Articles | Volume 15, issue 10
Research article 18 May 2018
Research article | 18 May 2018
Groundwater data improve modelling of headwater stream CO2 outgassing with a stable DIC isotope approach
Anne Marx et al.
No articles found.
Inga Köhler, Raul E. Martinez, David Piatka, Achim J. Herrmann, Arianna Gallo, Michelle M. Gehringer, and Johannes A. C. Barth
Biogeosciences, 18, 4535–4548,Short summary
We investigated how high Fe(II) levels influence the O2 budget of a circum-neutral Fe(II)-rich spring and if a combined study of dissolved O (DO) and its isotopic composition can help assess this effect. We showed that dissolved Fe(II) can exert strong effects on the δ18ODO even though a constant supply of atmospheric O2 occurs. In the presence of photosynthesis, direct effects of Fe oxidation become masked. Critical Fe(II) concentrations indirectly control the DO by enhancing photosynthesis.
Tobias R. Juhlke, Jürgen Sültenfuß, Katja Trachte, Frédéric Huneau, Emilie Garel, Sébastien Santoni, Johannes A. C. Barth, and Robert van Geldern
Atmos. Chem. Phys., 20, 3555–3568,Short summary
Tritium can serve as a useful tracer in the hydrological cycle; however, aspects of the distribution and exchange of tritium in the atmosphere are not completely understood. In particular, the movement of tritium from its natural origin in the upper atmosphere to its deposition onto the land surface by precipitation has to be quantified further. Therefore, this study collected precipitation event samples and used atmospheric models in order to improve knowledge regarding tritium dynamics.
Related subject area
Biogeochemistry: Modelling, AquaticModeling the marine chromium cycle: new constraints on global-scale processesNew insights into large-scale trends of apparent organic matter reactivity in marine sediments and patterns of benthic carbon transformationEvaluation of ocean dimethylsulfide concentration and emission in CMIP6 modelsZooplankton mortality effects on the plankton community of the northern Humboldt Current System: sensitivity of a regional biogeochemical modelMulti-compartment kinetic–allometric (MCKA) model of radionuclide bioaccumulation in marine fishImpact of bottom trawling on sediment biogeochemistry: a modelling approachCyanobacteria blooms in the Baltic Sea: a review of models and factsArctic Ocean acidification over the 21st century co-driven by anthropogenic carbon increases and freshening in the CMIP6 model ensembleModeling silicate–nitrate–ammonium co-limitation of algal growth and the importance of bacterial remineralization based on an experimental Arctic coastal spring bloom culture studyA modeling study of temporal and spatial pCO2 variability on the biologically active and temperature-dominated Scotian ShelfRole of jellyfish in the plankton ecosystem revealed using a global ocean biogeochemical modelExtreme event waves in marine ecosystems: an application to Mediterranean Sea surface chlorophyllUse of optical absorption indices to assess seasonal variability of dissolved organic matter in Amazon floodplain lakesThe role of sediment-induced light attenuation on primary production during Hurricane Gustav (2008)Quantifying spatiotemporal variability in zooplankton dynamics in the Gulf of Mexico with a physical–biogeochemical modelOne size fits all? Calibrating an ocean biogeochemistry model for different circulationsAssessing the temporal scale of deep-sea mining impacts on sediment biogeochemistrySeasonal patterns of surface inorganic carbon system variables in the Gulf of Mexico inferred from a regional high-resolution ocean biogeochemical modelOxygen dynamics and evaluation of the single-station diel oxygen model across contrasting geologiesOceanic CO2 outgassing and biological production hotspots induced by pre-industrial river loads of nutrients and carbon in a global modeling approachGlobal trends in marine nitrate N isotopes from observations and a neural network-based climatologyMerging bio-optical data from Biogeochemical-Argo floats and models in marine biogeochemistryModel constraints on the anthropogenic carbon budget of the Arctic OceanModeling oceanic nitrate and nitrite concentrations and isotopes using a 3-D inverse N cycle modelBiogeochemical response of the Mediterranean Sea to the transient SRES-A2 climate change scenarioModelling the biogeochemical effects of heterotrophic and autotrophic N2 fixation in the Gulf of Aqaba (Israel), Red SeaA perturbed biogeochemistry model ensemble evaluated against in situ and satellite observationsDiazotrophy as the main driver of the oligotrophy gradient in the western tropical South Pacific Ocean: results from a one-dimensional biogeochemical–physical coupled modelCauses of simulated long-term changes in phytoplankton biomass in the Baltic proper: a wavelet analysisModelling N2 fixation related to Trichodesmium sp.: driving processes and impacts on primary production in the tropical Pacific OceanLong-term response of oceanic carbon uptake to global warming via physical and biological pumpsSeasonal patterns in phytoplankton biomass across the northern and deep Gulf of Mexico: a numerical model studySea-surface dimethylsulfide (DMS) concentration from satellite data at global and regional scalesA new look at the multi-G model for organic carbon degradation in surface marine sediments for coupled benthic–pelagic simulations of the global oceanThe influence of the ocean circulation state on ocean carbon storage and CO2 drawdown potential in an Earth system modelModelling potential production of macroalgae farms in UK and Dutch coastal watersAssimilating bio-optical glider data during a phytoplankton bloom in the southern Ross SeaPrimary production sensitivity to phytoplankton light attenuation parameter increases with transient forcingOn the long-range offshore transport of organic carbon from the Canary Upwelling System to the open North AtlanticImproving the inverse modeling of a trace isotope: how precisely can radium-228 fluxes toward the ocean and submarine groundwater discharge be estimated?Implications of sea-ice biogeochemistry for oceanic production and emissions of dimethyl sulfide in the ArcticA numerical analysis of biogeochemical controls with physical modulation on hypoxia during summer in the Pearl River estuaryPotential sources of variability in mesocosm experiments on the response of phytoplankton to ocean acidificationA data–model synthesis to explain variability in calcification observed during a CO2 perturbation mesocosm experimentReviews and syntheses: parameter identification in marine planktonic ecosystem modellingManganese in the west Atlantic Ocean in the context of the first global ocean circulation model of manganeseGrowth of the coccolithophore Emiliania huxleyi in light- and nutrient-limited batch reactors: relevance for the BIOSOPE deep ecological niche of coccolithophoresBiogeochemical fluxes and fate of diazotroph-derived nitrogen in the food web after a phosphate enrichment: modeling of the VAHINE mesocosms experimentMarine regime shifts in ocean biogeochemical models: a case study in the Gulf of AlaskaModeling pCO2 variability in the Gulf of Mexico
Frerk Pöppelmeier, David J. Janssen, Samuel L. Jaccard, and Thomas F. Stocker
Biogeosciences, 18, 5447–5463,Short summary
Chromium (Cr) is a redox-sensitive element that holds promise as a tracer of ocean oxygenation and biological activity. We here implemented the oxidation states Cr(III) and Cr(VI) in the Bern3D model to investigate the processes that shape the global Cr distribution. We find a Cr ocean residence time of 5–8 kyr and that the benthic source dominates the tracer budget. Further, regional model–data mismatches suggest strong Cr removal in oxygen minimum zones and a spatially variable benthic source.
