Articles | Volume 13, issue 9
https://doi.org/10.5194/bg-13-2727-2016
© Author(s) 2016. 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-13-2727-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
10 May 2016
Research article |
| 10 May 2016
Along-stream transport and transformation of dissolved organic matter in a large tropical river
University of Liège, Chemical Oceanography Unit, Liège,
Belgium
Cristian R. Teodoru
KU Leuven, Department of Earth and Environmental Sciences, Leuven,
Belgium
Frank C. Nyoni
University of Zambia, Integrated Water Resources Management Centre,
Lusaka, Zambia
Steven Bouillon
KU Leuven, Department of Earth and Environmental Sciences, Leuven,
Belgium
François Darchambeau
University of Liège, Chemical Oceanography Unit, Liège,
Belgium
Philippe Massicotte
Aarhus University, Department of Bioscience, Aarhus, Denmark
Alberto V. Borges
University of Liège, Chemical Oceanography Unit, Liège,
Belgium
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W. Thiery, A. Martynov, F. Darchambeau, J.-P. Descy, P.-D. Plisnier, L. Sushama, and N. P. M. van Lipzig
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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
QUAL-NET, a high temporal-resolution eutrophication model for large hydrographic networks
Diel fluctuations of viscosity-driven riparian inflow affect streamflow DOC concentration
A comprehensive biogeochemical record and annual flux estimates for the Sabaki River (Kenya)
Hydro-ecological controls on dissolved carbon dynamics in groundwater and export to streams in a temperate pine forest
Regional-scale lateral carbon transport and CO2 evasion in temperate stream catchments
Carbon and nutrient export regimes from headwater catchments to downstream reaches
Influence of infrastructure on water quality and greenhouse gas dynamics in urban streams
Hydromorphological restoration stimulates river ecosystem metabolism
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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Nitrogen is an important macronutrient that fuels algal production in rivers and coastal regions. We investigated the production and removal of nitrogen-bearing compounds in the freshwater section of the tidal Elbe Estuary and found that particles in the water column are key for the production and removal of water column nitrate. Using a stable isotope approach, we pinpointed regions where additional removal of nitrate or input from sediments plays an important role in estuarine biogeochemistry.
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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
Camille Minaudo, Florence Curie, Yann Jullian, Nathalie Gassama, and Florentina Moatar
Biogeosciences, 15, 2251–2269, https://doi.org/10.5194/bg-15-2251-2018, https://doi.org/10.5194/bg-15-2251-2018, 2018
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We developed the model QUALity-NETwork (QUAL-NET) to simulate water quality variations in large drainage networks. This model is accurate enough to represent processes occurring over short periods of time such as storm events and helps to fully understand water quality variations in stream networks in the context of climate change and varying human pressures. It was tested on the Loire River and provided good performances and a new understanding of the functioning of the river.
Michael P. Schwab, Julian Klaus, Laurent Pfister, and Markus Weiler
Biogeosciences, 15, 2177–2188, https://doi.org/10.5194/bg-15-2177-2018, https://doi.org/10.5194/bg-15-2177-2018, 2018
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We studied the diel fluctuations of dissolved organic carbon (DOC) concentrations in a small stream in Luxembourg. We identified an increased proportion of DOC from terrestrial sources as responsible for the peaks in DOC in the afternoon. Warmer water temperatures in the riparian zone in the afternoon increased the amount of water flowing towards the stream. Consequently, an increased amount of DOC-rich water from the riparian zone was entering the stream.
Trent R. Marwick, Fredrick Tamooh, Bernard Ogwoka, Alberto V. Borges, François Darchambeau, and Steven Bouillon
Biogeosciences, 15, 1683–1700, https://doi.org/10.5194/bg-15-1683-2018, https://doi.org/10.5194/bg-15-1683-2018, 2018
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A 2-year biogeochemical record provides annual sediment and element flux estimates for the non-dammed Sabaki River, Kenya, establishing a baseline for future research in light of impending construction of the first major upstream reservoir. Over 80 % of material fluxes occur across the wet season, with annual yields comparable to the adjacent, and dammed, Tana River. Observations at low-flow periods suggest large mammalian herbivores may be vectors of terrestrial subsidies to the water column.
