Articles | Volume 19, issue 24
https://doi.org/10.5194/bg-19-5879-2022
© Author(s) 2022. 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-19-5879-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
21 Dec 2022
Research article |
| 21 Dec 2022
| 21 Dec 2022
Nitrogen isotopes reveal a particulate-matter-driven biogeochemical reactor in a temperate estuary
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Tina Sanders
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Yoana Voynova
Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Scott D. Wankel
Woods Hole Oceanographic Institution, Woods Hole,
MA 02543, USA
Related authors
Andreas Neumann, Justus E. E. van Beusekom, Alexander Bratek, Jana Friedrich, Jürgen Möbius, Tina Sanders, Hendrik Wolschke, and Kirstin Dähnke
EGUsphere, https://doi.org/10.5194/egusphere-2025-1803, https://doi.org/10.5194/egusphere-2025-1803, 2025
Short summary
Short summary
The North-Western shelf of the Black Sea is substantially influenced by the discharge of nutrients from River Danube. We have sampled the sediment there and measured particulate carbon and nitrogen to reconstruct the variability of nitrogen sources to the NW shelf. Our results demonstrate that the balance of riverine nitrogen input and marine nitrogen fixation is sensitive to climate changes. Nitrogen from human activities is detectable in NW shelf sediment since the 12th century.
Gesa Schulz, Kirstin Dähnke, Tina Sanders, Jan Penopp, Hermann W. Bange, Rena Czeschel, and Birgit Gaye
EGUsphere, https://doi.org/10.5194/egusphere-2025-1660, https://doi.org/10.5194/egusphere-2025-1660, 2025
Short summary
Short summary
Oxygen minimum zones (OMZs) are low-oxygen ocean areas that deplete nitrogen, a key marine nutrient. Understanding nitrogen cycling in OMZs is crucial for the global nitrogen cycle. This study examined nitrogen cycling in the OMZ of the Bay of Bengal and East Equatorial Indian Ocean, revealing limited mixing between both regions. Surface phytoplankton consumes nitrate, while deeper nitrification recycles nitrogen. In the BoB’s OMZ (100–300 m), nitrogen loss likely occurs via anammox.
Mona Norbisrath, Andreas Neumann, Kirstin Dähnke, Tina Sanders, Andreas Schöl, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 20, 4307–4321, https://doi.org/10.5194/bg-20-4307-2023, https://doi.org/10.5194/bg-20-4307-2023, 2023
Short summary
Short summary
Total alkalinity (TA) is the oceanic capacity to store CO2. Estuaries can be a TA source. Anaerobic metabolic pathways like denitrification (reduction of NO3− to N2) generate TA and are a major nitrogen (N) sink. Another important N sink is anammox that transforms NH4+ with NO2− into N2 without TA generation. By combining TA and N2 production, we identified a TA source, denitrification, occurring in the water column and suggest anammox as the dominant N2 producer in the bottom layer of the Ems.
Gesa Schulz, Tina Sanders, Yoana G. Voynova, Hermann W. Bange, and Kirstin Dähnke
Biogeosciences, 20, 3229–3247, https://doi.org/10.5194/bg-20-3229-2023, https://doi.org/10.5194/bg-20-3229-2023, 2023
Short summary
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.
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
Short summary
Short summary
Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
Biogeosciences, 19, 2397–2415, https://doi.org/10.5194/bg-19-2397-2022, https://doi.org/10.5194/bg-19-2397-2022, 2022
Short summary
Short summary
We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
Short summary
Short summary
Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
Alexander Bratek, Justus E. E. van
Beusekom, Andreas Neumann, Tina Sanders, Jana Friedrich, Kay-Christian Emeis, and Kirstin Dähnke
Biogeosciences, 17, 2839–2851, https://doi.org/10.5194/bg-17-2839-2020, https://doi.org/10.5194/bg-17-2839-2020, 2020
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
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
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
Vlad A. Macovei, Louise C. V. Rewrie, Rüdiger Röttgers, and Yoana G. Voynova
Biogeosciences, 22, 3375–3396, https://doi.org/10.5194/bg-22-3375-2025, https://doi.org/10.5194/bg-22-3375-2025, 2025
Short summary
Short summary
We found that biogeochemical variability at the land–sea interface (LSI) in two major temperate estuaries is modulated by the 14 d spring–neap tidal cycle, with large effects on dissolved inorganic and organic carbon concentrations and distribution. As this effect increases the strength of the carbon source to the atmosphere by up to 74 % during spring tide, it should be accounted for in regional models, which aim to resolve biogeochemical processing at the LSI.
Andreas Neumann, Justus E. E. van Beusekom, Alexander Bratek, Jana Friedrich, Jürgen Möbius, Tina Sanders, Hendrik Wolschke, and Kirstin Dähnke
EGUsphere, https://doi.org/10.5194/egusphere-2025-1803, https://doi.org/10.5194/egusphere-2025-1803, 2025
Short summary
Short summary
The North-Western shelf of the Black Sea is substantially influenced by the discharge of nutrients from River Danube. We have sampled the sediment there and measured particulate carbon and nitrogen to reconstruct the variability of nitrogen sources to the NW shelf. Our results demonstrate that the balance of riverine nitrogen input and marine nitrogen fixation is sensitive to climate changes. Nitrogen from human activities is detectable in NW shelf sediment since the 12th century.
Gesa Schulz, Kirstin Dähnke, Tina Sanders, Jan Penopp, Hermann W. Bange, Rena Czeschel, and Birgit Gaye
EGUsphere, https://doi.org/10.5194/egusphere-2025-1660, https://doi.org/10.5194/egusphere-2025-1660, 2025
Short summary
Short summary
Oxygen minimum zones (OMZs) are low-oxygen ocean areas that deplete nitrogen, a key marine nutrient. Understanding nitrogen cycling in OMZs is crucial for the global nitrogen cycle. This study examined nitrogen cycling in the OMZ of the Bay of Bengal and East Equatorial Indian Ocean, revealing limited mixing between both regions. Surface phytoplankton consumes nitrate, while deeper nitrification recycles nitrogen. In the BoB’s OMZ (100–300 m), nitrogen loss likely occurs via anammox.
Bennet Juhls, Anne Morgenstern, Jens Hölemann, Antje Eulenburg, Birgit Heim, Frederieke Miesner, Hendrik Grotheer, Gesine Mollenhauer, Hanno Meyer, Ephraim Erkens, Felica Yara Gehde, Sofia Antonova, Sergey Chalov, Maria Tereshina, Oxana Erina, Evgeniya Fingert, Ekaterina Abramova, Tina Sanders, Liudmila Lebedeva, Nikolai Torgovkin, Georgii Maksimov, Vasily Povazhnyi, Rafael Gonçalves-Araujo, Urban Wünsch, Antonina Chetverova, Sophie Opfergelt, and Pier Paul Overduin
Earth Syst. Sci. Data, 17, 1–28, https://doi.org/10.5194/essd-17-1-2025, https://doi.org/10.5194/essd-17-1-2025, 2025
Short summary
Short summary
The Siberian Arctic is warming fast: permafrost is thawing, river chemistry is changing, and coastal ecosystems are affected. We aimed to understand changes in the Lena River, a major Arctic river flowing to the Arctic Ocean, by collecting 4.5 years of detailed water data, including temperature and carbon and nutrient contents. This dataset records current conditions and helps us to detect future changes. Explore it at https://doi.org/10.1594/PANGAEA.913197 and https://lena-monitoring.awi.de/.
Julia Meyer, Yoana G. Voynova, Bryce Van Dam, Lara Luitjens, Dagmar Daehne, and Helmuth Thomas
EGUsphere, https://doi.org/10.5194/egusphere-2024-3048, https://doi.org/10.5194/egusphere-2024-3048, 2024
Short summary
Short summary
The study highlights the inter-seasonal variability of the carbonate dynamics of the East Frisian Wadden Sea, the world's largest intertidal area. During spring, increased biological activity leads to lower CO2 and nitrate levels, while total alkalinity (TA) rises slightly. In summer, TA increases, enhancing the ocean's ability to absorb CO2. Our research emphasizes the vital role of these intertidal regions in regulating carbon, contributing to a better understanding of carbon storage.
Louise C. V. Rewrie, Burkard Baschek, Justus E. E. van Beusekom, Arne Körtzinger, Gregor Ollesch, and Yoana G. Voynova
Biogeosciences, 20, 4931–4947, https://doi.org/10.5194/bg-20-4931-2023, https://doi.org/10.5194/bg-20-4931-2023, 2023
Short summary
Short summary
After heavy pollution in the 1980s, a long-term inorganic carbon increase in the Elbe Estuary (1997–2020) was fueled by phytoplankton and organic carbon production in the upper estuary, associated with improved water quality. A recent drought (2014–2020) modulated the trend, extending the water residence time and the dry summer season into May. The drought enhanced production of inorganic carbon in the estuary but significantly decreased the annual inorganic carbon export to coastal waters.
Mona Norbisrath, Andreas Neumann, Kirstin Dähnke, Tina Sanders, Andreas Schöl, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 20, 4307–4321, https://doi.org/10.5194/bg-20-4307-2023, https://doi.org/10.5194/bg-20-4307-2023, 2023
Short summary
Short summary
Total alkalinity (TA) is the oceanic capacity to store CO2. Estuaries can be a TA source. Anaerobic metabolic pathways like denitrification (reduction of NO3− to N2) generate TA and are a major nitrogen (N) sink. Another important N sink is anammox that transforms NH4+ with NO2− into N2 without TA generation. By combining TA and N2 production, we identified a TA source, denitrification, occurring in the water column and suggest anammox as the dominant N2 producer in the bottom layer of the Ems.