Felipe S. Freitas, Philip A. Pika, Sabine Kasten, Bo B. Jørgensen, Jens Rassmann, Christophe Rabouille, Shaun Thomas, Henrik Sass, Richard D. Pancost, and Sandra Arndt
Biogeosciences, 18, 4651–4679,Short summary
It remains challenging to fully understand what controls carbon burial in marine sediments globally. Thus, we use a model–data approach to identify patterns of organic matter reactivity at the seafloor across distinct environmental conditions. Our findings support the notion that organic matter reactivity is a dynamic ecosystem property and strongly influences biogeochemical cycling and exchange. Our results are essential to improve predictions of future changes in carbon cycling and climate.
Josué Bock, Martine Michou, Pierre Nabat, Manabu Abe, Jane P. Mulcahy, Dirk J. L. Olivié, Jörg Schwinger, Parvadha Suntharalingam, Jerry Tjiputra, Marco van Hulten, Michio Watanabe, Andrew Yool, and Roland Séférian
Biogeosciences, 18, 3823–3860,Short summary
In this study we analyse surface ocean dimethylsulfide (DMS) concentration and flux to the atmosphere from four CMIP6 Earth system models over the historical and ssp585 simulations. Our analysis of contemporary (1980–2009) climatologies shows that models better reproduce observations in mid to high latitudes. The models disagree on the sign of the trend of the global DMS flux from 1980 onwards. The models agree on a positive trend of DMS over polar latitudes following sea-ice retreat dynamics.
Mariana Hill Cruz, Iris Kriest, Yonss Saranga José, Rainer Kiko, Helena Hauss, and Andreas Oschlies
Biogeosciences, 18, 2891–2916,Short summary
In this study we use a regional biogeochemical model of the eastern tropical South Pacific Ocean to implicitly simulate the effect that fluctuations in populations of small pelagic fish, such as anchovy and sardine, may have on the biogeochemistry of the northern Humboldt Current System. To do so, we vary the zooplankton mortality in the model, under the assumption that these fishes eat zooplankton. We also evaluate the model for the first time against mesozooplankton observations.
Roman Bezhenar, Kyeong Ok Kim, Vladimir Maderich, Govert de With, and Kyung Tae Jung
Biogeosciences, 18, 2591–2607,Short summary
A new approach to predicting the accumulation of radionuclides in fish was developed by taking into account heterogeneity of distribution of contamination in the organism and dependence of metabolic process rates on the fish mass. Predicted concentrations of radionuclides in fish agreed well with the laboratory and field measurements. The model with the defined generic parameters could be used in marine environments without local calibration, which is important for emergency decision support.
Emil De Borger, Justin Tiano, Ulrike Braeckman, Adriaan D. Rijnsdorp, and Karline Soetaert
Biogeosciences, 18, 2539–2557,Short summary
Bottom trawling alters benthic mineralization: the recycling of organic material (OM) to free nutrients. To better understand how this occurs, trawling events were added to a model of seafloor OM recycling. Results show that bottom trawling reduces OM and free nutrients in sediments through direct removal thereof and of fauna which transport OM to deeper sediment layers protected from fishing. Our results support temporospatial trawl restrictions to allow key sediment functions to recover.
Britta Munkes, Ulrike Löptien, and Heiner Dietze
Biogeosciences, 18, 2347–2378,Short summary
Cyanobacteria blooms can strongly aggravate eutrophication problems of water bodies. Their controls are, however, not comprehensively understood, which impedes effective management and protection plans. Here we review the current understanding of cyanobacteria blooms. Juxtaposition of respective field and laboratory studies with state-of-the-art mathematical models reveals substantial uncertainty associated with nutrient demands, grazing, and death of cyanobacteria.
Jens Terhaar, Olivier Torres, Timothée Bourgeois, and Lester Kwiatkowski
Biogeosciences, 18, 2221–2240,Short summary
The uptake of carbon, emitted as a result of human activities, results in ocean acidification. We analyse 21st-century projections of acidification in the Arctic Ocean, a region of particular vulnerability, using the latest generation of Earth system models. In this new generation of models there is a large decrease in the uncertainty associated with projections of Arctic Ocean acidification, with freshening playing a greater role in driving acidification than previously simulated.
Tobias R. Vonnahme, Martial Leroy, Silke Thoms, Dick van Oevelen, H. Rodger Harvey, Svein Kristiansen, Rolf Gradinger, Ulrike Dietrich, and Christoph Völker
Biogeosciences, 18, 1719–1747,Short summary
Diatoms are crucial for Arctic coastal spring blooms, and their growth is controlled by nutrients and light. At the end of the bloom, inorganic nitrogen or silicon can be limiting, but nitrogen can be regenerated by bacteria, extending the algal growth phase. Modeling these multi-nutrient dynamics and the role of bacteria is challenging yet crucial for accurate modeling. We recreated spring bloom dynamics in a cultivation experiment and developed a representative dynamic model.
Krysten Rutherford, Katja Fennel, Dariia Atamanchuk, Douglas Wallace, and Helmuth Thomas
Revised manuscript accepted for BGShort summary
Using a regional model of the northwestern North Atlantic shelves in combination with a surface water time series and repeat transect observations, we investigate surface CO2 variability on the Scotian Shelf. The study highlights a strong seasonal cycle in shelf-wide pCO2 and spatial variability throughout the summer months driven by physical events. The simulated net flux of CO2 on the Scotian Shelf is out of the ocean, deviating from the global air-sea CO2 flux trend in continental shelves.
Rebecca M. Wright, Corinne Le Quéré, Erik Buitenhuis, Sophie Pitois, and Mark J. Gibbons
Biogeosciences, 18, 1291–1320,Short summary
Jellyfish have been included in a global ocean biogeochemical model for the first time. The global mean jellyfish biomass in the model is within the observational range. Jellyfish are found to play an important role in the plankton ecosystem, influencing community structure, spatiotemporal dynamics and biomass. The model raises questions about the sensitivity of the zooplankton community to jellyfish mortality and the interactions between macrozooplankton and jellyfish.
Valeria Di Biagio, Gianpiero Cossarini, Stefano Salon, and Cosimo Solidoro
Biogeosciences, 17, 5967–5988,Short summary
Events that influence the functioning of the Earth’s ecosystems are of interest in relation to a changing climate. We propose a method to identify and characterise
wavesof extreme events affecting marine ecosystems for multi-week periods over wide areas. Our method can be applied to suitable ecosystem variables and has been used to describe different kinds of extreme event waves of phytoplankton chlorophyll in the Mediterranean Sea, by analysing the output from a high-resolution model.
