Articles | Volume 10, issue 1
https://doi.org/10.5194/bg-10-23-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-10-23-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
04 Jan 2013
Research article |
| 04 Jan 2013
Organic carbon and nitrogen export from a tropical dam-impacted floodplain system
R. Zurbrügg
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, 8092 Zurich, Switzerland
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Surface Waters – Research and Management, Seestrasse 79, 6047 Kastanienbaum, Switzerland
S. Suter
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, 8092 Zurich, Switzerland
M. F. Lehmann
Institute of Environmental Geosciences, University of Basel, Bernoullistrasse 30, 4056 Basel, Switzerland
B. Wehrli
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, 8092 Zurich, Switzerland
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Surface Waters – Research and Management, Seestrasse 79, 6047 Kastanienbaum, Switzerland
D. B. Senn
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, 8092 Zurich, Switzerland
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Surface Waters – Research and Management, Seestrasse 79, 6047 Kastanienbaum, Switzerland
Related authors
No articles found.
Carolina F.M. de Carvalho, Moritz F. Lehmann, and Sarah G. Pati
EGUsphere, https://doi.org/10.5194/egusphere-2025-1193, https://doi.org/10.5194/egusphere-2025-1193, 2025
Short summary
Short summary
Using O2 stable isotope analysis, we determined the isotopic fractionation of biological O2 consumption by 10 flavin-dependent and 6 metalloenzymes. Metalloenzymes displayed a narrower range and lower values of isotopic fractionation than flavin-dependent enzymes. This work expands our understanding of the variability of oxygen isotopic fractionation at the enzyme level, improving the ability to study O2 dynamics from molecular to ecosystem scales.
Guangyi Su, Julie Tolu, Clemens Glombitza, Jakob Zopfi, Moritz F. Lehmann, Mark A. Lever, and Carsten J. Schubert
EGUsphere, https://doi.org/10.5194/egusphere-2025-437, https://doi.org/10.5194/egusphere-2025-437, 2025
Short summary
Short summary
In Lake Geneva, we studied how different types of organic matter affect methane production. Despite varying sources—like algae and land-based materials, both deep and delta areas are significant methane sources and methane was mainly produced through CO2 reduction. Surprisingly, the origin of organic matter didn’t strongly influence methane production rates or pathways. Our findings highlight the need to better understand microbial processes to predict methane emissions from lakes.
Owen A. Sherwood, Samuel H. Davin, Nadine Lehmann, Carolyn Buchwald, Evan N. Edinger, Moritz F. Lehmann, and Markus Kienast
Biogeosciences, 18, 4491–4510, https://doi.org/10.5194/bg-18-4491-2021, https://doi.org/10.5194/bg-18-4491-2021, 2021
Short summary
Short summary
Pacific water flowing eastward through the Canadian Arctic plays an important role in redistributing nutrients to the northwest Atlantic Ocean. Using samples collected from northern Baffin Bay to the southern Labrador Shelf, we show that stable isotopic ratios in seawater nitrate reflect the fraction of Pacific to Atlantic water. These results provide a new framework for interpreting patterns of nitrogen isotopic variability recorded in modern and archival organic materials in the region.
Sigrid van Grinsven, Kirsten Oswald, Bernhard Wehrli, Corinne Jegge, Jakob Zopfi, Moritz F. Lehmann, and Carsten J. Schubert
Biogeosciences, 18, 3087–3101, https://doi.org/10.5194/bg-18-3087-2021, https://doi.org/10.5194/bg-18-3087-2021, 2021
Short summary
Short summary
Lake Lovojärvi is a nutrient-rich lake with high amounts of methane at the bottom, but little near the top. Methane comes from the sediment and rises up through the water but is consumed by microorganisms along the way. They use oxygen if available, but in deeper water layers, no oxygen was present. There, nitrite, iron and humic substances were used, besides a collaboration between photosynthetic organisms and methane consumers, in which the first produced oxygen for the latter.
Yunhua Chang, Yan-Lin Zhang, Sawaeng Kawichai, Qian Wang, Martin Van Damme, Lieven Clarisse, Tippawan Prapamontol, and Moritz F. Lehmann
Atmos. Chem. Phys., 21, 7187–7198, https://doi.org/10.5194/acp-21-7187-2021, https://doi.org/10.5194/acp-21-7187-2021, 2021
Short summary
Short summary
In this study, we integrated satellite constraints on atmospheric NH3 levels and fire intensity, discrete NH3 concentration measurement, and N isotopic analysis of NH3 in order to assess the regional-scale contribution of biomass burning to ambient atmospheric NH3 in the heartland of Southeast Asia. The combined approach provides a valuable cross-validation framework for source apportioning of NH3 in the lower atmosphere and will thus help to ameliorate predictions of biomass burning emissions.