Gesa Schulz, Tina Sanders, Yoana G. Voynova, Hermann W. Bange, and Kirstin Dähnke
Biogeosciences, 20, 3229–3247, https://doi.org/10.5194/bg-20-3229-2023, https://doi.org/10.5194/bg-20-3229-2023, 2023
Short summary
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.
Olga Ogneva, Gesine Mollenhauer, Bennet Juhls, Tina Sanders, Juri Palmtag, Matthias Fuchs, Hendrik Grotheer, Paul J. Mann, and Jens Strauss
Biogeosciences, 20, 1423–1441, https://doi.org/10.5194/bg-20-1423-2023, https://doi.org/10.5194/bg-20-1423-2023, 2023
Short summary
Short summary
Arctic warming accelerates permafrost thaw and release of terrestrial organic matter (OM) via rivers to the Arctic Ocean. We compared particulate organic carbon (POC), total suspended matter, and C isotopes (δ13C and Δ14C of POC) in the Lena delta and Lena River along a ~1600 km transect. We show that the Lena delta, as an interface between the Lena River and the Arctic Ocean, plays a crucial role in determining the qualitative and quantitative composition of OM discharged into the Arctic Ocean.
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
Short summary
Short summary
Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Matthias Fuchs, Juri Palmtag, Bennet Juhls, Pier Paul Overduin, Guido Grosse, Ahmed Abdelwahab, Michael Bedington, Tina Sanders, Olga Ogneva, Irina V. Fedorova, Nikita S. Zimov, Paul J. Mann, and Jens Strauss
Earth Syst. Sci. Data, 14, 2279–2301, https://doi.org/10.5194/essd-14-2279-2022, https://doi.org/10.5194/essd-14-2279-2022, 2022
Short summary
Short summary
We created digital, high-resolution bathymetry data sets for the Lena Delta and Kolyma Gulf regions in northeastern Siberia. Based on nautical charts, we digitized depth points and isobath lines, which serve as an input for a 50 m bathymetry model. The benefit of this data set is the accurate mapping of near-shore areas as well as the offshore continuation of the main deep river channels. This will improve the estimation of river outflow and the nutrient flux output into the coastal zone.
Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
Biogeosciences, 19, 2397–2415, https://doi.org/10.5194/bg-19-2397-2022, https://doi.org/10.5194/bg-19-2397-2022, 2022
Short summary
Short summary
We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
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
Short summary
Short summary
Buried animal and plant remains (carbon) from the last ice age were freeze-locked in permafrost. At an extremely fast eroding permafrost cliff in the Lena Delta (Siberia), we found this formerly frozen carbon well preserved. Our results show that ongoing degradation releases substantial amounts of this carbon, making it available for future carbon emissions. This mobilisation at the studied cliff and also similarly eroding sites bear the potential to affect rivers and oceans negatively.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
Short summary
Short summary
Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
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
Short summary
Short summary
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.
Anna-Neva Visser, Scott D. Wankel, Pascal A. Niklaus, James M. Byrne, Andreas A. Kappler, and Moritz F. Lehmann
Biogeosciences, 17, 4355–4374, https://doi.org/10.5194/bg-17-4355-2020, https://doi.org/10.5194/bg-17-4355-2020, 2020
Short summary
Short summary
This study focuses on the chemical reaction between Fe(II) and nitrite, which has been reported to produce high levels of the greenhouse gas N2O. We investigated the extent to which dead biomass and Fe(II) minerals might enhance this reaction. Here, nitrite reduction was highest when both additives were present but less pronounced if only Fe(II) minerals were added. Both reaction systems show distinct differences, rather low N2O levels, and indicated the abiotic production of N2.
Alexander Bratek, Justus E. E. van
Beusekom, Andreas Neumann, Tina Sanders, Jana Friedrich, Kay-Christian Emeis, and Kirstin Dähnke
Biogeosciences, 17, 2839–2851, https://doi.org/10.5194/bg-17-2839-2020, https://doi.org/10.5194/bg-17-2839-2020, 2020
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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.
S. D. Wankel, C. Buchwald, W. Ziebis, C. B. Wenk, and M. F. Lehmann
Biogeosciences, 12, 7483–7502, https://doi.org/10.5194/bg-12-7483-2015, https://doi.org/10.5194/bg-12-7483-2015, 2015
Short summary
Short summary
In the sediments underlying the global oligotrophic ocean, low levels of microbial activity persist, despite low input of organic matter from surface ocean productivity. Using measured nitrogen and oxygen isotopes of porewater nitrate we estimate the magnitude and extent of microbial nitrogen cycling. We find evidence for the overlap of both denitrification as well as autotrophic pathways such as nitrification and nitrogen fixation, pointing to a relatively large role for subsurface autotrophy.
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
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
Related subject area
Biogeochemistry: Rivers & Streams
Responses of riverine dissolved organic matter to damming in two distinct hydrological regimes in northern Spain
Temporal dynamics and environmental controls of carbon dioxide and methane fluxes measured by the eddy covariance method over a boreal river
Water Column Respiration in the Yakima River Basin is Explained by Temperature, Nutrients and Suspended Solids
Shifts in organic matter character and microbial assemblages from glacial headwaters to downstream reaches in the Canadian Rocky Mountains
Molecular-level characterization of supraglacial dissolved and water-extractable organic matter along a hydrological flow path in a Greenland Ice Sheet micro-catchment
Seasonal and spatial pattern of dissolved organic matter biodegradation and photodegradation in boreal humic waters
The role of nitrogen and iron biogeochemical cycles in the production and export of dissolved organic matter in agricultural headwater catchments
From Iron Curtain to green belt: shift from heterotrophic to autotrophic nitrogen retention in the Elbe River over 35 years of passive restoration
The influence of burn severity on dissolved organic carbon concentrations across a stream network differs based on seasonal wetness conditions
Seasonal particulate organic carbon dynamics of the Kolyma River tributaries, Siberia
Geomorphologic controls and anthropogenic impacts on dissolved organic carbon from mountainous rivers: insights from optical properties and carbon isotopes
Alkalinity generation from carbonate weathering in a silicate-dominated headwater catchment at Iskorasfjellet, northern Norway
Physical and stoichiometric controls on stream respiration in a headwater stream
Local processes with a global impact: unraveling the dynamics of gas evasion in a step-and-pool configuration
Complex dissolved organic matter (DOM) on the roof of the world – Tibetan DOM molecular characteristics indicate sources, land use effects, and processing along the fluvial–limnic continuum
Maximum respiration rates in hyporheic zone sediments are primarily constrained by organic carbon concentration and secondarily by organic matter chemistry
Glacier loss and vegetation expansion alter organic and inorganic carbon dynamics in high-mountain streams
Particulate organic matter in the Lena River and its delta: from the permafrost catchment to the Arctic Ocean
Stable isotopic evidence for the excess leaching of unprocessed atmospheric nitrate from forested catchments under high nitrogen saturation
High-resolution vertical biogeochemical profiles in the hyporheic zone reveal insights into microbial methane cycling
Organic matter transformations are disconnected between surface water and the hyporheic zone
CO2 emissions from peat-draining rivers regulated by water pH
Effects of peatland management on aquatic carbon concentrations and fluxes
Resistance and resilience of stream metabolism to high flow disturbances
Enhanced bioavailability of dissolved organic matter (DOM) in human-disturbed streams in Alpine fluvial networks
Spatial and temporal variability of pCO2 and CO2 emissions from the Dong River in south China
Fluvial carbon dioxide emission from the Lena River basin during the spring flood
Diel patterns in stream nitrate concentration produced by in-stream processes
Complex interactions of in-stream dissolved organic matter and nutrient spiralling unravelled by Bayesian regression analysis
Spatial–temporal variations in riverine carbon strongly influenced by local hydrological events in an alpine catchment
Rapid soil organic carbon decomposition in river systems: effects of the aquatic microbial community and hydrodynamical disturbance
Increased carbon capture by a silicate-treated forested watershed affected by acid deposition
Thermokarst amplifies fluvial inorganic carbon cycling and export across watershed scales on the Peel Plateau, Canada
Temporary and net sinks of atmospheric CO2 due to chemical weathering in subtropical catchment with mixing carbonate and silicate lithology
From canals to the coast: dissolved organic matter and trace metal composition in rivers draining degraded tropical peatlands in Indonesia
Distribution and flux of dissolved iron in the peatland-draining rivers and estuaries of Sarawak, Malaysian Borneo
Comparisons of dissolved organic matter and its optical characteristics in small low and high Arctic catchments
High-frequency measurements explain quantity and quality of dissolved organic carbon mobilization in a headwater catchment
Dissolved inorganic nitrogen in a tropical estuary in Malaysia: transport and transformation
Behaviour of Dissolved Phosphorus with the associated nutrients in relation to phytoplankton biomass of the Rajang River-South China Sea continuum
Synchrony in catchment stream colour levels is driven by both local and regional climate
The post-monsoon carbon biogeochemistry of the Hooghly–Sundarbans estuarine system under different levels of anthropogenic impacts
Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across a 1700 km latitudinal transect
Geochemistry of the dissolved loads during high-flow season of rivers in the southeastern coastal region of China: anthropogenic impact on chemical weathering and carbon sequestration
CO2 partial pressure and CO2 emission along the lower Red River (Vietnam)
Stable isotopes of nitrate reveal different nitrogen processing mechanisms in streams across a land use gradient during wet and dry periods
Riverine carbon export in the arid to semiarid Wuding River catchment on the Chinese Loess Plateau
Use of argon to measure gas exchange in turbulent mountain streams
Reviews and syntheses: Anthropogenic perturbations to carbon fluxes in Asian river systems – concepts, emerging trends, and research challenges
Shifts in stream hydrochemistry in responses to typhoon and non-typhoon precipitation
Selin Kubilay, Edurne Estévez, José Barquín Ortiz, and Gabriel Singer
Biogeosciences, 22, 3279–3300, https://doi.org/10.5194/bg-22-3279-2025, https://doi.org/10.5194/bg-22-3279-2025, 2025
Short summary
Short summary
Here, we studied how dams change the natural flow of rivers and their organic matter dynamics in two different flow regimes in northern Spain. Natural Atlantic rivers showed a higher seasonal turnover of dissolved organic matter (DOM) composition, whereas rivers with dam-altered flow regimes showed more stable DOM characteristics throughout the year. In contrast, we could not find a similar difference between Mediterranean natural and altered rivers.