Maria Paula da Silva, Lino A. Sander de Carvalho, Evlyn Novo, Daniel S. F. Jorge, and Claudio C. F. Barbosa
Biogeosciences, 17, 5355–5364,Short summary
In this study, we analyze the seasonal changes in the dissolved organic matter (DOM) quality (based on its optical properties) in four Amazon floodplain lakes. DOM plays a fundamental role in surface water chemistry, controlling metal bioavailability and mobility, and nutrient cycling. The model proposed in our paper highlights the potential to study DOM quality at a wider spatial scale, which may help to better understand the persistence and fate of DOM in the ecosystem.
Zhengchen Zang, Z. George Xue, Kehui Xu, Samuel J. Bentley, Qin Chen, Eurico J. D'Sa, Le Zhang, and Yanda Ou
Biogeosciences, 17, 5043–5055,
Taylor A. Shropshire, Steven L. Morey, Eric P. Chassignet, Alexandra Bozec, Victoria J. Coles, Michael R. Landry, Rasmus Swalethorp, Glenn Zapfe, and Michael R. Stukel
Biogeosciences, 17, 3385–3407,Short summary
Zooplankton are the smallest animals in the ocean and important food for fish. Despite their importance, zooplankton have been relatively undersampled. To better understand the zooplankton community in the Gulf of Mexico (GoM), we developed a model to simulate their dynamics. We found that heterotrophic protists are important for supporting mesozooplankton, which are the primary prey of larval fish. The model developed in this study has the potential to improve fisheries management in the GoM.
Iris Kriest, Paul Kähler, Wolfgang Koeve, Karin Kvale, Volkmar Sauerland, and Andreas Oschlies
Biogeosciences, 17, 3057–3082,Short summary
Constants of global biogeochemical ocean models are often tuned
by handto match observations of nutrients or oxygen. We investigate the effect of this tuning by optimising six constants of a global biogeochemical model, simulated in five different offline circulations. Optimal values for three constants adjust to distinct features of the circulation applied and can afterwards be swapped among the circulations, without losing too much of the model's fit to observed quantities.
Laura Haffert, Matthias Haeckel, Henko de Stigter, and Felix Janssen
Biogeosciences, 17, 2767–2789,Short summary
Deep-sea mining for polymetallic nodules is expected to have severe environmental impacts. Through prognostic modelling, this study aims to provide a holistic assessment of the biogeochemical recovery after a disturbance event. It was found that the recovery strongly depends on the impact type; e.g. complete removal of the surface sediment reduces seafloor nutrient fluxes over centuries.
Fabian A. Gomez, Rik Wanninkhof, Leticia Barbero, Sang-Ki Lee, and Frank J. Hernandez Jr.
Biogeosciences, 17, 1685–1700,Short summary
We use a numerical model to infer annual changes of surface carbon chemistry in the Gulf of Mexico (GoM). The main seasonality drivers of partial pressure of carbon dioxide and aragonite saturation state from the model are temperature and river runoff. The GoM basin is a carbon sink in winter–spring and carbon source in summer–fall, but uptake prevails near the Mississippi Delta year-round due to high biological production. Our model results show good correspondence with observational studies.
Simon J. Parker
Biogeosciences, 17, 305–315,Short summary
Dissolved oxygen (DO) models typically assume constant ecosystem respiration over the course of a single day. Using a data-driven approach, this research examines this assumption in four streams across two (hydro-)geological types (Chalk and Greensand). Despite hydrogeological equivalence in terms of baseflow index for each hydrogeological pairing, model suitability differed within, rather than across, geology types. This corresponded with associated differences in timings of DO minima.
Fabrice Lacroix, Tatiana Ilyina, and Jens Hartmann
Biogeosciences, 17, 55–88,Short summary
Contributions of rivers to the oceanic cycling of carbon have been poorly represented in global models until now. Here, we assess the long–term implications of preindustrial riverine loads in the ocean in a novel framework which estimates the loads through a hierarchy of weathering and land–ocean export models. We investigate their impacts for the oceanic biological production and air–sea carbon flux. Finally, we assess the potential incorporation of the framework in an Earth system model.
Patrick A. Rafter, Aaron Bagnell, Dario Marconi, and Timothy DeVries
Biogeosciences, 16, 2617–2633,Short summary
The N isotopic composition of nitrate (
nitrate δ15N) is a useful tracer of ocean N cycling and many other ocean processes. Here, we use a global compilation of marine nitrate δ15N as an input, training, and validating dataset for an artificial neural network (a.k.a.,
machine learning) and examine basin-scale trends in marine nitrate δ15N from the surface to the seafloor.
Elena Terzić, Paolo Lazzari, Emanuele Organelli, Cosimo Solidoro, Stefano Salon, Fabrizio D'Ortenzio, and Pascal Conan
Biogeosciences, 16, 2527–2542,Short summary
Measuring ecosystem properties in the ocean is a hard business. Recent availability of data from Biogeochemical-Argo floats can help make this task easier. Numerical models can integrate these new data in a coherent picture and can be used to investigate the functioning of ecosystem processes. Our new approach merges experimental information and model capabilities to quantitatively demonstrate the importance of light and water vertical mixing for algae dynamics in the Mediterranean Sea.
Jens Terhaar, James C. Orr, Marion Gehlen, Christian Ethé, and Laurent Bopp
Biogeosciences, 16, 2343–2367,Short summary
A budget of anthropogenic carbon in the Arctic Ocean, the main driver of open-ocean acidification, was constructed for the first time using a high-resolution ocean model. The budget reveals that anthropogenic carbon enters the Arctic Ocean mainly by lateral transport; the air–sea flux plays a minor role. Coarser-resolution versions of the same model, typical of earth system models, store less anthropogenic carbon in the Arctic Ocean and thus underestimate ocean acidification in the Arctic Ocean.
Taylor S. Martin, François Primeau, and Karen L. Casciotti
Biogeosciences, 16, 347–367,Short summary
Nitrite is a key intermediate in many nitrogen (N) cycling processes in the ocean, particularly in areas with low oxygen that are hotspots for N loss. We have created a 3-D global N cycle model with nitrite as a tracer. Stable isotopes of N are also included in the model and we are able to model the isotope fractionation associated with each N cycling process. Our model accurately represents N concentrations and isotope distributions in the ocean.
Camille Richon, Jean-Claude Dutay, Laurent Bopp, Briac Le Vu, James C. Orr, Samuel Somot, and François Dulac
Biogeosciences, 16, 135–165,Short summary
We evaluate the effects of climate change and biogeochemical forcing evolution on the nutrient and plankton cycles of the Mediterranean Sea for the first time. We use a high-resolution coupled physical and biogeochemical model and perform 120-year transient simulations. The results indicate that changes in external nutrient fluxes and climate change may have synergistic or antagonistic effects on nutrient concentrations, depending on the region and the scenario.