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.
Adeline N. Y. Cojean, Jakob Zopfi, Alan Gerster, Claudia Frey, Fabio Lepori, and Moritz F. Lehmann
Biogeosciences, 16, 4705–4718, https://doi.org/10.5194/bg-16-4705-2019, https://doi.org/10.5194/bg-16-4705-2019, 2019
Short summary
Short summary
Our results demonstrate the importance of oxygen in regulating the fate of nitrogen (N) in the sediments of Lake Lugano south basin, Switzerland. Hence, our study suggests that, by changing oxygen concentration in bottom waters, the seasonal water column turnover may significantly regulate the partitioning between N removal and N recycling in surface sediments, and it is likely that a similar pattern can be expected in a wide range of environments.
Yunhua Chang, Yan-Lin Zhang, Jiarong Li, Chongguo Tian, Linlin Song, Xiaoyao Zhai, Wenqi Zhang, Tong Huang, Yu-Chi Lin, Chao Zhu, Yunting Fang, Moritz F. Lehmann, and Jianmin Chen
Atmos. Chem. Phys., 19, 12221–12234, https://doi.org/10.5194/acp-19-12221-2019, https://doi.org/10.5194/acp-19-12221-2019, 2019
Short summary
Short summary
The present work underscores the value of cloud water dissolved inorganic nitrogen isotopes as carriers of quantitative information on regional NOx and NH3 emissions. It sheds light on the origin and production pathways of nitrogenous species in clouds and emphasizes the importance of biomass-burning-derived nitrogenous species as cloud condensation nuclei in China’s troposphere. Moreover, it highlights the rapid evolution of NOx emissions in China.
Haoyi Yao, Wei-Li Hong, Giuliana Panieri, Simone Sauer, Marta E. Torres, Moritz F. Lehmann, Friederike Gründger, and Helge Niemann
Biogeosciences, 16, 2221–2232, https://doi.org/10.5194/bg-16-2221-2019, https://doi.org/10.5194/bg-16-2221-2019, 2019
Short summary
Short summary
How methane is transported in the sediment is important for the microbial community living on methane. Here we report an observation of a mini-fracture that facilitates the advective gas transport of methane in the sediment, compared to the diffusive fluid transport without a fracture. We found contrasting bio-geochemical signals in these different transport modes. This finding can help to fill the gap in the fracture network system in modulating methane dynamics in surface sediments.
Martin Ley, Moritz F. Lehmann, Pascal A. Niklaus, and Jörg Luster
Biogeosciences, 15, 7043–7057, https://doi.org/10.5194/bg-15-7043-2018, https://doi.org/10.5194/bg-15-7043-2018, 2018
Short summary
Short summary
Our laboratory study shows how microhabitat formation linked to soil aggregates, litter accumulation and plant soil interactions affects conditions under which
hot momentsof enhanced N2O emissions from floodplain soils during the drying phase after saturation occur. Larger aggregate size led to higher integrated flux rates when soil was unamended or mixed with leaf litter, whereas planting with willow significantly reduced emissions. Also, emission time patterns differed among the treatments.
Yunhua Chang, Yanlin Zhang, Chongguo Tian, Shichun Zhang, Xiaoyan Ma, Fang Cao, Xiaoyan Liu, Wenqi Zhang, Thomas Kuhn, and Moritz F. Lehmann
Atmos. Chem. Phys., 18, 11647–11661, https://doi.org/10.5194/acp-18-11647-2018, https://doi.org/10.5194/acp-18-11647-2018, 2018
Short summary
Short summary
We demonstrate that it is imperative that future studies, making use of isotope mixing models to gain conclusive constraints on the source partitioning of atmospheric NOx, consider this N isotope fractionation. Future assessments of NOx emissions in China (and elsewhere) should involve simultaneous δ15N and δ18O measurements of atmospheric nitrate and NOx at high spatiotemporal resolution, allowing former N-isotope-based NOx source partitioning estimates to be reevaluated more quantitatively.
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
Short summary
Short summary
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.
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.