Loris Deirmendjian, Denis Loustau, Laurent Augusto, Sébastien Lafont, Christophe Chipeaux, Dominique Poirier, and Gwenaël Abril
Biogeosciences, 15, 669–691, https://doi.org/10.5194/bg-15-669-2018, https://doi.org/10.5194/bg-15-669-2018, 2018
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Carbon leaching to streams represents a very small (~ 2 %) fraction of forest net ecosystem exchange (NEE). Such weak export of carbon from forest ecosystems, at least in temperate regions, is at odds with recent studies that attempt to integrate the contribution of inland waters in the continent carbon budget. Understanding why local and global carbon mass balances strongly diverge on the proportion of land NEE exported to aquatic systems is a major challenge for research in this field.
Katrin Magin, Celia Somlai-Haase, Ralf B. Schäfer, and Andreas Lorke
Biogeosciences, 14, 5003–5014, https://doi.org/10.5194/bg-14-5003-2017, https://doi.org/10.5194/bg-14-5003-2017, 2017
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We analyzed the relationship between terrestrial net primary production (NPP) and the rate at which carbon is exported from catchments in a temperate stream network. The carbon exported by streams and rivers corresponds to 2.7 % of the terrestrial NPP. CO2 evasion and downstream transport contribute about equally to this flux. A review of existing studies suggests that the catchment-specific carbon export varies in a relatively narrow range across different study regions and spatial scales.
Rémi Dupas, Andreas Musolff, James W. Jawitz, P. Suresh C. Rao, Christoph G. Jäger, Jan H. Fleckenstein, Michael Rode, and Dietrich Borchardt
Biogeosciences, 14, 4391–4407, https://doi.org/10.5194/bg-14-4391-2017, https://doi.org/10.5194/bg-14-4391-2017, 2017
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Carbon and nutrient export regimes were analyzed from archetypal headwater catchments to
downstream reaches. In headwater catchments, land use and lithology determine
land-to-stream C, N and P transfer processes. The crucial role of riparian
zones in C, N and P coupling was investigated. In downstream reaches,
point-source contributions and in-stream processes alter C, N and P export
regimes.
Rose M. Smith, Sujay S. Kaushal, Jake J. Beaulieu, Michael J. Pennino, and Claire Welty
Biogeosciences, 14, 2831–2849, https://doi.org/10.5194/bg-14-2831-2017, https://doi.org/10.5194/bg-14-2831-2017, 2017
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Urban streams receive excess nitrogen from numerous sources. We hypothesized that variations in carbon availability and subsurface infrastructure influence emissions of N2O and other greenhouse gases (CH4 and CO2) as excess N is utilized by microbes. We sampled eight streams draining four categories of stormwater and sanitary infrastructure. Dissolved nitrogen concentration was the strongest predictor of CO2 and N2O concentrations, while C : N ratio was the strongest predictor of CH4 in streams.
Benjamin Kupilas, Daniel Hering, Armin W. Lorenz, Christoph Knuth, and Björn Gücker
Biogeosciences, 14, 1989–2002, https://doi.org/10.5194/bg-14-1989-2017, https://doi.org/10.5194/bg-14-1989-2017, 2017
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Modern ecosystem restoration should consider a wide range of environmental characteristics, including functional ones, such as rates and patterns of ecosystem metabolism. We show that hydromorphological river restoration enhanced habitat availability and abundance of macrophytes, promoting river primary productivity and respiration. Incorporating ecosystem functioning into monitoring programs enables a more holistic assessment of river health and a better understanding of restoration effects.
