olli-Pekka Tikkasalo, Olli Peltola, Pavel Alekseychik, Juha Heikkinen, Samuli Launiainen, Aleksi Lehtonen, Qian Li, Eduardo Martínez-García, Mikko Peltoniemi, Petri Salovaara, Ville Tuominen, and Raisa Mäkipää
Biogeosciences, 22, 1277–1300, https://doi.org/10.5194/bg-22-1277-2025, https://doi.org/10.5194/bg-22-1277-2025, 2025
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The emissions of greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were measured from a clear-cut peatland forest site. The measurements covered the whole year of 2022, which was the second growing season after the clear-cut. The site was a strong GHG source, and the highest emissions came from CO2, followed by N2O and CH4. A statistical model that included information on different surfaces at the site was developed to unravel surface-type-specific GHG fluxes.
Ruth Reef, Edoardo Daly, Tivanka Anandappa, Eboni-Jane Vienna-Hallam, Harriet Robertson, Matthew Peck, and Adrien Guyot
Biogeosciences, 22, 1149–1162, https://doi.org/10.5194/bg-22-1149-2025, https://doi.org/10.5194/bg-22-1149-2025, 2025
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Studies show that saltmarshes excel at capturing carbon from the atmosphere. In this study, we measured CO2 flux in an Australian temperate saltmarsh on French Island. The temperate saltmarsh exhibited strong seasonality. During the warmer growing season, the saltmarsh absorbed 10.5 g CO2 m−2 on average daily from the atmosphere. Even in winter, when plants were dormant, it continued to be a CO2 sink, albeit a smaller one. Cool temperatures and high cloud cover inhibit carbon sequestration.
Sebastian F. A. Jordan, Stefan Schloemer, Martin Krüger, Tanja Heffner, Marcus A. Horn, and Martin Blumenberg
Biogeosciences, 22, 809–830, https://doi.org/10.5194/bg-22-809-2025, https://doi.org/10.5194/bg-22-809-2025, 2025
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Using a multilayer approach, we studied the methane flux, soil gas composition, and isotopic signatures of soil methane and carbon dioxide at eight cut and buried abandoned oil wells in a peat-rich area of northern Germany. The detected methane emissions were of biogenic, peat origin and were not associated with the abandoned wells. Additional microbial analysis and methane oxidation rate measurements demonstrated a high methane emission mitigation potential in the studied peat soils.
Laura Thölix, Leif Backman, Minttu Havu, Esko Karvinen, Jesse Soininen, Justine Trémeau, Olli Nevalainen, Joyson Ahongshangbam, Leena Järvi, and Liisa Kulmala
Biogeosciences, 22, 725–749, https://doi.org/10.5194/bg-22-725-2025, https://doi.org/10.5194/bg-22-725-2025, 2025
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Cities aim for carbon neutrality and seek to understand urban vegetation's role as a carbon sink. Direct measurements are challenging, so models are used to estimate the urban carbon cycle. We evaluated model performance at estimating carbon sequestration in lawns, park trees, and urban forests in Helsinki, Finland. Models captured seasonal and annual variations well. Trees had higher sequestration rates than lawns, and irrigation often enhanced carbon sinks.
Gabrielle E. Kleber, Leonard Magerl, Alexandra V. Turchyn, Stefan Schloemer, Mark Trimmer, Yizhu Zhu, and Andrew Hodson
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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Our research on Svalbard shows that glacier melt rivers can transport large amounts of methane, a potent greenhouse gas. By studying a glacier over one summer, we found that its river was highly concentrated in methane, suggesting that rivers could provide a significant source of methane emissions as the Arctic warms and glaciers melt. This is the first time such emissions have been measured on Svalbard, indicating a wider environmental concern as such processes are occurring across the Arctic.