C. V. Freymond, C. B. Wenk, C. H. Frame, and M. F. Lehmann
Biogeosciences, 10, 8373–8383, https://doi.org/10.5194/bg-10-8373-2013, https://doi.org/10.5194/bg-10-8373-2013, 2013
M. Alkhatib, P. A. del Giorgio, Y. Gelinas, and M. F. Lehmann
Biogeosciences, 10, 7609–7622, https://doi.org/10.5194/bg-10-7609-2013, https://doi.org/10.5194/bg-10-7609-2013, 2013
Related subject area
Biogeochemistry: Rivers & Streams
Temporal dynamics and environmental controls of carbon dioxide and methane fluxes measured by the eddy covariance method over a boreal river
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
Riverine dissolved organic matter responds to alterations differently in two distinct hydrological regimes from Northern Spain
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
Nitrogen isotopes reveal a particulate-matter-driven biogeochemical reactor in a temperate estuary
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
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.
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.
Selin Kubilay, Edurne Estévez, José Barquín Ortiz, and Gabriel Singer
EGUsphere, https://doi.org/10.5194/egusphere-2024-2772, https://doi.org/10.5194/egusphere-2024-2772, 2024
Short summary
Short summary
Here, we studied how dams change the natural flow of rivers and their organic matter dynamics in Northern Spain. We found that in Atlantic rivers, natural rivers showed a higher turnover of organic material quality, which we believe is due to the interference of dams with the natural seasonal flow patterns. This suggests that Mediterranean rivers might be more resilient to flow regime alterations while Atlantic rivers lose their natural variability in organic material.
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.
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
Short summary
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.
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
Aalto, R., Maurice-Bourgoin, L., Dunne, T., Montgomery, D. R., Nittrouer, C. A., and Guyot, J. L.: Episodic sediment accumulation on Amazonian flood plains influenced by El Niño/Southern Oscillation, Nature, 425, 493–497, https://doi.org/10.1038/nature02002, 2003.
Alin, S. R., Aalto, R., Goni, M. A., Richey, J. E., and Dietrich, W. E.: Biogeochemical characterization of carbon sources in the strickland and fly rivers, Papua New Guinea, J. Geophys. Res.-Earth Surface, 113, F01s05, https://doi.org/10.1029/2006jf000625, 2008.
Alvarez-Cobelas, M., Angeler, D. G., Sanchez-Carrillo, S., and Almendros, G.: A worldwide view of organic carbon export from catchments, Biogeochemistry, 107, 275–293, https://doi.org/10.1007/s10533-010-9553-z, 2012.
Aufdenkampe, A. K., Mayorga, E., Hedges, J. I., Llerena, C., Quay, P. D., Gudeman, J., Krusche, A. V., and Richey, J. E.: Organic matter in the Peruvian headwaters of the Amazon: Compositional evolution from the Andes to the lowland Amazon mainstem, Org. Geochem., 38, 337–364, https://doi.org/10.1016/j.orggeochem.2006.06.003, 2007.
Battin, T. J., Luyssaert, S., Kaplan, L. A., Aufdenkampe, A. K., Richter, A., and Tranvik, L. J.: The boundless carbon cycle, Nature Geosci., 2, 598–600, https://doi.org/10.1038/ngeo618, 2009.
Berman, T. and Bronk, D. A.: Dissolved organic nitrogen: a dynamic participant in aquatic ecosystems, Aquat. Microb. Ecol., 31, 279–305, 2003.
Bernardes, M. C., Martinelli, L. A., Krusche, A. V., Gudeman, J., Moreira, M., Victoria, R. L., Ometto, J., Ballester, M. V. R., Aufdenkampe, A. K., Richey, J. E., and Hedges, J. I.: Riverine organic matter composition as a function of land use changes, Southwest Amazon, Ecol. Appl., 14, S263–S279, 2004.
Bouillon, S., Dehairs, F., Schiettecatte, L. S., and Borges, A. V.: Biogeochemistry of the Tana estuary and delta (northern Kenya), Limnol. Oceanogr., 52, 46–59, 2007.
Bouillon, S., Abril, G., Borges, A. V., Dehairs, F., Govers, G., Hughes, H. J.,Merckx, R., Meysman, F. J. R., Nyunja, J., Osburn, C., and Middelburg, J. J.: Distribution, origin and cycling of carbon in the Tana River (Kenya): a dry season basin-scale survey from headwaters to the delta, Biogeosciences, 6, 2475–2493, https://doi.org/10.5194/bg-6-2475-2009, 2009.