Aki Vähä, Timo Vesala, Sofya Guseva, Anders Lindroth, Andreas Lorke, Sally MacIntyre, and Ivan Mammarella
Biogeosciences, 22, 1651–1671, https://doi.org/10.5194/bg-22-1651-2025, https://doi.org/10.5194/bg-22-1651-2025, 2025
Short summary
Short summary
Boreal rivers are significant sources of carbon dioxide (CO2) and methane (CH4) for the atmosphere, but the controls of these emissions are uncertain. We measured 4 months of CO2 and CH4 exchanges between a regulated boreal river and the atmosphere with eddy covariance. We found statistical relationships between the gas exchange and several environmental variables, the most important of which were dissolved CO2 partial pressure in water, wind speed and water temperature.
Maggi M. Laan, Stephanie G. Fulton, Vanessa A. Garayburu-Caruso, Morgan E. Barnes, Mikayla A. Borton, Xingyuan Chen, Yuliya Farris, Brieanne Forbes, Amy E. Goldman, Samantha Grieger, Robert O. Hall Jr., Matthew H. Kaufman, Xinming Lin, Erin L. M. Zionce, Sophia A. McKever, Allison Myers-Pigg, Opal Otenburg, Aaron C. Pelly, Huiying Ren, Lupita Renteria, Timothy D. Scheibe, Kyongho Son, Jerry Tagestad, Joshua M. Torgeson, and James C. Stegen
EGUsphere, https://doi.org/10.5194/egusphere-2025-1109, https://doi.org/10.5194/egusphere-2025-1109, 2025
Short summary
Short summary
Respiration is a process that combines carbon and oxygen to generate energy for living organisms. Within a river, respiration in sediments and water have variable contributions to respiration of the whole river system. Contrary to conventional wisdom, we found that water column respiration did not increase systematically moving from small streams to big rivers. Instead, it was locally influenced by temperature, nutrients and suspended solids.
Hayley F. Drapeau, Suzanne E. Tank, Maria A. Cavaco, Jessica A. Serbu, Vincent L. St. Louis, and Maya P. Bhatia
Biogeosciences, 22, 1369–1391, https://doi.org/10.5194/bg-22-1369-2025, https://doi.org/10.5194/bg-22-1369-2025, 2025
Short summary
Short summary
From glacial headwaters to 100 km downstream, we found clear organic matter gradients in Canadian Rocky Mountain rivers. In contrast, microbial communities exhibited overall cohesion, indicating that species dispersal may be an over-riding control on community dynamics in these connected rivers. Identification of glacial-specific microbes suggests that glaciers seed headwater microbial assemblages; these findings show the importance of glacial waters and microbiomes in changing mountain systems.
Eva L. Doting, Ian T. Stevens, Anne M. Kellerman, Pamela E. Rossel, Runa Antony, Amy M. McKenna, Martyn Tranter, Liane G. Benning, Robert G. M. Spencer, Jon R. Hawkings, and Alexandre M. Anesio
Biogeosciences, 22, 41–53, https://doi.org/10.5194/bg-22-41-2025, https://doi.org/10.5194/bg-22-41-2025, 2025
Short summary
Short summary
This study provides the first evidence for biogeochemical cycling of supraglacial dissolved organic matter (DOM) in meltwater flowing through the porous crust of weathering ice that covers glacier ice surfaces during the melt season. Movement of water through the weathering crust is slow, allowing microbes and solar radiation to alter the DOM in glacial meltwaters. This is important as supraglacial meltwaters deliver DOM to downstream aquatic environments.
Artem V. Chupakov, Natalia V. Neverova, Anna A. Chupakova, Svetlana A. Zabelina, Liudmila S. Shirokova, Taissia Ya. Vorobyeva, and Oleg S. Pokrovsky
Biogeosciences, 21, 5725–5743, https://doi.org/10.5194/bg-21-5725-2024, https://doi.org/10.5194/bg-21-5725-2024, 2024
Short summary
Short summary
In the boreal humic waters of a forest lake and bog, the rate of dissolved organic matter photodegradation is 4 times higher than that of biodegradation. However, given the shallow, light-penetrating layer, the biodegradation provides the largest contribution to CO2 emissions from water surfaces. Trace metals were partially removed (1–10 %) during photodegradation and biodegradation via precipitation of Fe(III) hydroxides after destabilization of organoferric colloids and organic complexes.
Thibault Lambert, Rémi Dupas, and Patrick Durand
Biogeosciences, 21, 4533–4547, https://doi.org/10.5194/bg-21-4533-2024, https://doi.org/10.5194/bg-21-4533-2024, 2024
Short summary
Short summary
This study investigates dissolved organic carbon (DOC) export in headwater catchments. Results show small links between DOC, nitrates, and the iron cycle throughout the year, calling into question our current conceptualization of DOC export at the catchment scale. Indeed, this study evidences that the winter period, referred as a non-productive period in our current conceptual model, acts as an active period for DOC production in riparian soils and DOC export toward stream waters.
Alexander Wachholz, James W. Jawitz, and Dietrich Borchardt
Biogeosciences, 21, 3537–3550, https://doi.org/10.5194/bg-21-3537-2024, https://doi.org/10.5194/bg-21-3537-2024, 2024
Short summary
Short summary
Human activities are rivers' main source of nitrogen, causing eutrophication and other hazards. However, rivers can serve as a natural defense mechanism against this by retaining nitrogen. We show that the Elbe River retains more nitrogen during times of high pollution. With improvements in water quality, less nitrogen is retained. We explain this with changed algal and bacterial activities, which correspond to pollution and have many implications for the river and adjacent ecosystems.
Katie A. Wampler, Kevin D. Bladon, and Allison N. Myers-Pigg
Biogeosciences, 21, 3093–3120, https://doi.org/10.5194/bg-21-3093-2024, https://doi.org/10.5194/bg-21-3093-2024, 2024
Short summary
Short summary
Following a high-severity wildfire, we sampled 129 sites during four different times of the year across a stream network to quantify dissolved organic carbon. The results from our study suggested that dissolved organic carbon may decrease with increasing burn severity. They also suggest that landscape characteristics can override wildfire impacts, with the seasonal timing of sampling influencing the observed response of dissolved organic carbon concentrations to wildfire.
Kirsi H. Keskitalo, Lisa Bröder, Tommaso Tesi, Paul J. Mann, Dirk J. Jong, Sergio Bulte Garcia, Anna Davydova, Sergei Davydov, Nikita Zimov, Negar Haghipour, Timothy I. Eglinton, and Jorien E. Vonk
Biogeosciences, 21, 357–379, https://doi.org/10.5194/bg-21-357-2024, https://doi.org/10.5194/bg-21-357-2024, 2024
Short summary
Short summary
Permafrost thaw releases organic carbon into waterways. Decomposition of this carbon pool emits greenhouse gases into the atmosphere, enhancing climate warming. We show that Arctic river carbon and water chemistry are different between the spring ice breakup and summer and that primary production is initiated in small Arctic rivers right after ice breakup, in contrast to in large rivers. This may have implications for fluvial carbon dynamics and greenhouse gas uptake and emission balance.
Shuai Chen, Jun Zhong, Lishan Ran, Yuanbi Yi, Wanfa Wang, Zelong Yan, Si-liang Li, and Khan M. G. Mostofa
Biogeosciences, 20, 4949–4967, https://doi.org/10.5194/bg-20-4949-2023, https://doi.org/10.5194/bg-20-4949-2023, 2023
Short summary
Short summary
This study found the source of dissolved organic carbon and its optical properties (e.g., aromaticity, humification) are related to human land use and catchment slope in anthropogenically impacted subtropical mountainous rivers. The study highlights that the combination of dual carbon isotopes and optical properties represents a useful tool in tracing the origin of dissolved organic carbon and its in-stream processes.
Nele Lehmann, Hugues Lantuit, Michael Ernst Böttcher, Jens Hartmann, Antje Eulenburg, and Helmuth Thomas
Biogeosciences, 20, 3459–3479, https://doi.org/10.5194/bg-20-3459-2023, https://doi.org/10.5194/bg-20-3459-2023, 2023
Short summary
Short summary
Riverine alkalinity in the silicate-dominated headwater catchment at subarctic Iskorasfjellet, northern Norway, was almost entirely derived from weathering of minor carbonate occurrences in the riparian zone. The uphill catchment appeared limited by insufficient contact time of weathering agents and weatherable material. Further, alkalinity increased with decreasing permafrost extent. Thus, with climate change, alkalinity generation is expected to increase in this permafrost-degrading landscape.
Jancoba Dorley, Joel Singley, Tim Covino, Kamini Singha, Michael Gooseff, David Van Horn, and Ricardo González-Pinzón
Biogeosciences, 20, 3353–3366, https://doi.org/10.5194/bg-20-3353-2023, https://doi.org/10.5194/bg-20-3353-2023, 2023
Short summary
Short summary
We quantified how microbial respiration is controlled by discharge and the supply of C, N, and P in a stream. We ran two rounds of experiments adding a conservative tracer, an indicator of aerobic respiration, and nutrient treatments: a) N, b) N+C, c) N+P, and d) C+N+P. Microbial respiration remained similar between rounds and across nutrient treatments. This suggests that complex interactions between hydrology, resource supply, and biological community drive in-stream respiration.