Angela M. Kuhn, Katja Fennel, and Ilana Berman-Frank
Biogeosciences, 15, 7379–7401,Short summary
Recent studies demonstrate that marine N2 fixation can be carried out without light. However, direct measurements of N2 fixation in dark environments are relatively scarce. This study uses a model that represents biogeochemical cycles at a deep-ocean location in the Gulf of Aqaba (Red Sea). Different model versions are used to test assumptions about N2 fixers. Relaxing light limitation for marine N2 fixers improved the similarity between model results and observations of deep nitrate and oxygen.
Prima Anugerahanti, Shovonlal Roy, and Keith Haines
Biogeosciences, 15, 6685–6711,Short summary
Minor changes in the biogeochemical model equations lead to major dynamical changes. We assessed this structural sensitivity for the MEDUSA biogeochemical model on chlorophyll and nitrogen concentrations at five oceanographic stations over 10 years, using 1-D ensembles generated by combining different process equations. The ensemble performed better than the default model in most of the stations, suggesting that our approach is useful for generating a probabilistic biogeochemical ensemble model.
Audrey Gimenez, Melika Baklouti, Thibaut Wagener, and Thierry Moutin
Biogeosciences, 15, 6573–6589,Short summary
During the OUTPACE cruise conducted in the oligotrophic to ultra-oligotrophic region of the western tropical South Pacific, two contrasted regions were sampled in terms of N2 fixation rates, primary production rates and nutrient availability. The aim of this work was to investigate the role of N2 fixation in the differences observed between the two contrasted areas by comparing two simulations only differing by the presence or not of N2 fixers using a 1-D biogeochemical–physical coupled model.
Jenny Hieronymus, Kari Eilola, Magnus Hieronymus, H. E. Markus Meier, Sofia Saraiva, and Bengt Karlson
Biogeosciences, 15, 5113–5129,Short summary
This paper investigates how phytoplankton concentrations in the Baltic Sea co-vary with nutrient concentrations and other key variables on inter-annual timescales in a model integration over the years 1850–2008. The study area is not only affected by climate change; it has also been subjected to greatly increased nutrient loads due to extensive use of agricultural fertilizers. The results indicate the largest inter-annual coherence of phytoplankton with the limiting nutrient.
Cyril Dutheil, Olivier Aumont, Thomas Gorguès, Anne Lorrain, Sophie Bonnet, Martine Rodier, Cécile Dupouy, Takuhei Shiozaki, and Christophe Menkes
Biogeosciences, 15, 4333–4352,Short summary
N2 fixation is recognized as one of the major sources of nitrogen in the ocean. Thus, N2 fixation sustains a significant part of the primary production (PP) by supplying the most common limiting nutrient for phytoplankton growth. From numerical simulations, the local maximums of Trichodesmium biomass in the Pacific are found around islands, explained by the iron fluxes from island sediments. We assessed that 15 % of the PP may be due to Trichodesmium in the low-nutrient, low-chlorophyll areas.
Akitomo Yamamoto, Ayako Abe-Ouchi, and Yasuhiro Yamanaka
Biogeosciences, 15, 4163–4180,Short summary
Millennial-scale changes in oceanic CO2 uptake due to global warming are simulated by a GCM and offline biogeochemical model. Sensitivity studies show that decreases in oceanic CO2 uptake are mainly caused by a weaker biological pump and seawater warming. Enhanced CO2 uptake due to weaker equatorial upwelling cancels out reduced CO2 uptake due to weaker AMOC and AABW formation. Thus, circulation change plays only a small direct role in reduction of CO2 uptake due to global warming.
Fabian A. Gomez, Sang-Ki Lee, Yanyun Liu, Frank J. Hernandez Jr., Frank E. Muller-Karger, and John T. Lamkin
Biogeosciences, 15, 3561–3576,Short summary
Seasonal patterns in nanophytoplankton and diatom biomass in the Gulf of Mexico were examined with an ocean–biogeochemical model. We found silica limitation of model diatom growth in the deep GoM and Mississippi delta. Zooplankton grazing and both transport and vertical mixing of biomass substantially influence the model phytoplankton biomass seasonality. We stress the need for integrated analyses of biologically and physically driven biomass fluxes to describe phytoplankton seasonal changes.
Martí Galí, Maurice Levasseur, Emmanuel Devred, Rafel Simó, and Marcel Babin
Biogeosciences, 15, 3497–3519,Short summary
We developed a new algorithm to estimate the sea-surface concentration of dimethylsulfide (DMS) using satellite data. DMS is a gas produced by marine plankton that, once emitted to the atmosphere, plays a key climatic role by seeding cloud formation. We used the algorithm to produce global DMS maps and also regional DMS time series. The latter suggest that DMS can vary largely from one year to another, which should be taken into account in atmospheric studies.
Konstantin Stolpovsky, Andrew W. Dale, and Klaus Wallmann
Biogeosciences, 15, 3391–3407,Short summary
The paper describes a new way to parameterize G-type models in marine sediments using data about reactivity of organic carbon sinking to the seafloor.
Malin Ödalen, Jonas Nycander, Kevin I. C. Oliver, Laurent Brodeau, and Andy Ridgwell
Biogeosciences, 15, 1367–1393,Short summary
We conclude that different initial states for an ocean model result in different capacities for ocean carbon storage due to differences in the ocean circulation state and the origin of the carbon in the initial ocean carbon reservoir. This could explain why it is difficult to achieve comparable responses of the ocean carbon system in model inter-comparison studies in which the initial states vary between models. We show that this effect of the initial state is quantifiable.
Johan van der Molen, Piet Ruardij, Karen Mooney, Philip Kerrison, Nessa E. O'Connor, Emma Gorman, Klaas Timmermans, Serena Wright, Maeve Kelly, Adam D. Hughes, and Elisa Capuzzo
Biogeosciences, 15, 1123–1147,Short summary
Macroalgae farming may provide biofuel. Modelled macroalgae production is given for four sites in UK and Dutch waters. Macroalgae growth depended on nutrient concentrations and light levels. Macroalgae carbohydrate content, important for biofuel use, was lower for high nutrient concentrations. The hypothetical large-scale farm off the UK north Norfolk coast gave high, stable yields of macroalgae from year to year with substantial carbohydrate content.
Daniel E. Kaufman, Marjorie A. M. Friedrichs, John C. P. Hemmings, and Walker O. Smith Jr.
Biogeosciences, 15, 73–90,Short summary
Computer simulations of the highly variable phytoplankton in the Ross Sea demonstrated how incorporating data from different sources (satellite, ship, or glider) results in different system interpretations. For example, simulations assimilating satellite-based data produced lower carbon export estimates. Combining observations with models in this remote, harsh, and biologically variable environment should include consideration of the potential impacts of data frequency, duration, and coverage.