Bourbonnais, A., Lehmann, M. F., Waniek, J. J., and Schulz-Bull, D. E.: Nitrate isotope anomalies reflect N2 fixation in the Azores Front region (subtropical NE Atlantic), J. Geophys. Res.-Oceans, 114, https://doi.org/10.1029/2007jc004617, 2009.
Braman, R. S. and Hendrix, S. A.: Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(III) reduction with chemiluminescence detection, Anal. Chem., 61, 2715–2718, 1989.
Bronk, D. A., Lomas, M. W., Glibert, P. M., Schukert, K. J., and Sanderson, M. P.: Total dissolved nitrogen analysis: comparisons between the persulfate, UV and high temperature oxidation methods, Mar. Chem., 69, 163–178, 2000.
Casciotti, K. L., Sigman, D. M., Hastings, M. G., Böhlke, J. K., and Hilkert, A.: Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method, Anal. Chem., 74, 4905–4912, 2002.
Chen, F. J. and Jia, G. D.: Spatial and seasonal variations in $\delta ^{13}$C and δ15N of particulate organic matter in a dam-controlled subtropical river, River Res. Appl., 25, 1169–1176, https://doi.org/10.1002/rra.1225, 2009.
Chen, H. and Zheng, B. H.: Characterizing natural dissolved organic matter in a freshly submerged catchment (Three Gorges Dam, China) using UV absorption, fluorescence spectroscopy and PARAFAC, Water Sci. Technol., 65, 962–969, https://doi.org/10.2166/wst.2012.939, 2012.
Chen, W., Westerhoff, P., Leenheer, J. A., and Booksh, K.: Fluorescence excitation-emission matrix regional integration to quantify spectra for dissolved organic matter, Environ. Sci. Technol., 37, 5701–5710, https://doi.org/10.1021/es034354c, 2003.
Cleveland, C. C., Townsend, A. R., Schimel, D. S., Fisher, H., Howarth, R. W., Hedin, L. O., Perakis, S. S., Latty, E. F., Von Fischer, J. C., Elseroad, A., and Wasson, M. F.: Global patterns of terrestrial biological nitrogen (N2) fixation in natural ecosystems, Global Biogeochem. Cy., 13, 623–645, https://doi.org/10.1029/1999gb900014, 1999.
Coble, P. G.: Characterization of marine and terrestrial DOM in seawater using excitation emission matrix spectroscopy, Mar. Chem., 51, 325–346, 1996.
Cory, R. M., Miller, M. P., McKnight, D. M., Guerard, J. J., and Miller, P. L.: Effect of instrument-specific response on the analysis of fulvic acid fluorescence spectra, Limnol. Oceanogr.-Meth., 8, 67–78, 2010.
Cotner, J. B., Montoya, J. V., Roelke, D. L., and Winemiller, K. O.: Seasonally variable riverine production in the Venezuelan llanos, J. North Am. Benthol. Soc., 25, 171–184, https://doi.org/10.1899/0887-3593(2006)25[171:SVRPIT]2.0.CO;2, 2006.
Ellenbroek, G. A.: Ecology and productivity of an African wetland system. Geobotany 9, Dr. W. Junk, Dordrecht, 267 pp., 1987.
Ellis, E. E., Richey, J. E., Aufdenkampe, A. K., Krusche, A. V., Quay, P. D., Salimon, C., and da Cunha, H. B.: Factors controlling water-column respiration in rivers of the central and southwestern Amazon Basin, Limnol. Oceanogr., 57, 527–540, https://doi.org/10.4319/lo.2012.57.2.0527, 2012.
Galy, V. and Eglinton, T.: Protracted storage of biospheric carbon in the Ganges-Brahmaputra basin, Nature Geosci., 4, 843–847, https://doi.org/10.1038/ngeo1293, 2011.
Grasshoff, K., Kremling, K., and Ehrhardt, M.: Methods of Seawater Analysis, Third ed., Wiley-VCH, Weinheim, New York, Chichester Brisbane, Singapore, Tokyo, 632 pp., 1999.
Gu, B. and Alexander, V.: Estimation of N2 fixation based on differences in the natural-abundance of 15N among fresh-water N2-fixing and non-N2-fixing algae, Oecologia, 96, 43–48, 1993.