Paolo Peruzzo, Matteo Cappozzo, Nicola Durighetto, and Gianluca Botter
Biogeosciences, 20, 3261–3271, https://doi.org/10.5194/bg-20-3261-2023, https://doi.org/10.5194/bg-20-3261-2023, 2023
Short summary
Short summary
Small cascades greatly enhance mountain stream gas emissions through the turbulent energy dissipation rate and air bubbles entrained into the water. We numerically studied the local contribution of these mechanisms driving gas transfer velocity used to quantify the outgassing. The gas evasion is primarily due to bubbles concentrated in irregular spots of limited area. Consequently, the gas exchange velocity is scale-dependent and unpredictable, posing concerns about its use in similar scenarios.
Philipp Maurischat, Michael Seidel, Thorsten Dittmar, and Georg Guggenberger
Biogeosciences, 20, 3011–3026, https://doi.org/10.5194/bg-20-3011-2023, https://doi.org/10.5194/bg-20-3011-2023, 2023
Short summary
Short summary
Production and consumption of organic matter (OM) on the Tibetan Plateau are important for this sensitive ecosystem. We investigated the chemical composition of dissolved organic matter and the most mobile fraction of OM in glaciers, wetlands, and groundwater as well as in the rivers and a large terminal lake. Our data show that the sources differ in the molecular composition of OM, that the stream is influenced by agriculture, and that the lake strongly changes the inflowing organic matter.
James C. Stegen, Vanessa A. Garayburu-Caruso, Robert E. Danczak, Amy E. Goldman, Lupita Renteria, Joshua M. Torgeson, and Jacqueline Hager
Biogeosciences, 20, 2857–2867, https://doi.org/10.5194/bg-20-2857-2023, https://doi.org/10.5194/bg-20-2857-2023, 2023
Short summary
Short summary
Chemical reactions in river sediments influence how clean the water is and how much greenhouse gas comes out of a river. Our study investigates why some sediments have higher rates of chemical reactions than others. We find that to achieve high rates, sediments need to have two things: only a few different kinds of molecules, but a lot of them. This result spans about 80 rivers such that it could be a general rule, helpful for predicting the future of rivers and our planet.
Andrew L. Robison, Nicola Deluigi, Camille Rolland, Nicolas Manetti, and Tom Battin
Biogeosciences, 20, 2301–2316, https://doi.org/10.5194/bg-20-2301-2023, https://doi.org/10.5194/bg-20-2301-2023, 2023
Short summary
Short summary
Climate change is affecting mountain ecosystems intensely, including the loss of glaciers and the uphill migration of plants. How these changes will affect the streams draining these landscapes is unclear. We sampled streams across a gradient of glacier and vegetation cover in Switzerland and found glacier loss reduced the carbon dioxide sink from weathering, while vegetation cover increased dissolved organic carbon in the stream. These changes are important to consider for mountains globally.
Olga Ogneva, Gesine Mollenhauer, Bennet Juhls, Tina Sanders, Juri Palmtag, Matthias Fuchs, Hendrik Grotheer, Paul J. Mann, and Jens Strauss
Biogeosciences, 20, 1423–1441, https://doi.org/10.5194/bg-20-1423-2023, https://doi.org/10.5194/bg-20-1423-2023, 2023
Short summary
Short summary
Arctic warming accelerates permafrost thaw and release of terrestrial organic matter (OM) via rivers to the Arctic Ocean. We compared particulate organic carbon (POC), total suspended matter, and C isotopes (δ13C and Δ14C of POC) in the Lena delta and Lena River along a ~1600 km transect. We show that the Lena delta, as an interface between the Lena River and the Arctic Ocean, plays a crucial role in determining the qualitative and quantitative composition of OM discharged into the Arctic Ocean.
Weitian Ding, Urumu Tsunogai, Fumiko Nakagawa, Takashi Sambuichi, Masaaki Chiwa, Tamao Kasahara, and Ken'ichi Shinozuka
Biogeosciences, 20, 753–766, https://doi.org/10.5194/bg-20-753-2023, https://doi.org/10.5194/bg-20-753-2023, 2023
Short summary
Short summary
By monitoring the concentration and Δ17O of stream nitrate in three forested streams, the new nitrogen saturation index of forested catchments (Matm/Datm ratio) was estimated. We found that (1) the unprocessed atmospheric nitrate in our studied forested stream (FK1 catchment) was the highest ever reported in forested streams; (2) the Matm/Datm ratio can be used as a robust index for evaluating nitrogen saturation in forested catchments as the Matm/Datm ratio is independent of the precipitation.
Tamara Michaelis, Anja Wunderlich, Ömer K. Coskun, William Orsi, Thomas Baumann, and Florian Einsiedl
Biogeosciences, 19, 4551–4569, https://doi.org/10.5194/bg-19-4551-2022, https://doi.org/10.5194/bg-19-4551-2022, 2022
Short summary
Short summary
The greenhouse gas methane (CH4) drives climate change. Microorganisms in river sediments produce CH4 when degrading organic matter, but the contribution of rivers to atmospheric CH4 concentrations is uncertain. To better understand riverine CH4 cycling, we measured concentration profiles of CH4 and relevant reactants that might influence the CH4 cycle. We found substantial CH4 production, especially in fine, organic-rich sediments during summer and signs of microbial CH4 consumption.
James C. Stegen, Sarah J. Fansler, Malak M. Tfaily, Vanessa A. Garayburu-Caruso, Amy E. Goldman, Robert E. Danczak, Rosalie K. Chu, Lupita Renteria, Jerry Tagestad, and Jason Toyoda
Biogeosciences, 19, 3099–3110, https://doi.org/10.5194/bg-19-3099-2022, https://doi.org/10.5194/bg-19-3099-2022, 2022
Short summary
Short summary
Rivers are vital to Earth, and in rivers, organic matter (OM) is an energy source for microbes that make greenhouse gas and remove contaminants. Predicting Earth’s future requires understanding how and why river OM is transformed. Our results help meet this need. We found that the processes influencing OM transformations diverge between river water and riverbed sediments. This can be used to build new models for predicting the future of rivers and, in turn, the Earth system.
Alexandra Klemme, Tim Rixen, Denise Müller-Dum, Moritz Müller, Justus Notholt, and Thorsten Warneke
Biogeosciences, 19, 2855–2880, https://doi.org/10.5194/bg-19-2855-2022, https://doi.org/10.5194/bg-19-2855-2022, 2022
Short summary
Short summary
Tropical peat-draining rivers contain high amounts of carbon. Surprisingly, measured carbon dioxide (CO2) emissions from those rivers are comparatively moderate. We compiled data from 10 Southeast Asian rivers and found that CO2 production within these rivers is hampered by low water pH, providing a natural threshold for CO2 emissions. Furthermore, we find that enhanced carbonate input, e.g. caused by human activities, suspends this natural threshold and causes increased CO2 emissions.
Amy E. Pickard, Marcella Branagan, Mike F. Billett, Roxane Andersen, and Kerry J. Dinsmore
Biogeosciences, 19, 1321–1334, https://doi.org/10.5194/bg-19-1321-2022, https://doi.org/10.5194/bg-19-1321-2022, 2022
Short summary
Short summary
Peatlands have been subject to a range of land management regimes over the past century. This has affected the amount of carbon that drains into surrounding streams and rivers. In our study, we measured carbon concentrations in streams draining from drained, non-drained, and restored areas of the Flow Country blanket bog in N Scotland. We found that drained peatland had higher concentrations and fluxes of carbon relative to non-drained areas. Restored peatland areas were highly variable.
Brynn O'Donnell and Erin R. Hotchkiss
Biogeosciences, 19, 1111–1134, https://doi.org/10.5194/bg-19-1111-2022, https://doi.org/10.5194/bg-19-1111-2022, 2022
Short summary
Short summary
A stream is defined by flowing water, but higher flow from storms is also a frequent disturbance. This paper tests how higher flow changes stream metabolism (respiration and photosynthesis, R and P). P was less resistant to changes in flow compared to R, and P took longer to recover from storms than R (2.2 versus 0.6 d). Further work on metabolic responses to flow disturbance is critical given projected increases in storms and the influence of higher flows on ecosystem health and functioning.
Thibault Lambert, Pascal Perolo, Nicolas Escoffier, and Marie-Elodie Perga
Biogeosciences, 19, 187–200, https://doi.org/10.5194/bg-19-187-2022, https://doi.org/10.5194/bg-19-187-2022, 2022
Short summary
Short summary
The bacterial mineralization of dissolved organic matter (DOM) in inland waters contributes to CO2 emissions to the atmosphere. Human activities affect DOM sources. However, the implications on DOM mineralization are poorly known. Combining sampling and incubations, we showed that higher bacterial respiration in agro-urban streams related to a labile pool from aquatic origin. Therefore, human activities may have a limited impact on the net carbon exchanges between inland waters and atmosphere.
Boyi Liu, Mingyang Tian, Kaimin Shih, Chun Ngai Chan, Xiankun Yang, and Lishan Ran
Biogeosciences, 18, 5231–5245, https://doi.org/10.5194/bg-18-5231-2021, https://doi.org/10.5194/bg-18-5231-2021, 2021
Short summary
Short summary
Spatial and temporal patterns of pCO2 in the subtropical Dong River basin were mainly affected by C inputs and in-stream metabolism, both of which varied due to differential catchment settings, land cover, and hydrological conditions. CO2 fluxes in the wet season were 2-fold larger than in the dry season due to high pCO2 and turbulence caused by high flow velocity. The absence of high CO2 fluxes in small rivers could be associated with the depletion effect caused by abundant precipitation.