Martino E. Malerba, Blake Edwards, Lukas Schuster, Omosalewa Odebiri, Josh Glen, Rachel Kelly, Paul Phan, Alistair Grinham, and Peter I. Macreadie
EGUsphere, https://doi.org/10.31219/osf.io/54rd2, https://doi.org/10.31219/osf.io/54rd2, 2025
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The Pondi is a cost-effective, lightweight logger designed for long-term monitoring of carbon dioxide, methane, and nitrous oxide emissions in both terrestrial and aquatic ecosystems. It addresses key challenges in greenhouse gas monitoring by providing an automated, low-cost, solar-powered solution with cloud connectivity and real-time analytics. Its robust design enables deployment in diverse environmental conditions, supporting large-scale, high-resolution emission assessments.
Eeva Järvi-Laturi, Teemu Tahvanainen, Eero Koskinen, Efrén López-Blanco, Juho Lämsä, Hannu Marttila, Mikhail Mastepanov, Riku Paavola, Maria Väisänen, and Torben Røjle Christensen
EGUsphere, https://doi.org/10.5194/egusphere-2025-217, https://doi.org/10.5194/egusphere-2025-217, 2025
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Our research investigates how plant community composition influences methane emissions in a northern boreal rich fen. We measured methane fluxes year-round using manual chambers across 36 plots. Our findings suggest that sedges, particularly Carex rostrata, significantly impact the fluxes throughout the year. This study enhances our understanding of vegetation-driven methane emissions, providing valuable insights for predicting future changes in peatland methane emissions.
Eva-Marie Metz, Sanam Noreen Vardag, Sourish Basu, Martin Jung, and André Butz
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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We estimate CO2 fluxes in semiarid southern Africa from 2009 to 2018 based on satellite CO2 measurements and atmospheric inverse modeling. By selecting process-based vegetation models, which agree with the satellite CO2 fluxes, we find that soil respiration mainly drives the seasonality, whereas photosynthesis substantially influences the interannual variability. Our study emphasizes the need for better representation of the response of semiarid ecosystems to soil rewetting in vegetation models.
Ella Kivimäki, Tuula Aalto, Michael Buchwitz, Kari Luojus, Jouni Pulliainen, Kimmo Rautiainen, Oliver Schneising, Anu-Maija Sundström, Johanna Tamminen, Aki Tsuruta, and Hannakaisa Lindqvist
EGUsphere, https://doi.org/10.5194/egusphere-2025-249, https://doi.org/10.5194/egusphere-2025-249, 2025
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We investigate how environmental variables influencing natural methane fluxes explain the large-scale seasonal variability of satellite-observed methane at Northern high latitudes. Our findings show that soil moisture, snow cover, and soil temperature have the strongest influence, with snowmelt playing a surprisingly significant role, likely through soil isolation and wetting. This study highlights the value of multi-satellite observations for understanding large-scale wetland emissions.
Jérémy Mayen, Pierre Polsenaere, Aurore Regaudie de Gioux, Jonathan Deborde, Karine Collin, Yoann Le Merrer, Élodie Foucault, Vincent Ouisse, Laurent André, Marie Arnaud, Pierre Kostyrka, Éric Lamaud, Gwenaël Abril, and Philippe Souchu
EGUsphere, https://doi.org/10.5194/egusphere-2025-335, https://doi.org/10.5194/egusphere-2025-335, 2025
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In a salt marsh, we performed seasonal 24-h cycles to look for aquatic metabolism influence on water carbon dynamics and net ecosystem CO2 exchanges (NEE). From high to low tide in winter, marsh anaerobic respiration induced the highest levels of dissolved inorganic carbon and alkalinity. On the contrary, in spring and summer, marsh primary production led to CO2-depleted water exportations downstream. Aquatic heterotrophy at high tide can influence NEE during the highest immersion levels only.
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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Wetland methane responses to temperature and precipitation were studied in a boreal wetland-rich region in northern Europe using ecosystem models, atmospheric inversions, and upscaled flux observations. The ecosystem models differed in their responses to temperature and precipitation and in their seasonality. However, multi-model means, inversions, and upscaled fluxes had similar seasonality, and they suggested co-limitation by temperature and precipitation.