Hamilton, S. K. and Lewis, W. M.: Stable carbon and nitrogen isotopes in algae and detritus from the Orinoco River floodplain, Venezuela, Geochim. Cosmochim. Ac., 56, 4237–4246, 1992.
Harrison, J. A., Caraco, N., and Seitzinger, S. P.: Global patterns and sources of dissolved organic matter export to the coastal zone: Results from a spatially explicit, global model, Global Biogeochem. Cy., 19, Gb4s04 https://doi.org/10.1029/2005gb002480, 2005.
Hedges, J. I., Mayorga, E., Tsamakis, E., McClain, M. E., Aufdenkampe, A., Quay, P., Richey, J. E., Benner, R., Opsahl, S., Black, B., Pimentel, T., Quintanilla, J., and Maurice, L.: Organic matter in Bolivian tributaries of the Amazon River: A comparison to the lower mainstream, Limnol. Oceanogr., 45, 1449–1466, 2000.
Hoffmann, C. C., Kronvang, B., and Audet, J.: Evaluation of nutrient retention in four restored Danish riparian wetlands, Hydrobiologia, 674, 5–24, https://doi.org/10.1007/s10750-011-0734-0, 2011.
Hunsinger, G. B., Mitra, S., Findlay, S. E. G., and Fischer, D. T.: Wetland-driven shifts in suspended particulate organic matter composition of the Hudson River estuary, New York, Limnol. Oceanogr., 55, 1653–1667, 2010.
Ishii, S. K. L. and Boyer, T. H.: Behavior of reoccurring PARAFAC components in fluorescent dissolved organic matter in natural and engineered systems: A critical review, Environ. Sci. Technol., 46, 2006–2017, https://doi.org/10.1021/es2043504, 2012.
Johnson, M. S., Lehmann, J., Selva, E. C., Abdo, M., Riha, S., and Couto, E. G.: Organic carbon fluxes within and streamwater exports from headwater catchments in the southern Amazon, Hydrol. Process., 20, 2599–2614, https://doi.org/10.1002/hyp.6218, 2006.
Johnson, M. S., Couto, E. G., Abdo, M., and Lehmann, J.: Fluorescence index as an indicator of dissolved organic carbon quality in hydrologic flowpaths of forested tropical watersheds, Biogeochemistry, 105, 149–157, https://doi.org/10.1007/s10533-011-9595-x, 2011.
Kern, J. and Darwich, A.: The role of periphytic N2 fixation for stands of macrophytes in the whitewater floodplain (varzea), Amazoniana-Limnologia Et Oecologia Regionalis Systemae Fluminis Amazonas, 17, 361–375, 2003.
Knapp, A. N., Sigman, D. M., and Lipschultz, F.: N isotopic composition of dissolved organic nitrogen and nitrate at the Bermuda Atlantic time-series study site, Global Biogeochem. Cy., 19, GB1018, https://doi.org/10.1029/2004gb002320, 2005.
Kunz, M. J., Wüest, A., Wehrli, B., Landert, J., and Senn, D. B.: Impact of a large tropical reservoir on riverine transport of sediment, carbon, and nutrients to downstream wetlands, Water Resour. Res., 47, W12531, https://doi.org/10.1029/2011WR010996, 2011.
Lakowicz, J. R.: Principles of Fluorescence Spectroscopy, 3rd Edn., Springer, New York, 954 pp., 2006.
Martinelli, L. A., Victoria, R. L., Trivelin, P. C. O., Devol, A. H., and Richey, J. E.: N-15 natural abundance in plants of the Amazon River floodplain and potential atmospheric N2 fixation, Oecologia, 90, 591–596, 1992.
Mayorga, E., Aufdenkampe, A. K., Masiello, C. A., Krusche, A. V., Hedges, J. I., Quay, P. D., Richey, J. E., and Brown, T. A.: Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers, Nature, 436, 538–541, https://doi.org/10.1038/nature03880, 2005.
Mayorga, E., Seitzinger, S. P., Harrison, J. A., Dumont, E., Beusen, A. H. W., Bouwman, A. F., Fekete, B. M., Kroeze, C., and Van Drecht, G.: Global Nutrient Export from WaterSheds 2 (NEWS 2): Model development and implementation, Environ. Modell. Software, 25, 837–853, https://doi.org/10.1016/j.envsoft.2010.01.007, 2010.