Sergey N. Vorobyev, Jan Karlsson, Yuri Y. Kolesnichenko, Mikhail A. Korets, and Oleg S. Pokrovsky
Biogeosciences, 18, 4919–4936, https://doi.org/10.5194/bg-18-4919-2021, https://doi.org/10.5194/bg-18-4919-2021, 2021
Short summary
Short summary
In order to quantify riverine carbon (C) exchange with the atmosphere in permafrost regions, we report a first assessment of CO2 and CH4 concentration and fluxes of the largest permafrost-affected river, the Lena River, during the peak of spring flow. The results allowed identification of environmental factors controlling GHG concentrations and emission in the Lena River watershed; this new knowledge can be used for foreseeing future changes in C balance in permafrost-affected Arctic rivers.
Jan Greiwe, Markus Weiler, and Jens Lange
Biogeosciences, 18, 4705–4715, https://doi.org/10.5194/bg-18-4705-2021, https://doi.org/10.5194/bg-18-4705-2021, 2021
Short summary
Short summary
We analyzed variability in diel nitrate patterns at three locations in a lowland stream. Comparison of time lags between monitoring sites with water travel time indicated that diel patterns were created by in-stream processes rather than transported downstream from an upstream point of origin. Most of the patterns (70 %) could be explained by assimilatory nitrate uptake. The remaining patterns suggest seasonally varying dominance and synchronicity of different biochemical processes.
Matthias Pucher, Peter Flödl, Daniel Graeber, Klaus Felsenstein, Thomas Hein, and Gabriele Weigelhofer
Biogeosciences, 18, 3103–3122, https://doi.org/10.5194/bg-18-3103-2021, https://doi.org/10.5194/bg-18-3103-2021, 2021
Short summary
Short summary
Dissolved organic matter is an important carbon source in aquatic ecosystems, yet the uptake processes are not totally understood. We found evidence for the release of degradation products, efficiency loss in the uptake with higher concentrations, stimulating effects, and quality-dependent influences from the benthic zone. To conduct this analysis, we included interactions in the equations of the nutrient spiralling concept and solve it with a Bayesian non-linear fitting algorithm.
Xin Wang, Ting Liu, Liang Wang, Zongguang Liu, Erxiong Zhu, Simin Wang, Yue Cai, Shanshan Zhu, and Xiaojuan Feng
Biogeosciences, 18, 3015–3028, https://doi.org/10.5194/bg-18-3015-2021, https://doi.org/10.5194/bg-18-3015-2021, 2021
Short summary
Short summary
We show a comprehensive monitoring dataset on the discharge and carbon transport in a small alpine river on the Qinghai–Tibetan Plateau, where riverine carbon increased downstream in the pre-monsoon season due to an increasing contribution of organic matter derived from seasonal permafrost thaw while it fluctuated in the monsoon season induced by sporadic precipitation. These results indicate a high sensitivity of riverine carbon in alpine headwater catchments to local hydrological events.
Man Zhao, Liesbet Jacobs, Steven Bouillon, and Gerard Govers
Biogeosciences, 18, 1511–1523, https://doi.org/10.5194/bg-18-1511-2021, https://doi.org/10.5194/bg-18-1511-2021, 2021
Short summary
Short summary
We investigate the relative importance of two individual factors (hydrodynamical disturbance and aquatic microbial community) that possibly control SOC decomposition rates in river systems. We found aquatic microbial organisms led to rapid SOC decomposition, while effect of mechanical disturbance is relative minor. We propose a simple conceptual model: hydrodynamic disturbance is only important when soil aggregates are strong enough to withstand the disruptive forces imposed by water immersions.
Lyla L. Taylor, Charles T. Driscoll, Peter M. Groffman, Greg H. Rau, Joel D. Blum, and David J. Beerling
Biogeosciences, 18, 169–188, https://doi.org/10.5194/bg-18-169-2021, https://doi.org/10.5194/bg-18-169-2021, 2021
Short summary
Short summary
Enhanced rock weathering (ERW) is a carbon dioxide removal (CDR) strategy involving soil amendments with silicate rock dust. Over 15 years, a small silicate application led to net CDR of 8.5–11.5 t CO2/ha in an acid-rain-impacted New Hampshire forest. We accounted for the total carbon cost of treatment and compared effects with an adjacent, untreated forest. Our results suggest ERW can improve the greenhouse gas balance of similar forests in addition to mitigating acid rain effects.
Scott Zolkos, Suzanne E. Tank, Robert G. Striegl, Steven V. Kokelj, Justin Kokoszka, Cristian Estop-Aragonés, and David Olefeldt
Biogeosciences, 17, 5163–5182, https://doi.org/10.5194/bg-17-5163-2020, https://doi.org/10.5194/bg-17-5163-2020, 2020
Short summary
Short summary
High-latitude warming thaws permafrost, exposing minerals to weathering and fluvial transport. We studied the effects of abrupt thaw and associated weathering on carbon cycling in western Canada. Permafrost collapse affected < 1 % of the landscape yet enabled carbonate weathering associated with CO2 degassing in headwaters and increased bicarbonate export across watershed scales. Weathering may become a driver of carbon cycling in ice- and mineral-rich permafrost terrain across the Arctic.
Yingjie Cao, Yingxue Xuan, Changyuan Tang, Shuai Guan, and Yisheng Peng
Biogeosciences, 17, 3875–3890, https://doi.org/10.5194/bg-17-3875-2020, https://doi.org/10.5194/bg-17-3875-2020, 2020
Short summary
Short summary
About half of the global CO2 sequestration due to chemical weathering occurs in warm and high-runoff regions. To evaluate the temporary and net sinks of atmospheric CO2 due to chemical weathering, we selected a typical subtropical catchment as our study area and did fieldwork to sample surface water along the main channel and major tributaries in 1 hydrological year. The result of mass balance calculation showed that human activities dramatically decreased the CO2 net sink.
Laure Gandois, Alison M. Hoyt, Stéphane Mounier, Gaël Le Roux, Charles F. Harvey, Adrien Claustres, Mohammed Nuriman, and Gusti Anshari
Biogeosciences, 17, 1897–1909, https://doi.org/10.5194/bg-17-1897-2020, https://doi.org/10.5194/bg-17-1897-2020, 2020
Short summary
Short summary
Worldwide, peatlands are important sources of dissolved organic matter (DOM) and trace metals (TMs) to surface waters, and these fluxes may increase with peatland degradation. In Southeast Asia, tropical peatlands are being rapidly deforested and drained. This work aims to address the fate of organic carbon and its role as a trace metal carrier in drained peatlands of Indonesia.
Xiaohui Zhang, Moritz Müller, Shan Jiang, Ying Wu, Xunchi Zhu, Aazani Mujahid, Zhuoyi Zhu, Mohd Fakharuddin Muhamad, Edwin Sien Aun Sia, Faddrine Holt Ajon Jang, and Jing Zhang
Biogeosciences, 17, 1805–1819, https://doi.org/10.5194/bg-17-1805-2020, https://doi.org/10.5194/bg-17-1805-2020, 2020
Short summary
Short summary
This study offered detailed information on dFe concentrations, distribution and the magnitude of yield in the Rajang River, the largest river in Malaysia. Three blackwater rivers, draining from peatlands, were also included in our study. Compared with the Rajang River, the dFe concentrations and yield from three blackwater rivers were much higher. The precipitation and agricultural activities, such as palm oil plantations, may markedly increase the concentration dFe in these tropical rivers.
Caroline Coch, Bennet Juhls, Scott F. Lamoureux, Melissa J. Lafrenière, Michael Fritz, Birgit Heim, and Hugues Lantuit
Biogeosciences, 16, 4535–4553, https://doi.org/10.5194/bg-16-4535-2019, https://doi.org/10.5194/bg-16-4535-2019, 2019
Short summary
Short summary
Climate change affects Arctic ecosystems. This includes thawing of permafrost (ground below 0 °C) and an increase in rainfall. Both have substantial impacts on the chemical composition of river water. We compared the composition of small rivers in the low and high Arctic with the large Arctic rivers. In comparison, dissolved organic matter in the small rivers is more susceptible to degradation; thus, it could potentially increase carbon dioxide emissions. Rainfall events have a similar effect.
Benedikt J. Werner, Andreas Musolff, Oliver J. Lechtenfeld, Gerrit H. de Rooij, Marieke R. Oosterwoud, and Jan H. Fleckenstein
Biogeosciences, 16, 4497–4516, https://doi.org/10.5194/bg-16-4497-2019, https://doi.org/10.5194/bg-16-4497-2019, 2019
Short summary
Short summary
Increased dissolved organic carbon (DOC) concentration in streams can pose a threat to downstream water resources. Analyzing data from an in-stream probe we found that hydroclimatic and hydrological drivers can describe up to 72 % of the observed DOC concentration and composition variability. Variability was found to be highest during discharge events with warm and dry preconditions. The findings suggest an impact of climate change on DOC exports and thus also on downstream water quality.
Shan Jiang, Moritz Müller, Jie Jin, Ying Wu, Kun Zhu, Guosen Zhang, Aazani Mujahid, Tim Rixen, Mohd Fakharuddin Muhamad, Edwin Sien Aun Sia, Faddrine Holt Ajon Jang, and Jing Zhang
Biogeosciences, 16, 2821–2836, https://doi.org/10.5194/bg-16-2821-2019, https://doi.org/10.5194/bg-16-2821-2019, 2019
Short summary
Short summary
Three cruises were conducted in the Rajang River estuary, Malaysia. The results revealed that the decomposition of terrestrial organic matter and the subsequent soil leaching were the main sources of dissolved inorganic nitrogen (DIN) in the fresh river water. Porewater exchange and ammonification enhanced DIN concentrations in the estuary water, while intensities of DIN addition varied between seasons. The riverine DIN flux could reach 101.5 ton(N) / d, supporting the coastal primary producers.