Zhen Zhang, Benjamin Poulter, Joe R. Melton, William J. Riley, George H. Allen, David J. Beerling, Philippe Bousquet, Josep G. Canadell, Etienne Fluet-Chouinard, Philippe Ciais, Nicola Gedney, Peter O. Hopcroft, Akihiko Ito, Robert B. Jackson, Atul K. Jain, Katherine Jensen, Fortunat Joos, Thomas Kleinen, Sara H. Knox, Tingting Li, Xin Li, Xiangyu Liu, Kyle McDonald, Gavin McNicol, Paul A. Miller, Jurek Müller, Prabir K. Patra, Changhui Peng, Shushi Peng, Zhangcai Qin, Ryan M. Riggs, Marielle Saunois, Qing Sun, Hanqin Tian, Xiaoming Xu, Yuanzhi Yao, Yi Xi, Wenxin Zhang, Qing Zhu, Qiuan Zhu, and Qianlai Zhuang
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.
Alouette van Hove, Kristoffer Aalstad, Vibeke Lind, Claudia Arndt, Vincent Odongo, Rodolfo Ceriani, Francesco Fava, John Hulth, and Norbert Pirk
EGUsphere, https://doi.org/10.5194/egusphere-2024-3994, https://doi.org/10.5194/egusphere-2024-3994, 2025
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Research on methane emissions from African livestock is limited. We used a probabilistic method fusing drone and flux tower observations with an atmospheric model to estimate emissions from various herds. This approach proved robust under non-stationary wind conditions and effective in estimating emissions as low as 100 g h-1. We also detected herd locations using spectral anomalies in satellite data. Our approach can be used to estimate diverse sources, thereby improving emission inventories.
Boris Ťupek, Aleksi Lehtonen, Stefano Manzoni, Elisa Bruni, Petr Baldrian, Etienne Richy, Bartosz Adamczyk, Bertrand Guenet, and Raisa Mäkipää
EGUsphere, https://doi.org/10.5194/egusphere-2024-3813, https://doi.org/10.5194/egusphere-2024-3813, 2024
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We explored soil microbial respiration (Rh) kinetics of low-dose and long-term N fertilization in N-limited boreal forest in connection to CH₄, and N₂O fluxes, soil, and tree C sinks. The insights show that N fertilization effects C retention in boreal forest soils through modifying Rh sensitivities to soil temperature and moisture. The key findings reveal that N-enriched soils exhibited reduced sensitivity of Rh to moisture, which on annual level contributes to enhanced soil C sequestration.
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.
Rui Su, Kexin Li, Nannan Wang, Fenghui Yuan, Ying Zhao, Yunjiang Zuo, Ying Sun, Liyuan He, Xiaofeng Xu, and Lihua Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2024-3347, https://doi.org/10.5194/egusphere-2024-3347, 2024
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This research examines the effect of sulfate on methane oxidation in soil, finding that sulfate may facilitate methane oxidation. Considering methane's role as a greenhouse gas and rising sulfate deposition, the study aims to predict changes in methane oxidation due to acid deposition. Future experiments will explore microbial mechanisms, as sulfate reduces methane emissions while enhancing its consumption, providing insights for mitigation strategies.
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.
Olivier Bouriaud, Ernst-Detlef Schulze, Konstantin Gregor, Issam Bourkhris, Peter Högberg, Roland Irslinger, Phillip Papastefanou, Julia Pongratz, Anja Rammig, Riccardo Valentini, and Christian Körner
EGUsphere, https://doi.org/10.5194/egusphere-2024-3092, https://doi.org/10.5194/egusphere-2024-3092, 2024
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The impact of harvesting on forests' carbon sink capacities is debated. One view is that their sink strength is resilient to harvesting, the other that it disrupts these capacities. Our work shows that leaf area index (LAI) has been overlooked in this discussion. We found that temperate forests' carbon uptake is largely insensitive to variations in LAI beyond about 4 m² m-², but that forests operate at higher levels.