McJannet, D., Wallace, J., Keen, R., Hawdon, A., and Kemei, J.: The filtering capacity of a tropical riverine wetland: II. Sediment and nutrient balances, Hydrol. Process., 26, 53–72, https://doi.org/10.1002/hyp.8111, 2012.
McKnight, D. M., Boyer, E. W., Westerhoff, P. K., Doran, P. T., Kulbe, T., and Andersen, D. T.: Spectrofluorometric characterization of dissolved organic matter for indication of precursor organic material and aromaticity, Limnol. Oceanogr., 46, 38–48, 2001.
Meier, P., Wang, H., Milzow, C., and Kinzelbach, W.: Remote sensing for hydrological modeling of seasonal wetlands – Concepts and applications, ESA Living Planet Symposium, 28 June–2 July 2010, Bergen, Norway, 2010,
Miller, M. P. and McKnight, D. M.: Comparison of seasonal changes in fluorescent dissolved organic matter among aquatic lake and stream sites in the Green Lakes Valley, J. Geophys. Res.-Biogeosci., 115, https://doi.org/10.1029/2009jg000985, 2010.
Mitsch, W. J. and Gosselink, J. G.: Wetlands, 4th Edn., John Wiley & Sons Inc., New Jersey, USA, 582 pp., 2007.
Mladenov, N., McKnight, D. M., Wolski, P., and Ramberg, L.: Effects of annual flooding on dissolved organic carbon dynamics within a pristine wetland, the Okavango Delta, Botswana, Wetlands, 25, 622–638, 2005.
Mumba, M., and Thompson, J. R.: Hydrological and ecological impacts of dams on the Kafue Flats floodplain system, southern Zambia, Phys. Chem. Earth, 30, 442–447, 2005.
Munyati, C.: Wetland change detection on the Kafue Flats, Zambia, by classification of a multitemporal remote sensing image dataset, Int. J. Remote Sens., 21, 1787–1806, 2000.
Noe, G. B. and Hupp, C. R.: Retention of riverine sediment and nutrient loads by coastal plain floodplains, Ecosystems, 12, 728–746, https://doi.org/10.1007/s10021-009-9253-5, 2009.
Olde Venterink, H., Wiegman, F., Van der Lee, G. E. M., and Vermaat, J. E.: Role of active floodplains for nutrient retention in the river Rhine, J. Environ. Qual., 32, 1430–1435, 2003.
Petrone, K. C., Fellman, J. B., Hood, E., Donn, M. J., and Grierson, P. F.: The origin and function of dissolved organic matter in agro-urban coastal streams, J. Geophys. Res.-Biogeosci., 116, 13, G01028, https://doi.org/10.1029/2010jg001537, 2011.
Raymond, P. A. and Bauer, J. E.: Riverine export of aged terrestrial organic matter to the North Atlantic Ocean, Nature, 409, 497–500, 2001.
Rejmankova, E., Komarkova, J., and Rejmanek, M.: δ15N as an indicator of N2-fixation by cyanobacterial mats in tropical marshes, Biogeochemistry, 67, 353–368, 2004.
Richey, J. E., Mertes, L. A. K., Dunne, T., Victoria, R. L., Forsberg, B. R., S., T. A. C. N., and E., O.: Sources and routing of the Amazon River flood wave, Global Biogeochem. Cy., 3, 191–204, 1989.
Richey, J. E., Hedges, J. I., Devol, A. H., Quay, P. D., Victoria, R., Martinelli, L., and Forsberg, B. R.: Biogeochemistry of carbon in the Amazon River, Limnol. Oceanogr., 35, 352–371, 1990.
Schlarbaum, T., Dähnke, K., and Emeis, K.: Dissolved and particulate reactive nitrogen in the Elbe River/NW Europe: a 2-yr N-isotope study, Biogeosciences, 8, 3519–3530, https://doi.org/10.5194/bg-8-3519-2011, 2011.
Schwendenmann, L., and Veldkamp, E.: The role of dissolved organic carbon, dissolved organic nitrogen, and dissolved inorganic nitrogen in a tropical wet forest ecosystem, Ecosystems, 8, 339–351, https://doi.org/10.1007/s10021-003-0088-1, 2005.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M., and Böhlke, J. K.: A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater, Anal. Chem., 73, 4145–4153, 2001.
Solórzano, L. and Sharp, J. H.: Determination of total dissolved nitrogen in natural waters, Limnol. Oceanogr., 25, 751–754, 1980.