Edwin Sien Aun Sia, Jing Zhang, Shan Jiang, Zhuoyi Zhu, Gonzalo Carrasco, Faddrine Holt Jang, Aazani Mujahid, and Moritz Müller
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-219, https://doi.org/10.5194/bg-2019-219, 2019
Revised manuscript not accepted
Short summary
Short summary
Nutrient loads carried by large rivers and discharged into the continental shelf and coastal waters are vital to support primary production. Our knowledge of tropical river systems is fragmented with very few seasonal studies available for Southeast Asia (SEA). We present data from three sampling campaigns on the longest river in Malaysia, the Rajang river. Our results show the generalization of SEA as a nutrient hotspot might not hold true for all regions and requires further investigation.
Brian C. Doyle, Elvira de Eyto, Mary Dillane, Russell Poole, Valerie McCarthy, Elizabeth Ryder, and Eleanor Jennings
Biogeosciences, 16, 1053–1071, https://doi.org/10.5194/bg-16-1053-2019, https://doi.org/10.5194/bg-16-1053-2019, 2019
Short summary
Short summary
This study explores the drivers of variation in the water colour of rivers, and hence organic carbon export, in a blanket peatland catchment. We used 6 years of weekly river water colour data (2011 to 2016) from three proximate river sub-catchments in western Ireland. in tandem with a range of topographical, hydrological and climate data, to discover the principle environmental drivers controlling changes in colour concentration in the rivers.
Manab Kumar Dutta, Sanjeev Kumar, Rupa Mukherjee, Prasun Sanyal, and Sandip Kumar Mukhopadhyay
Biogeosciences, 16, 289–307, https://doi.org/10.5194/bg-16-289-2019, https://doi.org/10.5194/bg-16-289-2019, 2019
Short summary
Short summary
The study focused on understanding C biogeochemistry of two adjacently located estuaries undergoing different levels of anthropogenic stresses. Different parameters related to C cycling were measured in an anthropogenically influenced and a mangrove-dominated estuary. Although the entire estuarine system acted as a source of carbon dioxide to the regional atmosphere, emission approximately 17 times higher was noticed from the anthropogenically affected estuary compared to mangrove-dominated one.
Ivan V. Krickov, Artem G. Lim, Rinat M. Manasypov, Sergey V. Loiko, Liudmila S. Shirokova, Sergey N. Kirpotin, Jan Karlsson, and Oleg S. Pokrovsky
Biogeosciences, 15, 6867–6884, https://doi.org/10.5194/bg-15-6867-2018, https://doi.org/10.5194/bg-15-6867-2018, 2018
Short summary
Short summary
We tested the effect of climate, permafrost and physio-geographical landscape parameters on particulate C, N and P concentrations in small- and medium- sized rivers in the Western Siberian Lowland (WSL). We discovered a maximum of particulate C and N concentrations at the beginning of the permafrost appearance. A northward shift of permafrost boundaries may increase the particulate C and N export by WSL rivers to the Arctic Ocean by a factor of 2.
Wenjing Liu, Zhifang Xu, Huiguo Sun, Tong Zhao, Chao Shi, and Taoze Liu
Biogeosciences, 15, 4955–4971, https://doi.org/10.5194/bg-15-4955-2018, https://doi.org/10.5194/bg-15-4955-2018, 2018
Short summary
Short summary
The southeastern coastal region is the top acid-rain-impacted area in China. It is worth evaluating the acid deposition impacts on chemical weathering and CO2 consumption there. River water geochemistry evidenced an overestimation of CO2 sequestration if H2SO4/HNO3 involvement was ignored, which accounted for 33.6 % of the total flux by silicate weathering in this area. This study quantitatively highlights the anthropogenic acid effects on chemical weathering and associated CO2 consumption.
Thi Phuong Quynh Le, Cyril Marchand, Cuong Tu Ho, Nhu Da Le, Thi Thuy Duong, XiXi Lu, Phuong Kieu Doan, Trung Kien Nguyen, Thi Mai Huong Nguyen, and Duy An Vu
Biogeosciences, 15, 4799–4814, https://doi.org/10.5194/bg-15-4799-2018, https://doi.org/10.5194/bg-15-4799-2018, 2018
Short summary
Short summary
The Red River is a typical south-east Asian river, strongly affected by climate and human activity. This study showed the spatial and seasonal variability of CO2 emissions at the water–air interface of the lower part of this river due to natural conditions (meteo-hydrological-geomorphological characteristics) and human activities (dam impoundment, population, land use). The Red River water was supersaturated with CO2, providing a mean water–air CO2 flux of 530 ± 17 mmol m−2 d−1.
Wei Wen Wong, Jesse Pottage, Fiona Y. Warry, Paul Reich, Keryn L. Roberts, Michael R. Grace, and Perran L. M. Cook
Biogeosciences, 15, 3953–3965, https://doi.org/10.5194/bg-15-3953-2018, https://doi.org/10.5194/bg-15-3953-2018, 2018
Short summary
Short summary
Over-enrichment of nitrate can pose substantial risk to the quality of freshwater ecosystems. Hence, understanding the dynamics of nitrate is the key to better management of waterways. This study evaluates the relationship between the effects of land use and rainfall on the major sources and processing of nitrate within and between five streams in five catchments spanning an agricultural land use gradient. We found that rainfall exerted significant control over the fate of nitrate.
Lishan Ran, Mingyang Tian, Nufang Fang, Suiji Wang, Xixi Lu, Xiankun Yang, and Frankie Cho
Biogeosciences, 15, 3857–3871, https://doi.org/10.5194/bg-15-3857-2018, https://doi.org/10.5194/bg-15-3857-2018, 2018
Short summary
Short summary
We systematically assessed the transport and fate of riverine carbon in the moderate-sized Wuding catchment on the Chinese Loess Plateau by constructing a riverine carbon budget and further relating it to terrestrial ecosystem productivity. The riverine carbon export accounted for 16 % of the catchment's net ecosystem production (NEP). It seems that a significant fraction of terrestrial NEP in this catchment is laterally transported from the terrestrial biosphere to the drainage network.
Robert O. Hall Jr. and Hilary L. Madinger
Biogeosciences, 15, 3085–3092, https://doi.org/10.5194/bg-15-3085-2018, https://doi.org/10.5194/bg-15-3085-2018, 2018
Short summary
Short summary
Streams exchange oxygen with the atmosphere, but this rate is difficult to measure. We added argon to small mountain streams to estimate gas exchange. We compared these rates with sulfur hexafluoride, an intense greenhouse gas. Argon worked well to measure gas exchange, but had higher-than-predicted rates than sulfur hexafluoride. Argon exchange is more likely to represent that for oxygen because they share similar physical properties. We suggest argon to measure gas exchange in small streams.
Ji-Hyung Park, Omme K. Nayna, Most S. Begum, Eliyan Chea, Jens Hartmann, Richard G. Keil, Sanjeev Kumar, Xixi Lu, Lishan Ran, Jeffrey E. Richey, Vedula V. S. S. Sarma, Shafi M. Tareq, Do Thi Xuan, and Ruihong Yu
Biogeosciences, 15, 3049–3069, https://doi.org/10.5194/bg-15-3049-2018, https://doi.org/10.5194/bg-15-3049-2018, 2018
Short summary
Short summary
Human activities are drastically altering water and material flows in river systems across Asia. This review provides a conceptual framework for assessing the human impacts on Asian river C fluxes and an update on anthropogenic alterations of riverine C fluxes, focusing on the impacts of water pollution and river impoundments on CO2 outgassing from the rivers draining South, Southeast, and East Asian regions that account for the largest fraction of river discharge and C exports from Asia.
Chung-Te Chang, Jr-Chuan Huang, Lixin Wang, Yu-Ting Shih, and Teng-Chiu Lin
Biogeosciences, 15, 2379–2391, https://doi.org/10.5194/bg-15-2379-2018, https://doi.org/10.5194/bg-15-2379-2018, 2018
Short summary
Short summary
Our analysis of ion input–output budget illustrates that hydrochemical responses to typhoon storms are distinctly different from those of regular storms. In addition, even mild land use change may have large impacts on nutrient exports/losses. We propose that hydrological models should separate hydrochemical processes into regular and extreme conditions to better capture the whole spectrum of hydrochemical responses to a variety of climate conditions.
Cited articles
Amann, T., Weiss, A., and Hartmann, J.: Silica fluxes in the inner Elbe
Estuary, Germany, Biogeochemistry, 118, 389–412, https://doi.org/10.1007/s10533-013-9940-3,
2014.
Bahlmann, E., Bernasconi, S. M., Bouillon, S., Houtekamer, M., Korntheuer,
M., Langenberg, F., Mayr, C., Metzke, M., Middelburg, J. J., Nagel, B.,
Struck, U., Voß, M., and Emeis, K.-C.: Performance evaluation of
nitrogen isotope ratio determination in marine and lacustrine sediments: An
inter-laboratory comparison, Org. Geochem., 41, 3–12,
https://doi.org/10.1016/j.orggeochem.2009.05.008, 2010.
Belser, L. W. and Mays, E. L.: Specific-Inhibition of Nitrite Oxidation by
Chlorate and Its Use in Assessing Nitrification in Soils and Sediments,
Appl. Environ. Microbiol., 39, 505–510, 1980.
Bergemann, T. and Gaumert, M.: Elbebericht 2008, Flussgebietsgemeinschaft Elbe, Hamburg, Germany, 2010.
Böhlke, J. K., Smith, R. L., and Hannon, J. E.: Isotopic analysis of N
and O in nitrite and nitrate by sequential selective bacterial reduction to
N2O, Anal. Chem., 79, 5888–5895, 2007.