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.
Colette L. Kelly, Nicole M. Travis, Pascale Anabelle Baya, Claudia Frey, Xin Sun, Bess B. Ward, and Karen L. Casciotti
Biogeosciences, 21, 3215–3238, https://doi.org/10.5194/bg-21-3215-2024, https://doi.org/10.5194/bg-21-3215-2024, 2024
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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.
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.
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.
Cited articles
Amann, T., Weiss, A., and Hartmann, J.:
Carbon dynamics in the freshwater part of the Elbe estuary, Germany: Implications of improving water quality, Estuar. Coast. Shelf S., 107, 112–121, https://doi.org/10.1016/j.ecss.2012.05.012, 2012.
Bange, H. W.:
Nitrous oxide and methane in European coastal waters, Estuar. Coast. Shelf S., 70, 361–374, https://doi.org/10.1016/j.ecss.2006.05.042, 2006.
Bange, H. W.:
Gaseous Nitrogen Compounds (NO, N2O, N2, NH3) in the Ocean, Chap. 2, in: Nitrogen in the Marine Environment, 2nd Edn., edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and Carpenter, E. J., https://doi.org/10.1016/B978-0-12-372522-6.00002-5, 51–94, ISBN 9780123725226, 2008.
Barnes, J. and Owens, N. J. P.:
Denitrification and Nitrous Oxide Concentrations in the Humber Estuary, UK, and Adjacent Coastal Zones, Mar. Pollut. Bull., 37, 247–260, https://doi.org/10.1016/S0025-326X(99)00079-X, 1999.
Barnes, J. and Upstill-Goddard, R. C.:
N2O seasonal distributions and air–sea exchange in UK estuaries: Implications for the tropospheric N2O source from European coastal waters, J. Geophys. Res.-Biogeo., 116, G01006, https://doi.org/10.1029/2009JG001156, 2011.
Barnes, J., Ramesh, R., Purvaja, R., Nirmal Rajkumar, A., Senthil Kumar, B., Krithika, K., Ravichandran, K., Uher, G., and Upstill-Goddard, R.:
Tidal dynamics and rainfall control N2O and CH4 emissions from a pristine mangrove creek, Geophys. Res. Lett., 33, L15405, https://doi.org/10.1029/2006GL026829, 2006.
Baulch, H. M., Dillon, P. J., Maranger, R., Venkiteswaran, J. J., Wilson, H. F., and Schiff, S. L.:
Night and day: short-term variation in nitrogen chemistry and nitrous oxide emissions from streams, Freshwater Biol., 57, 509–525, https://doi.org/10.1111/j.1365-2427.2011.02720.x, 2012.
Beaulieu, J. J., Shuster, W. D., and Rebholz, J. A.:
Nitrous Oxide Emissions from a Large, Impounded River: The Ohio River, Environ. Sci. Technol., 44, 7527–7533, https://doi.org/10.1021/es1016735, 2010.
Bergemann, M.:
Die Trübungszone in der Tideelbe – Beschreibung der räumlichen und zeitlichen Entwicklung, Wassergütestelle Elbe, https://www.fgg-elbe.de/files/Download-Archive/Fachberichte/Truebungsverhaeltnisse/04Truebungsz.pdf (last access: 27 July 2023), 2004.
Bergemann, M. and Gaumert, T.:
Elbebericht 2008: Ergebnisse des nationalen Überwachungsprogramms Elbe der Bundesländerüber den ökologischen und chemischen Zustand der Elbe nach EG-WRRLsowie der Trendentwicklung von Stoffen und Schadstoffgruppen, Flussgebietsgemeinschaft Elbe (FGG Elbe), Hamburg, https://www.fgg-elbe.de/berichte/aktualisierung-nach-art-13-2021.html?file=files/Downloads/EG_WRRL/ber/bp2021/Bewirtschaftungsplan_FGG_Elbe_2021.pdf&cid=14864
(last access: 27 July 2023), 2008.