Karin F. Kvale and Katrin J. Meissner
Biogeosciences, 14, 4767–4780,Short summary
Climate models containing ocean biogeochemistry contain a lot of poorly constrained parameters, which makes model tuning difficult. For more than 20 years modellers have generally assumed phytoplankton light attenuation parameter value choice has an insignificant affect on model ocean primary production; thus, it is often overlooked for tuning. We show that an empirical range of light attenuation parameter values can affect primary production, with increasing sensitivity under climate change.
Elisa Lovecchio, Nicolas Gruber, Matthias Münnich, and Zouhair Lachkar
Biogeosciences, 14, 3337–3369,Short summary
We find that a big portion of the phytoplankton, zooplankton, and detrital organic matter produced near the northern African coast is laterally transported towards the open North Atlantic. This offshore flux sustains a relevant part of the biological activity in the open sea and reaches as far as the middle of the North Atlantic. Our results, obtained with a state-of-the-art model, highlight the fundamental role of the narrow but productive coastal ocean in sustaining global marine life.
Guillaume Le Gland, Laurent Mémery, Olivier Aumont, and Laure Resplandy
Biogeosciences, 14, 3171–3189,Short summary
In this study, we computed the fluxes of radium-228 from the continental shelf to the open ocean by fitting a numerical model to observations. After determining appropriate model parameters (cost function and number of source regions), we found a lower and more precise global flux than previous estimates: 8.01–8.49×1023 atoms yr−1. This result can be used to assess nutrient and trace element fluxes to the open ocean, but we cannot identify specific pathways like submarine groundwater discharge.
Hakase Hayashida, Nadja Steiner, Adam Monahan, Virginie Galindo, Martine Lizotte, and Maurice Levasseur
Biogeosciences, 14, 3129–3155,Short summary
In remote regions, cloud conditions may be strongly influenced by oceanic source of dimethylsulfide (DMS) produced by plankton and bacteria. In the Arctic, sea ice provides an additional source of these aerosols. The results of this study highlight the importance of taking into account both the sea-ice sulfur cycle and ecosystem in the flux estimates of oceanic DMS near the ice margins and identify key uncertainties in processes and rates that would be better constrained by new observations.
Bin Wang, Jiatang Hu, Shiyu Li, and Dehong Liu
Biogeosciences, 14, 2979–2999,Short summary
We proposed a novel method named the physical modulation method to quantify the contributions of boundary conditions, the source and sink processes occurring in local and adjacent waters to DO conditions. A mass balance analysis of DO based on the physical modulation method indicated that the DO conditions were mainly controlled by source and sink processes, among which the sediment oxygen demand and re-aeration were two main processes controlling the spatial extent and the duration of hypoxia.
Maria Moreno de Castro, Markus Schartau, and Kai Wirtz
Biogeosciences, 14, 1883–1901,Short summary
Observations from different mesocosms exposed to the same treatment level typically show variability that hinders the detection of potential treatments effects. To unearth relevant sources of variability, we developed and performed a data-based model analysis that simulates uncertainty propagation. With this method we investigate the divergence in the outcomes due to the amplification of differences in experimentally unresolved ecological factors within replicates of the same treatment level.
Shubham Krishna and Markus Schartau
Biogeosciences, 14, 1857–1882,Short summary
This study combines experimental data with results from numerical modelling. Data of an ocean acidification mesocosm experiment are used to constrain parameter values of a plankton model. Three different intensities of calcification are resolved with ensembles of optimised model results. Observed variability in data can be well explained by these ensemble model solutions. The simulated ocean acidification effect on calcification is small compared to the spread of the ensemble model solutions.
Markus Schartau, Philip Wallhead, John Hemmings, Ulrike Löptien, Iris Kriest, Shubham Krishna, Ben A. Ward, Thomas Slawig, and Andreas Oschlies
Biogeosciences, 14, 1647–1701,Short summary
Plankton models have become an integral part in marine ecosystem and biogeochemical research. These models differ in complexity and in their number of parameters. How values are assigned to parameters is essential. An overview of major methodologies of parameter estimation is provided. Aspects of parameter identification in the literature are diverse. Individual findings could be better synthesized if notation and expertise of the different scientific communities would be reasonably merged.
Marco van Hulten, Rob Middag, Jean-Claude Dutay, Hein de Baar, Matthieu Roy-Barman, Marion Gehlen, Alessandro Tagliabue, and Andreas Sterl
Biogeosciences, 14, 1123–1152,Short summary
We ran a global ocean model to understand manganese (Mn), a biologically essential element. Our model shows that (i) in the deep ocean, dissolved [Mn] is mostly homogeneous ~0.10—0.15 nM. The model reproduces this with a threshold on MnO2 of 25 pM, suggesting a minimal particle concentration is needed before aggregation and removal become efficient. (ii) The observed distinct hydrothermal signals are produced by assuming both a strong source and a strong removal of Mn near hydrothermal vents.
Laura Perrin, Ian Probert, Gerald Langer, and Giovanni Aloisi
Biogeosciences, 13, 5983–6001,Short summary
Coccolithophores are calcifying marine algae that play an important role in the oceanic carbon cycle. Deep niches of coccolithophores exist in the ocean and are poorly understood. Laboratory cultures with the coccolithophore Emiliania huxleyi were carried out to reproduce the environmental conditions (light–nutrient limitation) of a deep niche in the South Pacific Ocean. Physiological modelling of experimental results allows us to estimate the growth rates of coccolithophores in this niche.
Audrey Gimenez, Melika Baklouti, Sophie Bonnet, and Thierry Moutin
Biogeosciences, 13, 5103–5120,Short summary
In the context of the VAHINE mesocosm experiment in the Nouméa lagoon (New Caledonia), a 1-D vertical biogeochemical mechanistic model was used together with the in situ experiment to complement our comprehension of the planktonic ecosystem dynamics and the main biogeochemical carbon, nitrogen and phosphate fluxes. The model also showed the fate of fixed N2 by providing, over time, the proportion of diazotroph-derived nitrogen (DDN) in each compartment (mineral and organic) of the model.
Claudie Beaulieu, Harriet Cole, Stephanie Henson, Andrew Yool, Thomas R. Anderson, Lee de Mora, Erik T. Buitenhuis, Momme Butenschön, Ian J. Totterdell, and J. Icarus Allen
Biogeosciences, 13, 4533–4553,Short summary
Regime shifts have been suggested in the late 1970s and late 1980s in the Gulf of Alaska with important consequences for fisheries. Here we investigate the ability of a suite of ocean biogeochemical models of varying complexity to simulate these regime shifts. Our results demonstrate that ocean models can successfully simulate regime shifts in the Gulf of Alaska region, thereby improving our understanding of how changes in physical conditions are propagated from lower to upper trophic levels.