Cited articles
Abril, G., Martinez. J. M., Artigas, L. F., Moreira-Turcq. P., Benedetti, M. F., Vidal, L., Meziane, T., Kin, J. H., Bernardes, M. C., Savoye, N., Deborde, J., Souza, E. L., Albéric, P., Landim de Souza, M. F., and Roland, F.: Amazon River carbon dioxide outgassing fuelled by wetlands, Nature, 505, 395–398, https://doi.org/10.1038/nature12797, 2014.
Amon, R. M. W. and Benner, R.: Bacterial utilization of different size classes of dissolved organic matter, Limnol. Oceanogr., 41, 41–51, 1996.
Battin, T. J.: Dissolved organic matter and its optical properties in a blackwater tributary of the upper Oricono river, Venezuela, Org. Geochem., 28, 561–569, 1998.
Borcard, D., Gillet, F., and Legendre, P.: Numerical ecology with R, Springer New York, New York, 306 pp., https://doi.org/10.1007/978-1-4419-7976-6, 2011.
Borges, A. V., Darchambeau, F., Teodoru, C. R., Marwick, T. R., Tamooh, F., Geeraert, N., Omengo, F. O., Guerin, F., Lambert, T., Morana, C., Okuku, E., and Bouillon, S.: Globally significant greenhouse-gas emissions from african inland waters, Nat. Geosci., 8, 637–642, https://doi.org/10.1038/ngeo2486, 2015a.
Borges, A. V., Abril, G., Darchambeau, F., Teodoru, C. R., Deborde, J., Vidal, L. O., Lambert, T., and Bouillon, S.: Divergent biophysical controls of aquatic CO2 and CH4 in the World's two largest rivers, Sci. Rep., 5, 15614, https://doi.org/10.1038/srep15614, 2015b.
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.
Bouillon, S., Yambélé, A., Gillikin, D. P., Teodoru, C. R., Darchambeau, F., Lambert, T., and Borges, A. V.: Contrasting biogeochemical characteristics of the Oubangui River and tributaries (Congo River basin), Sci. Rep., 4, 1–10, https://doi.org/10.1038/srep05402, 2014.
Brunet, F., Dubois, K., Veizer, J., Nkoue Ndondo, G. R., Ndam Ngoupayou, J. R., Boeglin, J. L., and Probst, J. L.: Terrestrial and fluvial carbon fluxes in a tropical watershed: Nyong basin, Cameroon, Chem. Geol., 265, 563–572, 2009.
Cawley, K. M., Wolski, P., Mladenov, N., and Jaffé, R.: Dissolved organic matter biogeochemistry along a transect of the Okavango delta, Bostwana, Wetlands, 32, 475–486, https://doi.org/10.1007/s13157-012-0281-0, 2012.
Chenje, M.: State of the Environment Zambezi Basin 2000, SADC, IUCN, ZRA, and SARDC, Maseru, Lusaka and Harare, 334 pp., ISBN 978-1-77910-009-2, 2000.
Cole, J. J., Prairie, Y. T., Caraco, N. F., McDowell, W. H., Tranvik, L. J., Striegl, R. G., Duarte, C. M., Kortelainen, P., Downing, J. A., Middelburg, J. J., and Melack, J.: Plumbing the global carbon cycle: integrating inland waters into the terrestrial carbon budget, Ecosystems, 10, 171–184, 2007.
Cory, R. M., McKnight, D. M., Chin, Y. P., Miller, P., and Jaros, C. L.: Chemical characteristics of fulvic acids from Arctic surface waters: Microbial contributions and photochemical transformations, J. Geophys. Res.-Biogeo., 112, G04S51, https://doi.org/10.1029/2006JG000343, 2007.
Davies, B. R., Beilfuss, R. D., and Thoms, M. C.: Cahora Bassa retrospective, 1974-1997: effects of flow regulation on the lower Zambezi River, Verh. Int. Ver. Theor. Angew., 20, 2149–2157, 2000.
del Giorgio, P. A. and Pace, M. L.: Relative independence of dissolved organic carbon transport and processing in a large temperate river: the Hudson River as both pipe and reactor, Limnol. Oceanogr., 53, 185–197, 2008.