Bonaglia, S., Deutsch, B., Bartoli, M., Marchant, H. K., and Bruchert, V.:
Seasonal oxygen, nitrogen and phosphorus benthic cycling along an impacted
Baltic Sea estuary: regulation and spatial patterns, Biogeochemistry, 119,
139–160, https://doi.org/10.1007/s10533-014-9953-6, 2014.
Brandes, J. A. and Devol, A. H.: Isotopic fractionation of oxygen and
nitrogen in coastal marine sediments, Geochim. Cosmochim. Ac., 61,
1793–1801, 1997.
Brandes, J. A. and Devol, A. H.: A global marine-fixed nitrogen isotopic
budget: Implications for Holocene nitrogen cycling, Global Biogeochem.
Cy., 16, 1120, https://doi.org/10.1029/2001GB001856, 2002.
Brandes, J. A., Devol, A. H., Yoshinari, T., Jayakumar, D. A., and Naqvi, S.
W. A.: Isotopic composition of nitrate in the central Arabian Sea and
eastern tropical North Pacific: A tracer for mixing and nitrogen cycles,
Limnol. Oceanogr., 43, 1680–1689, 1998.
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, 2017.
Buchwald, C., Santoro, A. E., McIlvin, M. R., and Casciotti, K. L.: Oxygen
isotopic composition of nitrate and nitrite produced by nitrifying
cocultures and natural marine assemblages, Limnol. Oceanogr., 57,
1361–1375, https://doi.org/10.4319/lo.2012.57.5.1361, 2012.
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, Global Biogeochem. Cy., 29, 2061–2081, https://doi.org/10.1002/2015gb005187, 2015.
Burchard, H., Schuttelaars, H. M., and Ralston, D. K.: Sediment Trapping in
Estuaries, Ann. Rev. Mar. Sci., 10, 371–395,
https://doi.org/10.1146/annurev-marine-010816-060535, 2018.
Casciotti, K. L.: Inverse kinetic isotope fractionation during bacterial
nitrite oxidation, Geochim. Cosmochim. Ac., 73, 2061–2076, 2009.
Casciotti, K. L., Sigman, D. M., Hastings, M. G., Bohlke, 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, 2002.
Casciotti, K. L., Sigman, D. M., and Ward, B. B.: Linking diversity and
stable isotope fractionation in ammonia-oxidizing bacteria, Geomicrobiol.
J., 20, 335–353, 2003.
Dähnke, K., Bahlmann, E., and Emeis, K.: A nitrate sink in estuaries? An
assessment by means of stable nitrate isotopes in the Elbe estuary,
Limnol. Oceanogr., 53, 1504–1511, 2008.
Dähnke, K., Emeis, K., Johannsen, A., and Nagel, B.: Stable isotope
composition and turnover of nitrate in the German Bight, Mar. Ecol.
Prog. Ser., 408, 7–18, 2010.
Deek, A., Dähnke, K., van Beusekom, J., Meyer, S., Voss, M., and Emeis,
K.: 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.
DIN15685: Bodenbeschaffenheit – Bestimmung der potentiellen
Nitrifizierung – Schnellverfahren mittels Ammoniumoxidation. Deutsches
Institut für Normung e.V., Beuth Verlag, Berlin, 2001.
Dortch, O., Thompson, P. A., and Harrison, P. J.: Short-Term Interaction
between Nitrate and Ammonium Uptake in Thalassiosira-Pseudonana – Effect of
Preconditioning Nitrogen-Source and Growth-Rate, Mar. Biol., 110,
183–193, 1991.
Eyre, B. and Balls, P.: A comparative study of nutrient behavior along the
salinity gradient of tropical and temperate estuaries, Estuaries, 22,
313–326, 1999.
Fry, B.: Conservative mixing of stable isotopes across estuarine salinity
gradients: A conceptual framework for monitoring watershed influences on
downstream fisheries production, Estuaries, 25, 264–271, 2002.
Galloway, J. N., Aber, J. D., Erisman, J. W., Seitzinger, S. P., Howarth, R.
W., Cowling, E. B., and Cosby, B. J.: The nitrogen cascade, Bioscience, 53,
341–356, 2003.
Garnier, J., Billen, G., Némery, J., and Sebilo, M.: Transformations of
nutrients (N, P, Si) in the turbidity maximum zone of the Seine estuary and
export to the sea, Estuar. Coast. Shelf Sci., 90, 129–141, 2010.
Gaye, B., Nagel, B., Dähnke, K., Rixen, T., and Emeis, K. C.: Evidence
of parallel denitrification and nitrite oxidation in the ODZ of the Arabian
Sea from paired stable isotopes of nitrate and nitrite Global Biogeochem.
Cy., 27, 1–13, https://doi.org/10.1002/2011GB004115, 2013.
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.
Granger, J. and Wankel, S. D.: Isotopic overprinting of nitrification on
denitrification as a ubiquitous and unifying feature of environmental
nitrogen cycling, P. Natl. Acad. Sci. USA, 113, E6391–E6400, https://doi.org/10.1073/pnas.1601383113, 2016.
Granger, J., Sigman, D. M., Needoba, J. A., and Harrison, P. J.: Coupled
nitrogen and oxygen isotope fractionation of nitrate during assimilation by
cultures of marine phytoplankton, Limnol. Oceanogr., 49, 1763–1773,
2004.
Granger, J., Prokopenko, M. G., Mordy, C. W., and Sigman, D. M.: The
proportion of remineralized nitrate on the ice-covered eastern Bering Sea
shelf evidenced from the oxygen isotope ratio of nitrate, Global
Biogeochem. Cy., 27, 962–971, https://doi.org/10.1002/gbc.20075, 2013.
Hansen, H. P. and Koroleff, F.: Determination of nutrients, in: Methods of
Seawater Analysis, edited by: Grasshoff, K., Kremling, K., and Ehrhardt, M., Wiley-VCH Verlag GmbH, 159–228, https://doi.org/10.1002/9783527613984.ch10, 1999.
Hoch, M. P., Fogel, M. L., and Kirchman, D. L.: Isotope fractionation
associated with ammonium uptake by a marine bacterium, Limnol.
Oceanogr., 37, 1447–1459, https://doi.org/10.4319/lo.1992.37.7.1447,
1992.
Hofmann, J., Behrendt, H., Gilbert, A., Janssen, R., Kannen, A., Kappenberg,
J., Lenhart, H., Lise, W., Nunneri, C., and Windhorst, W.:
Catchment – coastal zone interaction based upon scenario and model analysis:
Elbe and the German Bight case study, Reg. Environ. Change, 5,
54–81, https://doi.org/10.1007/s10113-004-0082-y, 2005.
Islam, M. J., Jang, C., Eum, J., Jung, S.-M., Shin, M.-S., Lee, Y., Choi,
Y., and Kim, B.: C : N : P stoichiometry of particulate and dissolved organic
matter in river waters and changes during decomposition, J. Ecol. Environ., 43, 4, https://doi.org/10.1186/s41610-018-0101-4, 2019.
Jacob, J., Sanders, T., and Dähnke, K.: Nitrite consumption and
associated isotope changes during a river flood event, Biogeosciences, 13,
5649–5659, https://doi.org/10.5194/bg-13-5649-2016, 2016.
Jacob, J., Nowka, B., Merten, V., Sanders, T., Spieck, E., and Dähnke,
K.: Oxidation kinetics and inverse isotope effect of marine
nitrite-oxidizing isolates, Aquat. Microb. Ecol., 80, 289–300, https://doi.org/10.3354/ame01859, 2018.
Johannsen, A., Dähnke, K., and Emeis, K.: Isotopic composition of
nitrate in five German rivers discharging into the North Sea, Org.
Geochem., 39, 1678–1689, 2008.
Kappenberg, J. and Fanger, H.-U.: Sedimenttransportgeschehen in der
tidebeeinflussten Elbe, der Deutschen Bucht und in der Nordsee, GKKS Forschungszentrum GmbH,
ISSN 0344-9629, 2007.
Kendall, C.: Tracing nitrogen sources and cycling in catchments, in: Isotope
Tracers in Catchment Hydrology, edited by: Kendall, C. and McDonnell, J.
J., Elsevier, Amsterdam, 521–576, https://doi.org/10.1016/B978-0-444-81546-0.50023-9, 1998.
Klawonn, I., Bonaglia, S., Brüchert, V., and Ploug, H.: Aerobic and
anaerobic nitrogen transformation processes in N2-fixing cyanobacterial
aggregates, ISME J., 9, 1456–1466, https://doi.org/10.1038/ismej.2014.232, 2015.
Liu, T., Xia, X., Liu, S., Mou, X., and Qiu, Y.: Acceleration of
Denitrification in Turbid Rivers Due to Denitrification Occurring on
Suspended Sediment in Oxic Waters, Environ. Sci. Technol.,
47, 4053–4061, https://doi.org/10.1021/es304504m, 2013.
Lozán, J. L. and Kausch, H.: Warnsignale aus Flüssen und Ästuaren, Parey Berlin, ISBN: 978-3980966870, 1996.
Mariotti, A., Germon, J. C., Hubert, P., Kaiser, P., Letolle, R., Tardieux,
A., and Tardieux, P.: Experimental-Determination of Nitrogen Kinetic Isotope
Fractionation – Some Principles – Illustration for the Denitrification and
Nitrification Processes, Plant Soil, 62, 413–430, https://doi.org/10.1007/BF02374138,
1981.
Mariotti, A., Leclerc, A., and Germon, J. C.: Nitrogen isotope fractionation
associated with the NO
Martin, T. S., Primeau, F., and Casciotti, K. L.: Modeling oceanic nitrate
and nitrite concentrations and isotopes using a 3-D inverse N cycle model,
Biogeosciences, 16, 347–367, https://doi.org/10.5194/bg-16-347-2019, 2019.