Bianchi, T. S.:
Biogeochemistry of Estuaries, Oxford University Press, New York, 706 pp., https://doi.org/10.1093/oso/9780195160826.001.0001, 2007.
Boehlich, M. J. and Strotmann, T.:
The Elbe Estuary, Küste, 74, 288–306, 2008.
Boehlich, M. J. and Strotmann, T.:
Das Elbeästuar, Küste, 87, Kuratorium für Forschung im Küsteningenieurwesen (KFKI), https://doi.org/10.18171/1.087106, 2019.
Borges, A., Vanderborght, J.-P., Schiettecatte, L.-S., Gazeau, F., Ferrón-Smith, S., Delille, B., and Frankignoulle, M.:
Variability of gas transfer velocity of CO2 in a macrotidal estuary (The Scheldt), Estuaries, 27, 593–603, https://doi.org/10.1007/BF02907647, 2004.
Borges, A. V., Darchambeau, F., Teodoru, C. R., Marwick, T. R., Tamooh, F., Geeraert, N., Omengo, F. O., Guérin, F., Lambert, T., Morana, C., Okuku, E., and Bouillon, S.:
Globally significant greenhouse-gas emissions from African inland waters, Nat. Geosci., 8, 637–642, https://doi.org/10.1038/ngeo2486, 2015.
Bouwman, A. F., Bierkens, M. F. P., Griffioen, J., Hefting, M. M., Middelburg, J. J., Middelkoop, H., and Slomp, C. P.:
Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models, Biogeosciences, 10, 1–22, https://doi.org/10.5194/bg-10-1-2013, 2013.
Brase, L., Bange, H. W., Lendt, R., Sanders, T., and Dähnke, K.:
High Resolution Measurements of Nitrous Oxide (N2O) in the Elbe Estuary, Front. Mar. Sci., 4, 162, https://doi.org/10.3389/fmars.2017.00162, 2017a.
Brase, L., Bange, H. W., Lendt, R., Sanders, T., and Dähnke, K.: Nitrous oxide (N2O) measurements in the surface water of the Elbe Estuary in 2015, PANGAEA [data set], https://doi.org/10.1594/PANGAEA.882348, 2017b.
Brown, A. M., Bass, A. M., and Pickard, A. E.:
Anthropogenic-estuarine interactions cause disproportionate greenhouse gas production: A review of the evidence base, Mar. Pollut. Bull., 174, 113240, https://doi.org/10.1016/j.marpolbul.2021.113240, 2022.
Büttner, O., Jawitz, J. W., and Borchardt, D.:
Ecological status of river networks: stream order-dependent impacts of agricultural and urban pressures across ecoregions, Environ. Res. Lett., 15, 1040b3, https://doi.org/10.1088/1748-9326/abb62e, 2020.
Chun, Y., Kim, D., Hattori, S., Toyoda, S., Yoshida, N., Huh, J., Lim, J.-H., and Park, J.-H.:
Temperature control on wastewater and downstream nitrous oxide emissions in an urbanized river system, Water Res., 187, 116417, https://doi.org/10.1016/j.watres.2020.116417, 2020.
Clark, J. F., Schlosser, P., Simpson, H. J., Stute, M., Wanninkhof, R., and Ho, D. T.:
Relationship between gas transfer velocities and wind speeds in the tidal Hudson River determined by the dual tracer technique, in: Air–Water Gas Transfer, edited by: Jähne, B. and Monahan, E. C., AEON Verlag, Hanau, 785–800, http://www.soest.hawaii.edu/oceanography/faculty/ho/papers/Relationship_between_Gas_Transfer_Velocities_and_W.pdf (last access: 27 July 2023), 1995.