Dosskey, M. G. and Bertsch, P. M.: Forest sources and pathways of organic matter transport to a blackwater stream: a hydrologic approach, Biogeochemistry, 24, 1–19, 1994.
Duan, S., Bianchi, T., and Sampere, T. P.: Temporal variability in the composition and abundance of terrestrially-derived dissolved organic matter in the lower Mississippi and Pearl Rivers, Mar. Chem., 103, 172–184, https://doi.org/10.1016/j.marchem.2006.07.003, 2007.
Fasching, C., Behounek, B., Singer, G. A., and Battin, T. J.: Microbial degradation of terrigenous dissolved organic matter and potential consequences for carbon cycling in brown-water streams, Sci. Rep., 4, 4981, https://doi.org/10.1038/srep04981, 2014.
Fiebig, D. M., Lock, M. A., and Neal, C.: Soil water in the riparian zone as a source of carbon for a headwater stream, J. Hydrol., 116, 217–237, 1990.
Goodman, K. J., Baker, M. A., and Wurtsbaugh, W. A.: Lakes as buffers of stream dissolved organic matter (DOM) variability: temporal patterns of DOM characteristics in mountain stream-lake systems, J. Geosphys. Res., 116, G00N02, https://doi.org/10.1029/2011JG001709, 2011.
Hanley, K., Wollheim, W. M., Salisbury, J., Huntington, T., and Aiken, G.: Controls on dissolved organic carbon quantity and chemical character in temperate rivers of North America, Global Biogeochem. Cy., 27, 492–504, https://doi.org/10.1002/gbc.20044, 2013.
Hanson, P. C., Hamilton, D. P., Stanley, E. H., Preston, N., Langman, O. C., and Kara, E. L.: Fate of allochthonous dissolved organic carbon in lakes: a quantitative approach, PLoS ONE, 6, e21884, https://doi.org/10.1371/journal.pone.0021884, 2011.
Helms, J. R., Stubbins, A., Ritchie, J. D., Minor, E. C., Kieber, D. J., and Mopper, K.: Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter, Limnol. Oceanogr., 53, 955–969, 2008.
Hijmans, R. J., Cameron, S. E, Parra, J. L., Jones, P. G., and Jarvis, A.: Very high resolution interpolated climate surfaces for global land areas, Int. J. Climatol., 25, 1965–1978, available at: http://www.worldclim.org/ (last access: 2 October 2015), 2005.
Hinton, M. J., Schiff, S. L., and English, M. C.: Sources and flow- paths of dissolved organic carbon during storms in two forested watershed of the Precambrian Shield, Biogeochemistry, 41, 175–197, 1998.
Holmes, R. M., McClelland, J. W., Raymond, P. A., Frazer, B. B., Peterson, B. J., and Stieglitz, M.: Lability of DOC transported by Alaskan rivers to the arctic ocean, Geophys. Res. Lett., 35, L03402, https://doi.org/10.1029/2007gl032837, 2008.
Jaffé, R., McKnight, D., Maie, N., Cory, R., McDowell, W. H., and Campbell, J. L.: Spatial and temporal variations in DOM composition in ecosystems: The importance of long-term monitoring of optical properties, J. Geophys. Res.-Biogeo., 113, G04032, https://doi.org/10.1029/2008jg000683, 2008.
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.
Jørgensen, L., Stedmon, C. A., Kragh, T., Markager, S., Middelboe, M., and Søndergaard, M.: Global trends in the fluorescence characteristics and distribution of marine dissolved organic matter, Mar. Chem., 126, 139–148, https://doi.org/10.1016/j.marchem.2011.05.002, 2011.