Martiny, A. C., Vrugt, J. A., and Lomas, M. W.: Concentrations and ratios of
particulate organic carbon, nitrogen, and phosphorus in the global ocean,
Sci. Data, 1, 140048, https://doi.org/10.1038/sdata.2014.48, 2014.
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, 2005.
Meincke, M., Bock, E., Kastrau, D., and Kroneck, P. M. H.: Nitrite
oxidoreductase from Nitrobacter hamburgensis: redox centers and their
catalytic role, Arch. Microbiol., 158, 127–131, https://doi.org/10.1007/BF00245215,
1992.
Middelburg, J. J. (Ed.): Organic Matter is more than CH2O, in: Marine Carbon
Biogeochemistry: A Primer for Earth System Scientists, Springer International Publishing, Springer, Cham, 107–118, ISBN: 978-3-030-10822-9, https://doi.org/10.1007/978-3-030-10822-9_6, 2019.
Middelburg, J. J. and Herman, P. M. J.: Organic matter processing in tidal
estuaries, Mar. Chem., 106, 127–147, 2007.
Middelburg, J. J. and Nieuwenhuize, J.: Nitrogen isotope tracing of
dissolved inorganic nitrogen behaviour in tidal estuaries, Estuar. Coast. Shelf Sci., 53, 385–391, 2001.
Möbius, J.: Isotope fractionation during nitrogen remineralization
(ammonification): Implications for nitrogen isotope biogeochemistry,
Geochim. Cosmochim. Ac., 105, 422–432,
https://doi.org/10.1016/j.gca.2012.11.048, 2013.
Möbius, J., Lahajnar, N., and Emeis, K. C.: Diagenetic control of
nitrogen isotope ratios in Holocene sapropels and recent sediments from the
Eastern Mediterranean Sea, Biogeosciences, 7, 3901–3914, https://doi.org/10.5194/bg-7-3901-2010, 2010.
OSPAR Commission: Second OSPAR Integrated Report on the Eutrophication
Status of the OSPAR Maritime Area, Eutrophication Series, OSPAR Comission,
London, United Kingdom, ISBN: 978-1-906840-13-6, 2008.
Pastuszak, M., Witek, Z., Nagel, K., Wielgat, M., and Grelowski, A.: Role of
the Oder estuary (southern Baltic) in transformation of the riverine
nutrient loads, J. Mar. Syst., 57, 30–54, 2005.
Pätsch, J., Serna, A., Dähnke, K., Schlarbaum, T., Johannsen, A.,
and Emeis, K. C.: Nitrogen cycling in the German Bight (SE North Sea) –
Clues from modelling stable nitrogen isotopes, Cont. Shelf Res.,
30, 203–213, https://doi.org/10.1016/j.csr.2009.11.003, 2010.
Pennock, J. R., Velinsky, D. J., Ludlam, J. M., Sharp, J. H., and Fogel, M.
L.: Isotopic fractionation of ammonium and nitrate during uptake by
Skeletonema costatum: Implications for δ15N dynamics under bloom
conditions, Limnol. Oceanogr., 41, 451–459,
https://doi.org/10.4319/lo.1996.41.3.0451, 1996.
Petersen, W., Schroeder, F., and Bockelmann, F.-D.: FerryBox – Application
of continuous water quality observations along transects in the North Sea,
Ocean Dynam., 61, 1541–1554, https://doi.org/10.1007/s10236-011-0445-0, 2011.
Quick, A. M., Reeder, W. J., Farrell, T. B., Tonina, D., Feris, K. P., and
Benner, S. G.: Nitrous oxide from streams and rivers: A review of primary
biogeochemical pathways and environmental variables, Earth-Sci. Rev.,
191, 224–262, https://doi.org/10.1016/j.earscirev.2019.02.021, 2019.
Radach, G. and Pätsch, J.: Variability of continental riverine
freshwater and nutrient inputs into the North Sea for the years 1977–2000
and its consequences for the assessment of eutrophication, Estuar.
Coast., 30, 66–81, 2007.
Redfield, A. C., Ketchum, B. H., and Richards, F. A.: The influence of
organisms on the composition of sea-water, in: The Sea, edited by: Hill, M. N., Vol. 2, Interscience Publishers, New York, 26–77,
ISBN: 9780674017283, 1963.
Sanders, T. and Laanbroek, H. J.: The distribution of sediment and water
column nitrification potential in the hyper-turbid Ems estuary, Aquat.
Sci., 80, 33, https://doi.org/10.1007/s00027-018-0584-1, 2018.
Sanders, T., Schöl, A., and Dähnke, K.: Hot Spots of Nitrification
in the Elbe Estuary and Their Impact on Nitrate Regeneration, Estuar.
Coast., 41, 128–138, https://doi.org/10.1007/s12237-017-0264-8, 2018.
Santoro, A. E. and Casciotti, K. L.: Enrichment and characterization of
ammonia-oxidizing archaea from the open ocean: phylogeny, physiology and
stable isotope fractionation, ISME J., 5, 1796–1808, https://doi.org/10.1038/ismej.2011.58, 2011.
Schlarbaum, T., Dähnke, K., and Emeis, K.: Turnover of combined
dissolved organic nitrogen and ammonium in the Elbe estuary/NW Europe:
Results of nitrogen isotope investigations, Mar. Chem., 119, 91–107, https://doi.org/10.1016/j.marchem.2009.12.007, 2010.
Schöl, A., Hein, B., Wyrwa, J., and Kiresch, V.: Modelling water quality
in the Elbe and its estuary – Large scale and long term applications with
focus on the oxygen budget of the estuary, Die Küste, 81, 203–232,
2014.
Schröder, F., Wiltshire, K. H., Klages, D., Mathieu, B., and Knauth, H.-D.: Nitrogen and oxygen processes in sediments of the Elbe estuary, Archiv. Hydrobiol., 110, 311–328, 1996.
Sebilo, M., Billen, G., Mayer, B., Billiou, D., Grably, M., Garnier, J., and
Mariotti, A.: Assessing nitrification and denitrification in the seine river
and estuary using chemical and isotopic techniques, Ecosystems, 9, 564–577,
2006.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M.,
and Bohlke, J. K.: A bacterial method for the nitrogen isotopic analysis of
nitrate in seawater and freshwater, Anal. Chem., 73, 4145–4153,
2001.
Sigman, D. M., DiFiore, P. J., Hain, M. P., Deutsch, C., Wang, Y., Karl, D.
M., Knapp, A. N., Lehmann, M. F., and Pantoja, S.: The dual isotopes of deep
nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen,
Deep-Sea Res. Pt. I, 56, 1419–1439, https://doi.org/10.1016/j.dsr.2009.04.007, 2009.
Spieckermann, M. J.: Controls of Oxygen Consumption of Sediments in the
Upper Elbe Estuary, University of Hamburg, Germany, 96 pp., https://ediss.sub.uni-hamburg.de/handle/ediss/9129 (last access: 10 August 2022), 2021.
Stephens, B. M., Wankel, S. D., Beman, J. M., Rabines, A. J., Allen, A. E.,
and Aluwihare, L. I.: Euphotic zone nitrification in the California Current
Ecosystem, Limnol. Oceanogr., 65, 790–806,
https://doi.org/10.1002/lno.11348, 2020.
Umweltbundesamt, 2021: Flusseinträge und direkte Einträge in die
Nordsee,
https://www.umweltbundesamt.de/daten/, last access: 8 October 2021.
van Beusekom, J. E. E. and de Jonge, V. N.: Retention of phosphorus and
nitrogen in the Ems estuary, Estuaries, 21, 527–539, 1998.
Voynova, Y. G., Brix, H., Petersen, W., Weigelt-Krenz, S., and Scharfe, M.:
Extreme flood impact on estuarine and coastal biogeochemistry: the 2013 Elbe
flood, Biogeosciences, 14, 541–557, https://doi.org/10.5194/bg-14-541-2017, 2017.
Wada, E. and Hattori, A.: Nitrogen isotope effects in the assimilation of
inorganic nitrogenous compounds by marine diatoms, Geomicrobiology, 1,
85–101, 1978.
Wankel, S. D., Kendall, C., Francis, C. A., and Paytan, A.: Nitrogen sources
and cycling in the San Francisco Bay Estuary: A nitrate dual isotopic
composition approach, Limnol. Oceanogr., 51, 1654–1664, 2006.
Wankel, S. D., Kendall, C., Pennington, J. T., Chavez, F. P., and Paytan,
A.: Nitrification in the euphotic zone as evidenced by nitrate dual isotopic
composition: Observations from Monterey Bay, California,
Global Biogeochem. Cy., 21, GB2009, https://doi.org/10.1029/2006GB002723, 2007.
Waser, N. A. D., Harrison, P. J., Nielsen, B., Calvert, S. E., and Turpin,
D. H.: Nitrogen isotope fractionation during the uptake and assimilation of
nitrate, nitrite, ammonium, and urea by a marine diatom, Limnol.
Oceanogr., 43, 215–224, https://doi.org/10.4319/lo.1998.43.2.0215, 1998.
York, J. K., Tomasky, G., Valiela, I., and Repeta, D. J.: Stable isotopic
detection of ammonium and nitrate assimilation by phytoplankton in the
Waquoit Bay estuarine system, Limnol. Oceanogr., 52, 144–155, 2007.
Zhang, L., Altabet, M. A., Wu, T. X., and Hadas, O.: Sensitive measurement
of NH
Short summary
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.
Nitrogen is an important macronutrient that fuels algal production in rivers and coastal...
Altmetrics
Final-revised paper
Preprint