Articles | Volume 16, issue 2
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Modeling oceanic nitrate and nitrite concentrations and isotopes using a 3-D inverse N cycle model
Taylor S. Martin
Department of Earth System Science, Stanford University, Stanford, CA, USA
Department of Earth System Science, University of California, Irvine, Irvine, CA, USA
Karen L. Casciotti
Department of Earth System Science, Stanford University, Stanford, CA, USA
No articles found.
Colette L. Kelly, Nicole M. Travis, Pascale A. Baya, Claudia Frey, Xin Sun, Bess B. Ward, and Karen L. Casciotti
We investigated the origins of nitrous oxide, a potent greenhouse gas, in low oxygen ocean regions. Our findings shed light on the microbial processes behind nitrous oxide production, including “hybrid” nitrous oxide generation by ammonia-oxidizing archaea, one of the most abundant organisms in the ocean. We also observed a strong link between nitrous oxide production and oxygen levels. These results set up potential feedbacks between oxygen depletion and greenhouse gas cycling in the oceans.
Luke Skinner, Francois Primeau, Aurich Jeltsch-Thömmes, Fortunat Joos, Peter Köhler, and Edouard Bard
Clim. Past, 19, 2177–2202,Short summary
Radiocarbon is best known as a dating tool, but it also allows us to track CO2 exchange between the ocean and atmosphere. Using decades of data and novel mapping methods, we have charted the ocean’s average radiocarbon ″age” since the last Ice Age. Combined with climate model simulations, these data quantify the ocean’s role in atmospheric CO2 rise since the last Ice Age while also revealing that Earth likely received far more cosmic radiation during the last Ice Age than hitherto believed.
Benoît Pasquier, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau
Biogeosciences, 20, 2985–3009,Short summary
Modeling the ocean's carbon and oxygen cycles accurately is challenging. Parameter optimization improves the fit to observed tracers but can introduce artifacts in the biological pump. Organic-matter production and subsurface remineralization rates adjust to compensate for circulation biases, changing the pathways and timescales with which nutrients return to the surface. Circulation biases can thus strongly alter the system’s response to ecological change, even when parameters are optimized.
Wei-Lei Wang, Guisheng Song, François Primeau, Eric S. Saltzman, Thomas G. Bell, and J. Keith Moore
Biogeosciences, 17, 5335–5354,Short summary
Dimethyl sulfide, a volatile compound produced as a byproduct of marine phytoplankton activity, can be emitted to the atmosphere via gas exchange. In the atmosphere, DMS is oxidized to cloud condensation nuclei, thus contributing to cloud formation. Therefore, oceanic DMS plays an important role in regulating the planet's climate by influencing the radiation budget. In this study, we use an artificial neural network model to update the global DMS climatology and estimate the sea-to-air flux.
Allison R. Moreno, George I. Hagstrom, Francois W. Primeau, Simon A. Levin, and Adam C. Martiny
Biogeosciences, 15, 2761–2779,Short summary
To bridge the missing links between variable marine elemental stoichiometry, phytoplankton physiology and carbon cycling, we embed four environmentally controlled stoichiometric models into a five-box ocean model. As predicted each model varied in its influence on the biological pump. Surprisingly, we found that variation can lead to nonlinear controls on atmospheric CO2 and carbon export, suggesting the need for further studies of ocean C : P and the impact on ocean carbon cycling.
Weilei Wang, Cindy Lee, and Francois Primeau
Revised manuscript not acceptedShort summary
We introduce a new model that can infer particle dynamics rate constants using large volume pump chloropigment data. We compare the inferred rate constants to those estimated using the same tracers but collected using sinking velocity (SV) sediment traps, and to those estimated using SV trap thorium data. We conclude that the two different sampling methods have less influence on particle aggregation and disaggregation rate constant estimations than do the two different tracers themselves.
R. T. Letscher, J. K. Moore, Y.-C. Teng, and F. Primeau
Biogeosciences, 12, 209–221,Short summary
Marine DOM is known to exhibit stoichiometry depleted in N and P compared with POM, suggesting variable production and remineralization stoichiometry for C, N, and P within marine DOM cycling. We utilize marine DOM observations and an inverse tracer modeling framework to optimize DOM cycling parameters for the BEC biogeochemistry ocean model of the CESM, finding a variable stoichiometry with faster turnover of P > N > C superior to the commonly assumed Redfield stoichiometry for marine DOM.