Kellerman, A. M., Kothawala, D. N., Dittmar, T., and Tranvik, L. J.: Persistence of dissolved organic matter in lakes related to its molecular characteristics, Nat. Geosci., 8, 454–457, https://doi.org/10.1038/ngeo2440, 2015.
Köhler, S. J., Kothawala, D., Futter, M. N., Liungman, O., and Tranvik, L.: In-lake processes offset increased terrestrial inputs of dissolved organic carbon and color in lakes, PLoS ONE, 8, e70598, https://doi.org/10.1371/journal.pone.0070598, 2013.
Kohn, J. M.: Carbon isotope compositions of terrestrial C3 plants as indicators of (paleo)ecology and (paleo)climate, P. Natl. Acad. Sci. USA, 107, 19691–19695, 2010.
Kothawala, D. N., Stedmon, C. A., Müller, R. A., Weyhenmeyer, G. A., Köhler, S. J., and Tranvik, L. J.: Controls of dissolved organic matter quality: Evidence from a large-scale boreal lake survey, Glob. Change Biol., 20, 1101–1114, https://doi.org/10.1111/gcb.12488, 2014.
Kothawala, D. N., Ji, X., Laudon, H., Ågren, A., Futter, M. N., Köhler, S. J., and Tranvik, L. J.: The relative influence of land cover, hydrology, and in-stream processing on the composition of dissolved organic matter in boreal streams, J. Geosphys. Res-Biogeo., 120, 1491–1505, https://doi.org/10.1002/2015JG002946, 2015.
Kunz, M. J., Wuest, 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.
Lambert, T., Darchambeau, F., Bouillon, S., Alhou, B., Mbega, J.-D., Teodoru, C. R., Nyoni, F. C., and Borges, A. V.: Landscape control on the spatial and temporal variability of chromophoric dissolved organic matter and dissolved organic carbon in large African rivers, Ecosystems, 18, 1224–1239, https://doi.org/10.?1007/?s10021-015-9894-5, 2015.
Lapierre, J. F. and Frenette, J. J.: Effects of macrophytes and terrestrial inputs on fluorescent dissolved organic matter in a large river system, Aquat. Sci., 71, 15–24, https://doi.org/10.1007/s00027-009-9133-2, 2009.
Lehner, B. and Döll, P.: Development and validation of a global database of lakes, reservoirs and wetlands, J. Hydrol., 296, 1–22, https://doi.org/10.1016/j.jhydrol.2004.03.028, available at: http://www.worldwildlife.org/pages/global-lakes-and-wetlands-database (last access: 15 June 2015), 2004.
Lehner, B., Verdin, K., and Jarvis, A.: New global hydrography derived from space borne elevation data, Eos, 89, 93–94, available at: http://hydrosheds.cr.usgs.gov/index.php (last access: 15 June 2012), 2008.
Lottig, N. R., Buffam, I., and Stanley, E. H.: Comparisons of wetland and drainage lake influences on stream dissolved organic concentrations and yields in a north temperate lake-rich region, Aquat. Sci., 75, 619–630, https://doi.org/10.1007/s00027-013-0305-8, 2013.
Magadza, C.: Environmental state of Lake Kariba and Zambezi River Valley: Lessons learned and not learned, Lakes & Reservoirs: Research & Management, 15, 167–192, https://doi.org/10.1111/j.1440-1770.2010.00438.x, 2010.
Mann, P. J., Davydova, A., Zimov, N., Spencer, R. G. M., Davydov, S., Bulygina, E., Zimov, S., and Holmes, R. M.: Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin, J. Geosphys. Res., 117, G01028, https://doi.org/10.1029/2011JG001798, 2012.
Marín-Spiotta, E., Gruley, K. E., Crawford, J., Atkinson, E. E., Miesel, J. R., Greene, S., Cardona-Correa, C., and Spencer, R. G. M.: Paradigm shifts in soil organic matter research affect interpretations of aquatic carbon cycling: transcending disciplinary and ecosystem boundaries, Biogeochemistry, 117, 279–297, https://doi.org/10.1007/s10533-013-9949-7, 2014.