Zuo Xue, Ruoying He, Katja Fennel, Wei-Jun Cai, Steven Lohrenz, Wei-Jen Huang, Hanqin Tian, Wei Ren, and Zhengchen Zang
Biogeosciences, 13, 4359–4377,Short summary
In this study we used a state-of-the-science coupled physical–biogeochemical model to simulate and examine temporal and spatial variability of sea surface CO2 concentration in the Gulf of Mexico. Our model revealed the Gulf was a net CO2 sink with a flux of 1.11 ± 0.84 × 1012 mol C yr−1. We also found that biological uptake was the primary driver making the Gulf an overall CO2 sink and that the carbon flux in the northern Gulf was very susceptible to changes in river inputs.
Amiotte-Suchet, P., Aubert, D., Probst, J. L., Gauthier-Lafaye, F., Probst, A., Andreux, F., and Viville, D.: δ13C pattern of dissolved inorganic carbon in a small granitic catchment: the Strengbach case study (Vosges mountains, France), Chem. Geol., 159, 129–145, https://doi.org/10.1016/S0009-2541(99)00037-6, 1999.
Amundson, R. G. and Davidson, E. A.: Carbon-Dioxide and Nitrogenous Gases in the Soil Atmosphere, J. Geochem. Explor., 38, 13–41, https://doi.org/10.1016/0375-6742(90)90091-N, 1990.
Aufdenkampe, A. K., Mayorga, E., Raymond, P. A., Melack, J. M., Doney, S. C., Alin, S. R., Aalto, R. E., and Yoo, K.: Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere, Front. Ecol. Environ., 9, 53–60, https://doi.org/10.1890/100014, 2011.
Barth, J. A. C., Mader, M., Nenning, F., van Geldern, R., and Friese, K.: Stable isotope mass balances versus concentration differences of dissolved inorganic carbon – implications for tracing carbon turnover in reservoirs, Isot. Environ. Healt. S., 13, 1–14, https://doi.org/10.1080/10256016.2017.1282478, 2017.
Bastviken, D., Sundgren, I., Natchimuthu, S., Reyier, H., and Galfalk, M.: Technical Note: Cost-efficient approaches to measure carbon dioxide (CO2) fluxes and concentrations in terrestrial and aquatic environments using mini loggers, Biogeosciences, 12, 3849–3859, https://doi.org/10.5194/bg-12-3849-2015, 2015.
Billett, M. F., Palmer, S. M., Hope, D., Deacon, C., Storeton-West, R., Hargreaves, K. J., Flechard, C., and Fowler, D.: Linking land-atmosphere-stream carbon fluxes in a lowland peatland system, Global Biogeochem. Cy., 18, 1–12, 2004.
Bishop, K., Buffam, I., Erlandsson, M., Folster, J., Laudon, H., Seibert, J., and Temnerud, J.: Aqua Incognita: the unknown headwaters, Hydrol. Process., 22, 1239–1242, https://doi.org/10.1002/Hyp.7049, 2008.
Butman, D. and Raymond, P. A.: Significant efflux of carbon dioxide from streams and rivers in the United States, Nat. Geosci., 4, 839–842, https://doi.org/10.1038/Ngeo1294, 2011.
Campeau, A., Lapierre, J. F., Vachon, D., and del Giorgio, P. A.: Regional contribution of CO2 and CH4 fluxes from the fluvial network in a lowland boreal landscape of Quebec, Global Biogeochem. Cy., 28, 57–69, https://doi.org/10.1002/2013gb004685, 2014.
Catalan, N., Marce, R., Kothawala, D. N., and Tranvik, L. J.: Organic carbon decomposition rates controlled by water retention time across inland waters, Nat. Geosci., 9, 501–504, https://doi.org/10.1038/Ngeo2720, 2016.
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, https://doi.org/10.1007/S10021-006-9013-8, 2007.
Coplen, T. B.: Guidelines and recommended terms for expression of stable-isotope-ratio and gas-ratio measurement results, Rapid Commun. Mass Spectrom., 25, 2538–2560, https://doi.org/10.1002/rcm.5129, 2011.
Crawford, J. T., Striegl, R. G., Wickland, K. P., Dornblaser, M. M., and Stanley, E. H.: Emissions of carbon dioxide and methane from a headwater stream network of interior Alaska, J. Geophys. Res.-Biogeo., 118, 482–494, https://doi.org/10.1002/Jgrg.20034, 2013.
Davidson, E. A., Figueiredo, R. O., Markewitz, D., and Aufdenkampe, A. K.: Dissolved CO2 in small catchment streams of eastern Amazonia: A minor pathway of terrestrial carbon loss, J. Geophys. Res.-Biogeo., 115, 1–6, https://doi.org/10.1029/2009jg001202, 2010.
Demars, B. O. L., Manson, J. R., Olafsson, J. S., Gislason, G. M., Gudmundsdottir, R., Woodward, G., Reiss, J., Pichler, D. E., Rasmussen, J. J., and Friberg, N.: Temperature and the metabolic balance of streams, Freshwater Biol., 56, 1106–1121, https://doi.org/10.1111/j.1365-2427.2010.02554.x, 2011.
Dickson, A. G., Sabine, C. L., and Christian, J. R. (Eds.): Guide to best practices for ocean CO2 measurements, PICES Special Publication 3, 191 pp., available at: https://www.nodc.noaa.gov/ocads/oceans/Handbook_2007.html (last access: 25 December 2018), 2007.
Dinsmore, K. J. and Billett, M. F.: Continuous measurement and modeling of CO2 losses from a peatland stream during stormflow events, Water Resour. Res., 44, W12417, https://doi.org/10.1029/2008wr007284, 2008.
Dusek, J., Vogel, T., and Sanda, M.: Hillslope hydrograph analysis using synthetic and natural oxygen-18 signatures, J. Hydrol., 475, 415–427, 2012.
Earth System Research Laboratory: National Oceanic and Atmospheric Administration/Earth System Research Laboratory-Global Monitoring Division (ESRL/GMD), Global average marine surface annual mean CO2 data, ESRL/GMD, Boulder, Colorado, available at: http://www.esrl.noaa.gov/gmd/index.html, last access: 10 July 2017.
Ehleringer, J. R. and Cerling, T. E.: C3 and C4 Photosynthesis, in: Encyclopedia of Global Environmental Change, Volume 2, The Earth System: Biological and Ecological Dimensions of Global Environmental Change, edited by: Mooney, H. A. and Canadell, J. G., John Wiley & Sons, 186–190, 2002.