Spencer, R. G. M., Hernes, P. J., Ruf, R., Baker, A., Dyda, R. Y., Stubbins, A., and Six, J.: Temporal controls on dissolved organic matter and lignin biogeochemistry in a pristine tropical river, Democratic Republic of Congo, J. Geophys. Res.-Biogeosci., 115, G03013, https://doi.org/10.1029/2009jg001180, 2010.
Stedmon, C. A., Markager, S., and Bro, R.: Tracing dissolved organic matter in aquatic environments using a new approach to fluorescence spectroscopy, Mar. Chem., 82, 239–254, https://doi.org/10.1016/s0304-4203(03)00072-0, 2003.
Stedmon, C. A., and Markager, S.: Resolving the variability in dissolved organic matter fluorescence in a temperate estuary and its catchment using PARAFAC analysis, Limnol. Oceanogr., 50, 686–697, 2005.
Stedmon, C. A. and Bro, R.: Characterizing dissolved organic matter fluorescence with parallel factor analysis: a tutorial, Limnol. Oceanogr.-Meth., 6, 572–579, 2008.
Tamooh, F., Van den Meersche, K., Meysman, F., Marwick, T. R., Borges, A. V., Merckx, R., Dehairs, F., Schmidt, S., Nyunja, J., and Bouillon, S.: Distribution and origin of suspended matter and organic carbon pools in the Tana River Basin, Kenya, Biogeosciences, 9, 2905–2920, https://doi.org/10.5194/bg-9-2905-2012, 2012.
Tremblay, L. and Benner, R.: Organic matter diagenesis and bacterial contributions to detrital carbon and nitrogen in the Amazon River system, Limnol. Oceanogr., 54, 681–691, 2009.
Wamulume, J., Landert, J., Zurbrügg, R., Nyambe, I., Wehrli, B., and Senn, D. B.: Exploring the hydrology and biogeochemistry of the dam-impacted Kafue River and Kafue Flats (Zambia), Phys. Chem. Earth, 36, 775–788, https://doi.org/10.1016/j.pce.2011.07.049, 2011.
Waterloo, M. J., Oliveira, S. M., Drucker, D. P., Nobre, A. D., Cuartas, L. A., Hodnett, M. G., Langedijk, I., Jans, W. W. P., Tomasella, J., de Araujo, A. C., Pimentel, T. P., and Estrada, J. C. M.: Export of organic carbon in run-off from an Amazonian rainforest blackwater catchment, Hydrol. Process., 20, 2581–2597, https://doi.org/10.1002/hyp.6217, 2006.
Weishaar, J. L., Aiken, G. R., Bergamaschi, B. A., Fram, M. S., Fujii, R., and Mopper, K.: Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon, Environ. Sci. Technol., 37, 4702–4708, https://doi.org/10.1021/es030360x, 2003.
Wiegner, T. N., Tubal, R. L., and MacKenzie, R. A.: Bioavailability and export of dissolved organic matter from a tropical river during base- and stormflow conditions, Limnol. Oceanogr., 54, 1233–1242, https://doi.org/10.4319/lo.2009.54.4.1233, 2009.
Yamashita, Y., Maie, N., Briceno, H., and Jaffé, R.: Optical characterization of dissolved organic matter in tropical rivers of the Guayana Shield, Venezuela, J. Geophys. Res.-Biogeosci., 115, G00f10, https://doi.org/10.1029/2009jg000987, 2010a.
Yamashita, Y., Scinto, L. J., Maie, N., and Jaffé, R.: Dissolved organic matter characteristics across a subtropical wetland's landscape: Application of optical properties in the assessment of environmental dynamics, Ecosystems, 13, 1006–1019, https://doi.org/10.1007/s10021-010-9370-1, 2010b.
Ziegler, S. E. and Brisco, S. L.: Relationships between the isotopic composition of dissolved organic carbon and its bioavailability in contrasting Ozark streams, Hydrobiologia, 513, 153–169, https://doi.org/10.1023/B:hydr.0000018180.54292.47, 2004.
Zurbrügg, R., Wamulume, J., Kamanga, R., Wehrli, B., and Senn, D. B.: River-floodplain exchange and its effects on the fluvial oxygen regime in a large tropical river system (Kafue Flats, Zambia), J. Geophys. Res.-Biogeosci., 117, https://doi.org/10.1029/2011jg001853, 2012.
Altmetrics
Final-revised paper
Preprint