Marwick, T., Borges, A. V., Van Acker, K., Darchambeau, F., and Bouillon, S.: Disproportionate Contribution of Riparian Inputs to Organic Carbon Pools in Freshwater Systems, Ecosystems, 17, 974–989, 2014.
Massicotte, P. and Frenette, J.-J.: Spatial connectivity in a large river system: resolving the sources and fate of dissolved organic matter, Ecol. Appl., 21, 2600–2617, 2011.
Mayaux, P., Bartholomé, E., Fritz, S., and Belward, A.: A new land-cover map of Africa for the year 2000, J. Biogeogr., 31, 861–877, 2004.
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.
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.
Meybeck, M.: Riverine transport of atmospheric carbon: source, global typology and budget, Water Air Soil Pollut., 70, 443–463, 1993.
Mladenov, N, McKnight, D. M., Macko, S. A., Norris, M., Cory, R. M., and Ramberg, L.: Chemical characterization of DOM in channels of a seasonal wetland, Aquat. Sci., 69, 456–471, https://doi.org/10.1007/s00027-007-0905-2, 2007.
Moran, M. A., Sheldon, W. M., and Zepp, R. G.: Carbon loss and optical property changes during long-term photochemical and biological degradation of estuarine dissolved organic matter, Limnol. Oceanogr., 45, 1254–1264, 2000.
Neff, J. C., Finlay, J. C., Zimov, S. A., Davydov, S. P., Carrasco, J. J., Schuur, E. A. G., and Davydova, A. I.: Seasonal changes in the age and structure of dissolved organic carbon in Siberian rivers and streams, Geophys. Res. Lett., 33, L23401, https://doi.org/10.1029/2006GL028222, 2006.
Ohno, T.: Fluorescence inner-filtering correction for determining the humification index of dissolved organic matter, Environ. Sci. Technol., 36, 742–746, https://doi.org/10.1021/Es0155276, 2002.
Parks, S. J. and Baker, L. A.: Sources and transport of organic carbon in an Arizona river-reservoir system, Water Resour., 31, 1751–1759, 1997.
Raymond, P. A., Saiers, J. E., and Sobczak W. V.: Hydrological and biogeochemical controls on watershed dissolved organic matter transport: pulse-shunt concept, Ecology, 97, 5–16, https://doi.org/10.1890/14-1684.1, 2016.
Schlesinger, W. H. and Melack, J. M.: Transport of organic carbon in the world's rivers, Tellus, 33, 172–187, 1981.
Spencer, R. G. M., Stubbins, A., Hernes, P. J., Baker, A., Mopper, K., Aufdenkampe, A. K., Dyda, R. Y., Mwamba, V. L., Mangangu, A. M., Wabakanghanzi, J. N., and Six, J.: Photochemical degradation of dissolved organic matter and dissolved lignin phenols from the Congo River, J. Geophys. Res.-Biogeo., 114, G03010, https://doi.org/10.1029/2009jg000968, 2009.
Stackpoole, S. M., Stets, E. G., and Striegl, R. G.: The impact of climate and reservoirs on longitudinal riverine carbon fluxes from two major watersheds in the Central and Intermontane West, J. Geophys. Res-Biogeo., 119, 848–863, https://doi.org/10.1002/2013JG002496, 2014.
Stedmon, C. A. and Markager, S.: Resolving the variability in DOM fluorescence in a temperate estuary and its catchment unsing PARAFAC, 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.
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.
Striegl, R. S., Aiken, G. R., Domblaser, M. M., Raymond, P. A., and Wickland, K. P.: A decrease in discharge-normalized DOC export by the Yukon River during summer through autumn, Geophys. Res. Lett., 32, L21413, https://doi.org/10.1029/2005GL024413, 2005.
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.