Gonzalez-Valencia, R., Magana-Rodriguez, F., Gerardo-Nieto, O., Sepulveda-Jauregui, A., Martinez-Cruz, K., Anthony, K. W., Baer, D., and Thalasso, F.: In Situ Measurement of Dissolved Methane and Carbon Dioxide in Freshwater Ecosystems by Off-Axis Integrated Cavity Output Spectroscopy, Environ. Sci. Technol., 48, 11421–11428, https://doi.org/10.1021/Es500987j, 2014.
Halbedel, S. and Koschorreck, M.: Regulation of CO2 emissions from temperate streams and reservoirs, Biogeosciences, 10, 7539–7551, https://doi.org/10.5194/Bg-10-7539-2013, 2013.
Hotchkiss, E. R., Hall, R. O., Sponseller, R. A., Butman, D., Klaminder, J., Laudon, H., Rosvall, M., and Karlsson, J.: Sources of and processes controlling CO2 emissions change with the size of streams and rivers, Nat. Geosci., 8, 696–699, https://doi.org/10.1038/NGEO2507, 2015.
Hrncir, M., Sanda, M., Kulasova, A., and Cislerova, M.: Runoff formation in a small catchment at hillslope and catchment scales, Hydrol. Process., 24, 2248–2256, 2010.
Humborg, C., Morth, C. M., Sundbom, M., Borg, H., Blenckner, T., Giesler, R., and Ittekkot, V.: CO2 supersaturation along the aquatic conduit in Swedish watersheds as constrained by terrestrial respiration, aquatic respiration and weathering, Glob. Change Biol., 16, 1966–1978, https://doi.org/10.1111/J.1365-2486.2009.02092.X, 2010.
Johnson, M. S., Lehmann, J., Riha, S. J., Krusche, A. V., Richey, J. E., Ometto, J. P. H. B., and Couto, E. G.: CO2 efflux from Amazonian headwater streams represents a significant fate for deep soil respiration, Geophys. Res. Lett., 35, 1–5, https://doi.org/10.1029/2008gl034619, 2008.
Johnson, M. S., Billett, M. F., Dinsmore, K. J., Wallin, M., Dyson, K. E., and Jassal, R. S.: Direct and continuous measurement of dissolved carbon dioxide in freshwater aquatic systems-method and applications, Ecohydrology, 3, 68–78, https://doi.org/10.1002/Eco.95, 2010.
Jones, J. B. and Mulholland, P. J.: Influence of drainage basin topography and elevation on carbon dioxide and methane supersaturation of stream water, Biogeochemistry, 40, 57–72, https://doi.org/10.1023/A:1005914121280, 1998.
Lauerwald, R., Laruelle, G. G., Hartmann, J., Ciais, P., and Regnier, P. A. G.: Spatial patterns in CO2 evasion from the global river network, Global Biogeochem. Cy., 29, 534–554, https://doi.org/10.1002/2014GB004941, 2015.
Lee, K. Y., van Geldern, R., and Barth, J. A. C.: A high-resolution carbon balance in a small temperate catchment: Insights from the Schwabach River, Germany, Appl. Geochem., 85, 86–96, https://doi.org/10.1016/j.apgeochem.2017.08.007, 2017.
Lorke, A., Bodmer, P., Noss, C., Alshboul, Z., Koschorreck, M., Somlai-Haase, C., Bastviken, D., Flury, S., McGinnis, D. F., Maeck, A., Muller, D., and Premke, K.: Technical note: drifting versus anchored flux chambers for measuring greenhouse gas emissions from running waters, Biogeosciences, 12, 7013–7024, https://doi.org/10.5194/bg-12-7013-2015, 2015.
Marx, A., Dusek, J., Jankovec, J., Sanda, M., Vogel, T., van Geldern, R., Hartmann, J., and Barth, J. A. C.: A review of CO2 and associated carbon dynamics in headwater streams: A global perspective, Rev. Geophys., 55, 560–585, https://doi.org/10.1002/2016RG000547, 2017a.
Marx, A., Hintze, S., Sanda, M., Jankovec, J., Oulehle, F., Dusek, J., Vogel, T., Vitvar, T., van Geldern, R., and Barth, J. A. C.: Acid rain footprint three decades after peak deposition: Long-term recovery from pollutant sulphate in the Uhlirska catchment (Czech Republic), Sci. Total. Env., 598, 1037–1049, https://doi.org/10.1016/j.scitotenv.2017.04.109, 2017b.
Marx, A., Conrad, M., Aizinger, V., Prechtel, A., van Geldern, R., and Barth, J. A. C.: Stream and groundwater chemistry of the Uhlirska catchment, Czech Republic, PANGAEA, https://doi.org/10.1594/PANGAEA.889689, 2018.
Mook, W. G., Bommerso, J. C., and Staverma, W. H.: Carbon Isotope Fractionation between Dissolved Bicarbonate and Gaseous Carbon-Dioxide, Earth Plan. Sc. Lett., 22, 169–176, https://doi.org/10.1016/0012-821x(74)90078-8, 1974.
Mook, W. G., Koopmans, M., Carter, A. F., and Keeling, C. D.: Seasonal, Latitudinal, and Secular Variations in the Abundance and Isotopic-Ratios of Atmospheric Carbon-Dioxide.1. Results from Land Stations, J. Geophys. Res.-Oc. Atm., 88, 915–933, https://doi.org/10.1029/Jc088ic15p10915, 1983.
Moran, M. A. and Zepp, R. G.: Role of photoreactions in the formation of biologically labile compounds from dissolved organic matter, Limnol. Oceanogr., 42, 1307–1316, 1997.
Myrttinen, A., Becker, V., and Barth, J. A. C.: A review of methods used for equilibrium isotope fractionation investigations between dissolved inorganic carbon and CO2, Earth-Sci. Rev., 115, 192–199, https://doi.org/10.1016/j.earscirev.2012.08.004, 2012.
Myrttinen, A., Becker, V., and Barth, J. A. C.: Corrigendum to “A review of methods used for equilibrium isotope fractionation investigations between dissolved inorganic carbon and CO2” (Earth Sci. Rev., 115, 192–199), Earth-Sci. Rev., 141, 178–178, https://doi.org/10.1016/j.earscirev.2014.11.009, 2015.
O'Leary, M. H.: Measurement of the isotope fractionation associated with diffusion of carbon dioxide in aqueous solution, J. Phys. Chem.-US, 88, 823–825, 1984.
Pacific, V. J., McGlynn, B. L., Riveros-Iregui, D. A., Welsch, D. L., and Epstein, H. E.: Variability in soil respiration across riparian-hillslope transitions, Biogeochemistry, 91, 51–70, https://doi.org/10.1007/s10533-008-9258-8, 2008.
Plummer, L. N. and Busenberg, E.: The Solubilities of Calcite, Aragonite and Vaterite in CO2-H2O Solutions between 0 and 90 ∘C, and an Evaluation of the Aqueous Model for the System CaCO3-CO2-H2O, Geochim. Cosmochim. Ac., 46, 1011–1040, https://doi.org/10.1016/0016-7037(82)90056-4, 1982.