Crossland, C. J., Baird, D., Ducrotoy, J.-P., Lindeboom, H., Buddemeier, R. W., Dennison, W. C., Maxwell, B. A., Smith, S. V., and Swaney, D. P.:
The Coastal Zone – a Domain of Global Interactions, in: Coastal Fluxes in the Anthropocene: The Land-Ocean Interactions in the Coastal Zone Project of the International Geosphere-Biosphere Programme, edited by: Crossland, C. J., Kremer, H. H., Lindeboom, H. J., Marshall Crossland, J. I., and Tissier, M. D. A., Springer, Berlin, Heidelberg, https://doi.org/10.1007/3-540-27851-6_1, 1–37, 2005.
Dähnke, K., Bahlmann, E., and Emeis, K.-C.:
A nitrate sink in estuaries? An assessment by means of stable nitrate isotopes in the Elbe estuary, Limnol. Oceanogr., 53, 1504–1511, https://doi.org/10.4319/lo.2008.53.4.1504, 2008.
Dähnke, K., Sanders, T., Voynova, Y., and Wankel, S. D.:
Nitrogen isotopes reveal a particulate-matter-driven biogeochemical reactor in a temperate estuary, Biogeosciences, 19, 5879–5891, https://doi.org/10.5194/bg-19-5879-2022, 2022.
de Bie, M. J. M., Middelburg, J. J., Starink, M., and Laanbroek, H. J.:
Factors controlling nitrous oxide at the microbial community and estuarine scale, Mar. Ecol.-Prog. Ser., 240, 1–9, https://doi.org/10.3354/meps240001, 2002.
de Wilde, H. P. and de Bie, M. J.:
Nitrous oxide in the Schelde estuary: production by nitrification and emission to the atmosphere, Mar. Chem., 69, 203–216, https://doi.org/10.1016/S0304-4203(99)00106-1, 2000.
Deek, A., Dähnke, K., van Beusekom, J., Meyer, S., Voss, M., and Emeis, K.-C.:
N2 fluxes in sediments of the Elbe Estuary and adjacent coastal zones, Mar. Ecol.-Prog. Ser., 493, 9–21, https://doi.org/10.3354/meps10514, 2013.
Dijkstra, Y. M., Chant, R. J., and Reinfelder, J. R.:
Factors Controlling Seasonal Phytoplankton Dynamics in the Delaware River Estuary: an Idealized Model Study, Estuaries Coasts, 42, 1839–1857, https://doi.org/10.1007/s12237-019-00612-3, 2019.
Fabisik, F., Guieysse, B., Procter, J., and Plouviez, M.:
Nitrous oxide (N2O) synthesis by the freshwater cyanobacterium Microcystis aeruginosa, Biogeosciences, 20, 687–693, https://doi.org/10.5194/bg-20-687-2023, 2023.
FGG Elbe:
Nährstoffminderungsstrategie für die Flussgebietsgemeinschaft Elbe, Flussgebietsgemeinschaft Elbe (FGG Elbe), Magdeburg, https://www.fgg-elbe.de/files/Downloads/News/Projekte/Naehrstoffminderungsstrategie_2018_12-04.pdf
(last access: 27 July 2023), 2018.
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(last access: 21 November 2022), 2022.
Fraga, F., Ríos, A. F., Pérez, F. F., and Figueiras, F. G.:
Theoretical limits of oxygen:carbon and oxygen:nitrogen ratios during photosynthesis and mineralisation of organic matter in the sea, Sci. Mar., 62, 161–168, https://doi.org/10.3989/scimar.1998.62n1-2161, 1998.
Garnier, J., Cébron, A., Tallec, G., Billen, G., Sebilo, M., and Martinez, A.:
Nitrogen Behaviour and Nitrous Oxide Emission in the Tidal Seine River Estuary (France) as Influenced by Human Activities in the Upstream Watershed, Biogeochemistry, 77, 305–326, https://doi.org/10.1007/s10533-005-0544-4, 2006.