Teodoru, C. R., Nyoni, F. C., Borges, A. V., Darchambeau, F., Nyambe, I., and Bouillon, S.: Dynamics of greenhouse gases (CO2, CH4, N2O) along the Zambezi River and major tributaries, and their importance in the riverine carbon budget, Biogeosciences, 12, 2431–2453, https://doi.org/10.5194/bg-12-2431-2015, 2015.
von Wachenfekdt, E. and Tranvik, L. J.: Sedimentation in Boreal lakes – the role of flocculation of allochthonous dissolved organic matter in the water column, Ecosystems, 11, 803–814, https://doi.org/10.1007/s10021-008-9162-z, 2008.
Walker, S. A., Amon, R. M., and Stedmon, C. A.: Variations in high-latitude riverine fluorescent dissolved organic matter: A comparison of large Arctic rivers, J. Geosphys. Res-Biogeo., 118, 1689–1702, https://doi.org/10.1002/2013JG002320, 2013.
Ward, N. D., Keil, R. G., Medeiros, P. M., Brito, D. C., Cunha, A. C., Dittmar, T., Yager, P. L., Krusche, A. V., and Richey, J. E.: Degradation of terrestrially derived macromolecules in the Amazon River, Nat. Geosci., 6, 530–533, https://doi.org/10.1038/ngeo1817, 2013.
Ward, N. D., Krusche, A. V., Sawakuchi, H. O., Brito, D. C., Cunha, A. C., Moura, J. M. S., da Silva, R., Keil, R. G., and Richey, J. E.: The compositional evolution of dissolved and particulate organic matter along the lower Amazon River-Óbidos to the ocean, Mar. Chem., 177, 244–256, doi.org/10.1016/j.marchem.2015.06.013, 2015.
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.
Wellington, J. H.: Southern Africa – a Geographic Study, vol. 1, Physical Geography, Cambridge University Press, Cambridge, 528 pp., 1955.
Weyhenmeyer, G. A., Fröberg, M., Karltun, E., Khalili, M., Kothawala, D., Temnerud, J., and Tranvik, L. J.: Selective decay of terrestrial organic carbon during transport from land to sea, Glob. Change Biol., 18, 349–355, https://doi.org/10.1111/j.1365-2486.2011.02544.x, 2012.
Winterdahl, M., Erlandsson, M., Futter, M. N., Weyhenmeyer, G. A., and Bishop, K.: Intra-annual variability of organic carbon concentrations in running waters: Drivers along a climatic gradient, Global Biogeochem. Cy., 28, 451–464, https://doi.org/10.1002/2013GB004770, 2014.
Yamashita, Y., Jaffé, R., Maie, N., and Tanoue, E.: Assessing the dynamics of dissolved organic matter (DOM) in coastal environments by excitation emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC), Limnol. Oceanogr., 53, 1900–1908, 2008.
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, 2010.
Zepp, R. G., Sheldon, W. M., and Moran, M. A.: Dissolved organic fluorophores in southeastern US coastal waters: correction method for eliminating Rayleigh and Raman scattering peaks in excitation–emission matrices, Mar. Chem., 89, 15–36, https://doi.org/10.1016/j.marchem.2004.02.006, 2004.
Zurbrügg, R., Suter, S., Lehmann, M. F., Wehrli, B., and Senn, D. B.: Organic carbon and nitrogen export from a tropical dam-impacted floodplain system, Biogeosciences, 10, 23–38, https://doi.org/10.5194/bg-10-23-2013, 2013.
Short summary
This manuscript presents a detailed analysis of transport and transformation of dissolved organic matter along the Zambezi River and its largest tributary. A particular focus is put on the effects of floodplains/wetlands and reservoirs as well as low-flow vs. high-flow conditions on the longitudinal patterns in DOM concentration and composition. It is the first study to present such a detailed analysis for a whole, large river system, and in particular for a tropical river other than the Amazon.
This manuscript presents a detailed analysis of transport and transformation of dissolved...
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