Polsenaere, P. and Abril, G.: Modelling CO2 degassing from small acidic rivers using water pCO2, DIC and δ13C-DIC data, Geochim. Cosmochim. Ac., 91, 220–239, https://doi.org/10.1016/J.Gca.2012.05.030, 2012.
Polsenaere, P., Savoye, N., Etcheber, H., Canton, M., Poirier, D., Bouillon, S., and Abril, G.: Export and degassing of terrestrial carbon through watercourses draining a temperate podzolized catchment, Aquat. Sci., 75, 299–319, https://doi.org/10.1007/S00027-012-0275-2, 2013.
Raymond, P. A., Zappa, C. J., Butman, D., Bott, T. L., Potter, J., Mulholland, P., Laursen, A. E., McDowell, W. H., and Newbold, D.: Scaling the gas transfer velocity and hydraulic geometry in streams and small rivers, Limnol. Oceanogr.-Fluids Environ., 2, 41–53, https://doi.org/10.1215/21573689-1597669, 2012.
Raymond, P. A., Hartmann, J., Lauerwald, R., Sobek, S., McDonald, C., Hoover, M., Butman, D., Striegl, R., Mayorga, E., Humborg, C., Kortelainen, P., Durr, H., Meybeck, M., Ciais, P., and Guth, P.: Global carbon dioxide emissions from inland waters, Nature, 503, 355–359, https://doi.org/10.1038/Nature12760, 2013.
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.
Regnier, P., Friedlingstein, P., Ciais, P., Mackenzie, F. T., Gruber, N., Janssens, I. A., Laruelle, G. G., Lauerwald, R., Luyssaert, S., Andersson, A. J., Arndt, S., Arnosti, C., Borges, A. V., Dale, A. W., Gallego-Sala, A., Godderis, Y., Goossens, N., Hartmann, J., Heinze, C., Ilyina, T., Joos, F., LaRowe, D. E., Leifeld, J., Meysman, F. J. R., Munhoven, G., Raymond, P. A., Spahni, R., Suntharalingam, P., and Thullner, M.: Anthropogenic perturbation of the carbon fluxes from land to ocean, Nat. Geosci., 6, 597–607, https://doi.org/10.1038/ngeo1830, 2013.
Reichert, P., Uehlinger, U., and Acuna, V.: Estimating stream metabolism from oxygen concentrations: Effect of spatial heterogeneity, J. Geophys. Res.-Biogeo., 114, G03016, https://doi.org/10.1029/2008jg000917, 2009.
Sanda, M. and Cislerova, M.: Transforming Hydrographs in the Hillslope Subsurface, J. Hydrol. Hydromech., 57, 264–275, https://doi.org/10.2478/V10098-009-0023-Z, 2009.
Sanda, M., Vitvar, T., Kulasova, A., Jankovec, J., and Cislerova, M.: Run-off formation in a humid, temperate headwater catchment using a combined hydrological, hydrochemical and isotopic approach (Jizera Mountains, Czech Republic), Hydrol. Process., 28, 3217–3229, https://doi.org/10.1002/hyp.9847, 2014.
Sawakuchi, H. O., Neu, V., Ward, N. D., Barros, M. d. L. C., Valerio, A. M., Gagne-Maynard, W., Cunha, A. C., Less, D. F. S., Diniz, J. E. M., Brito, D. C., Krusche, A. V., and Richey, J. E.: Carbon Dioxide Emissions along the Lower Amazon River, Front. Mar. Sci., 4, 1–12, https://doi.org/10.3389/fmars.2017.00076, 2017.
Schelker, J., Singer, G. A., Ulseth, A. J., Hengsberger, S., and Battin, T. J.: CO2 evasion from a steep, high gradient stream network: importance of seasonal and diurnal variation in aquatic pCO2 and gas transfer, Limnol. Oceanogr., 61, 1826–1838, https://doi.org/10.1002/lno.10339, 2016.
St-Jean, G.: Automated quantitative and isotopic (13C) analysis of dissolved inorganic carbon and dissolved organic carbon in continuous-flow using a total organic carbon analyser, Rapid Commun. Mass Spectrom., 17, 419–428, https://doi.org/10.1002/rcm.926, 2003.
Stets, E. G., Butman, D., McDonald, C. P., Stackpoole, S. M., DeGrandpre, M. D., and Striegl, R. G.: Carbonate buffering and metabolic controls on carbon dioxide in rivers, Global Biogeochem. Cy., 31, 663–677, https://doi.org/10.1002/2016gb005578, 2017.
Teodoru, C. R., Del Giorgio, P. A., Prairie, Y. T., and Camire, M.: Patterns in pCO2 in boreal streams and rivers of northern Quebec, Canada, Global Biogeochem. Cy., 23, 1–11, https://doi.org/10.1029/2008gb003404, 2009.
Venkiteswaran, J. J., Schiff, S. L., and Wallin, M. B.: Large Carbon Dioxide Fluxes from Headwater Boreal and Sub-Boreal Streams, Plos One, 9, 1–9, https://doi.org/10.1371/journal.pone.0101756, 2014.
Vitvar, T., Sanda, M., Marx, A., Hubert, E., Jankovec, J., and Barth, J. A. C.: Hydrochemical and isotopic tracing of runoff generation in the small mountainous catchment Uhlirska (Czech Republic), using the NETPATH approach, Acta Hydrologica Slovaca, 17, 190–198, 2016.
Vogel, J. C.: Variability of Carbon Isotope Fractionation during Photosynthesis, in: Stable Isotopes and Plant Carbon-water Relations, edited by: Ehleringer, J. R., Hall, A. E., and Farquhar, G. D., Academic Press, San Diego, 29–46, ISBN 9780122333804, https://doi.org/10.1016/B978-0-08-091801-3.50010-6, 1993,
Wallin, M. B., Oquist, M. G., Buffam, I., Billett, M. F., Nisell, J., and Bishop, K. H.: Spatiotemporal variability of the gas transfer coefficient ( in boreal streams: Implications for large scale estimates of CO2 evasion, Global Biogeochem. Cy., 25, 1–14, https://doi.org/10.1029/2010gb003975, 2011.
Wehrli, B.: Biogeochemistry Conduits of the Carbon Cycle, Nature, 503, 346–347, 2013.
CO2 outgassing from small streams causes one of the main uncertainties in global carbon budgets. These are caused by variable flow conditions, changing stream surface areas, and groundwater seeps. Here we used groundwater data to improve a novel stable carbon isotope modelling approach. We found that CO2 outgassing contributed more than three-fourths of annual stream inorganic carbon loss in a small, silicate catchment. We underline the potential of this approach for global applications.
CO2 outgassing from small streams causes one of the main uncertainties in global carbon budgets....