Gaumert, T. and Bergemann, M.:
Sauerstoffgehalt der Tideelbe – Entwicklung der kritischen Sauerstoffgehalte im Jahr 2007 und in den Vorjahren, Erörterung möglicher Ursachen und Handlungsoptionen, Flussgebietsgemeinschaft Elbe, https://www.fgg-elbe.de/files/Download-Archive/Fachberichte/Sauerstoffhaushalt/FGG_Elbe-O2-Haushalt.pdf
(last access: 27 July 2023), 2007.
Geerts, L., Wolfstein, K., Jacobs, S., van Damme, S., and Vandenbruwaene, W.:
Zonation of the TIDE estuaries, TIDE toolbox, https://www.tide-toolbox.eu/pdf/reports/Zonation_of_the_TIDE_estuaries.pdf
(last access: 27 July 2023),
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Gonçalves, C., Brogueira, M. J., and Camões, M. F.:
Seasonal and tidal influence on the variability of nitrous oxide in the Tagus estuary, Portugal, Sci. Mar., 74, 57–66, https://doi.org/10.3989/scimar.2010.74s1057, 2010.
Gonçalves, C., Brogueira, M. J., and Nogueira, M.:
Tidal and spatial variability of nitrous oxide (N2O) in Sado estuary (Portugal), Estuar. Coast. Shelf S., 167, 466–474, https://doi.org/10.1016/j.ecss.2015.10.028, 2015.
Hall Jr., R. O. and Ulseth, A. J.:
Gas exchange in streams and rivers, WIREs Water, 7, e1391, https://doi.org/10.1002/wat2.1391, 2020.
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Hanke, V.-R. and Knauth, H.-D.:
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Hansen, H. P. and Koroleff, F.:
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Harley, J. F., Carvalho, L., Dudley, B., Heal, K. V., Rees, R. M., and Skiba, U.:
Spatial and seasonal fluxes of the greenhouse gases N2O, CO2 and CH4 in a UK macrotidal estuary, Estuar. Coast. Shelf S., 153, 62–73, https://doi.org/10.1016/j.ecss.2014.12.004, 2015.
Hedges, J. I. and Keil, R. G.:
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Hein, S. S. V., Sohrt, V., Nehlsen, E., Strotmann, T., and Fröhle, P.:
Tidal Oscillation and Resonance in Semi-Closed Estuaries—Empirical Analyses from the Elbe Estuary, North Sea, Water, 13, 848, https://doi.org/10.3390/w13060848, 2021.
Hillebrand, G., Hardenbicker, P., Fischer, H., Otto, W., and Vollmer, S.:
Dynamics of total suspended matter and phytoplankton loads in the river Elbe, J. Soils Sediments, 18, 3104–3113, https://doi.org/10.1007/s11368-018-1943-1, 2018.
Hofmann, J., Behrendt, H., Gilbert, A., Janssen, R., Kannen, A., Kappenberg, J., Lenhart, H., Lise, W., Nunneri, C., and Windhorst, W.:
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HPA and Freie und Hansestadt Hamburg:
Deutsches Gewässerkundliches Jahrbuch – Elbegebiet, Teil III, Untere Elbe ab der Havelmündung – 2014, Hamburg, 2017.
Hu, M., Chen, D., and Dahlgren, R. A.:
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Short summary
Nitrous oxide (N2O) is an important greenhouse gas. However, N2O emissions from estuaries underlie significant uncertainties due to limited data availability and high spatiotemporal variability. We found the Elbe Estuary (Germany) to be a year-round source of N2O, with the highest emissions in winter along with high nitrogen loads. However, in spring and summer, N2O emissions did not decrease alongside lower nitrogen loads because organic matter fueled in situ N2O production along the estuary.
Nitrous oxide (N2O) is an important greenhouse gas. However, N2O emissions from estuaries...
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