T. DeVries, C. Deutsch, P. A. Rafter, and F. Primeau
Biogeosciences, 10, 2481–2496,
Related subject area
Biogeochemistry: Modelling, AquaticSeasonal and interannual variability of the pelagic ecosystem and of the organic carbon budget in the Rhodes Gyre (eastern Mediterranean): influence of winter mixingHow much do bacterial growth properties and biodegradable dissolved organic matter control water quality at low flow?Methane emissions from Arctic landscapes during 2000–2015: an analysis with land and lake biogeochemistry modelsIncluding filter-feeding gelatinous macrozooplankton in a global marine biogeochemical model: model–data comparison and impact on the ocean carbon cycleRiverine impact on future projections of marine primary production and carbon uptakeSubsurface oxygen maximum in oligotrophic marine ecosystems: mapping the interaction between physical and biogeochemical processesQuantifying biological carbon pump pathways with a data-constrained mechanistic model ensemble approachAssessing the spatial and temporal variability of methylmercury biogeochemistry and bioaccumulation in the Mediterranean Sea with a coupled 3D modelHydrodynamic and biochemical impacts on the development of hypoxia in the Louisiana–Texas shelf – Part 2: statistical modeling and hypoxia predictionModelling the effects of benthic fauna on carbon, nitrogen and phosphorus dynamics in the Baltic SeaImproved prediction of dimethyl sulfide (DMS) distributions in the northeast subarctic Pacific using machine-learning algorithmsNutrient transport and transformation in macrotidal estuaries of the French Atlantic coast: a modeling approach using the Carbon-Generic Estuarine ModelA modelling study of temporal and spatial pCO2 variability on the biologically active and temperature-dominated Scotian ShelfModeling 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 studyRole 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 OceanBiogeochemical 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 oceanGroundwater data improve modelling of headwater stream CO2 outgassing with a stable DIC isotope approachThe 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 forcing
Joelle Habib, Caroline Ulses, Claude Estournel, Milad Fakhri, Patrick Marsaleix, Mireille Pujo-Pay, Marine Fourrier, Laurent Coppola, Alexandre Mignot, Laurent Mortier, and Pascal Conan
Biogeosciences, 20, 3203–3228,Short summary
The Rhodes Gyre, eastern Mediterranean Sea, is the main Levantine Intermediate Water formation site. In this study, we use a 3D physical–biogeochemical model to investigate the seasonal and interannual variability of organic carbon dynamics in the gyre. Our results show its autotrophic nature and its high interannual variability, with enhanced primary production, downward exports, and onward exports to the surrounding regions during years marked by intense heat losses and deep mixed layers.
Masihullah Hasanyar, Thomas Romary, Shuaitao Wang, and Nicolas Flipo
Biogeosciences, 20, 1621–1633,Short summary
The results of this study indicate that biodegradable dissolved organic matter is responsible for oxygen depletion at low flow during summer seasons when heterotrophic bacterial activity is so intense. Therefore, the dissolved organic matter must be well measured in the water monitoring networks in order to have more accurate water quality models. It also advocates for high-frequency data collection for better quantification of the uncertainties related to organic matter.
Xiangyu Liu and Qianlai Zhuang
Biogeosciences, 20, 1181–1193,Short summary
We are among the first to quantify methane emissions from inland water system in the pan-Arctic. The total CH4 emissions are 36.46 Tg CH4 yr−1 during 2000–2015, of which wetlands and lakes were 21.69 Tg yr−1 and 14.76 Tg yr−1, respectively. By using two non-overlap area change datasets with land and lake models, our simulation avoids small lakes being counted twice as both lake and wetland, and it narrows the gap between two different methods used to quantify regional CH4 emissions.
Corentin Clerc, Laurent Bopp, Fabio Benedetti, Meike Vogt, and Olivier Aumont
Biogeosciences, 20, 869–895,Short summary
Gelatinous zooplankton play a key role in the ocean carbon cycle. In particular, pelagic tunicates, which feed on a wide size range of prey, produce rapidly sinking detritus. Thus, they efficiently transfer carbon from the surface to the depths. Consequently, we added these organisms to a marine biogeochemical model (PISCES-v2) and evaluated their impact on the global carbon cycle. We found that they contribute significantly to carbon export and that this contribution increases with depth.
Shuang Gao, Jörg Schwinger, Jerry Tjiputra, Ingo Bethke, Jens Hartmann, Emilio Mayorga, and Christoph Heinze
Biogeosciences, 20, 93–119,Short summary
We assess the impact of riverine nutrients and carbon (C) on projected marine primary production (PP) and C uptake using a fully coupled Earth system model. Riverine inputs alleviate nutrient limitation and thus lessen the projected PP decline by up to 0.7 Pg C yr−1 globally. The effect of increased riverine C may be larger than the effect of nutrient inputs in the future on the projected ocean C uptake, while in the historical period increased nutrient inputs are considered the largest driver.
Valeria Di Biagio, Stefano Salon, Laura Feudale, and Gianpiero Cossarini
Biogeosciences, 19, 5553–5574,Short summary
The amount of dissolved oxygen in the ocean is the result of interacting physical and biological processes. Oxygen vertical profiles show a subsurface maximum in a large part of the ocean. We used a numerical model to map this subsurface maximum in the Mediterranean Sea and to link local differences in its properties to the driving processes. This emerging feature can help the marine ecosystem functioning to be better understood, also under the impacts of climate change.
Michael R. Stukel, Moira Décima, and Michael R. Landry
Biogeosciences, 19, 3595–3624,Short summary
The biological carbon pump (BCP) transports carbon into the deep ocean, leading to long-term marine carbon sequestration. It is driven by many physical, chemical, and ecological processes. We developed a model of the BCP constrained using data from 11 cruises in 4 different ocean regions. Our results show that sinking particles and vertical mixing are more important than transport mediated by vertically migrating zooplankton. They also highlight the uncertainty in current estimates of the BCP.
Ginevra Rosati, Donata Canu, Paolo Lazzari, and Cosimo Solidoro
Biogeosciences, 19, 3663–3682,Short summary
Methylmercury (MeHg) is produced and bioaccumulated in marine food webs, posing concerns for human exposure through seafood consumption. We modeled and analyzed the fate of MeHg in the lower food web of the Mediterranean Sea. The modeled spatial–temporal distribution of plankton bioaccumulation differs from the distribution of MeHg in surface water. We also show that MeHg exposure concentrations in temperate waters can be lowered by winter convection, which is declining due to climate change.
Yanda Ou, Bin Li, and Z. George Xue
Biogeosciences, 19, 3575–3593,Short summary
Over the past decades, the Louisiana–Texas shelf has been suffering recurring hypoxia (dissolved oxygen < 2 mg L−1). We developed a novel prediction model using state-of-the-art statistical techniques based on physical and biogeochemical data provided by a numerical model. The model can capture both the magnitude and onset of the annual hypoxia events. This study also demonstrates that it is possible to use a global model forecast to predict regional ocean water quality.
Eva Ehrnsten, Oleg Pavlovitch Savchuk, and Bo Gustav Gustafsson
Biogeosciences, 19, 3337–3367,Short summary
We studied the effects of benthic fauna, animals living on or in the seafloor, on the biogeochemical cycles of carbon, nitrogen and phosphorus using a model of the Baltic Sea ecosystem. By eating and excreting, the animals transform a large part of organic matter sinking to the seafloor into inorganic forms, which fuel plankton blooms. Simultaneously, when they move around (bioturbate), phosphorus is bound in the sediments. This reduces nitrogen-fixing plankton blooms and oxygen depletion.
Brandon J. McNabb and Philippe D. Tortell
Biogeosciences, 19, 1705–1721,Short summary
The trace gas dimethyl sulfide (DMS) plays an important role in the ocean sulfur cycle and can also influence Earth’s climate. Our study used two statistical methods to predict surface ocean concentrations and rates of sea–air exchange of DMS in the northeast subarctic Pacific. Our results show improved predictive power over previous approaches and suggest that nutrient availability, light-dependent processes, and physical mixing may be important controls on DMS in this region.
Xi Wei, Josette Garnier, Vincent Thieu, Paul Passy, Romain Le Gendre, Gilles Billen, Maia Akopian, and Goulven Gildas Laruelle
Biogeosciences, 19, 931–955,Short summary
Estuaries are key reactive ecosystems along the land–ocean aquatic continuum and are often strongly impacted by anthropogenic activities. We calculated nutrient in and out fluxes by using a 1-D transient model for seven estuaries along the French Atlantic coast. Among these, large estuaries with high residence times showed higher retention rates than medium and small ones. All reveal coastal eutrophication due to the excess of diffused nitrogen from intensive agricultural river basins.
Krysten Rutherford, Katja Fennel, Dariia Atamanchuk, Douglas Wallace, and Helmuth Thomas
Biogeosciences, 18, 6271–6286,Short 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.
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.
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.
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.
Anne Marx, Marcus Conrad, Vadym Aizinger, Alexander Prechtel, Robert van Geldern, and Johannes A. C. Barth
Biogeosciences, 15, 3093–3106,Short summary
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.
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.
Anderson, J. J., Okubo, A., Robbins, A. S., and Richards, F. A.: A model for nitrate distributions in oceanic oxygen minimum zones, Deep-Sea Res., 29, 1113–1140, https://doi.org/10.1016/0198-0149(82)90031-0, 1982.
Babbin, A. R., Keil, R. G., Devol, A. H., and Ward, B. B.: Organic Matter Stoichiometry, Flux, and Oxygen Control Nitrogen Loss in the Ocean, Science, 344, 406–408, https://doi.org/10.1126/science.1248364, 2014.
Babbin, A. R., Peters, B. D., Mordy, C. W., Widner, B., Casciotti, K. L., and Ward, B. B.: Multiple metabolisms constrain the anaerobic nitrite budget in the Eastern Tropical South Pacific, Global Biogeochem. Cy., 31, 258–271, https://doi.org/10.1002/2016GB005407, 2017.
Berelson, W. M.: Particle settling rates increase with depth in the ocean, Deep-Sea Res. Pt. II, 49, 237–251, https://doi.org/10.1016/S0967-0645(01)00102-3, 2002.
Bianchi, D., Dunne, J. P., Sarmiento, J. L., and Galbraith, E. D.: Data-based estimates of suboxia, denitrification, and N2O production in the ocean and their sensitivities to dissolved O2, Global Biogeochem. Cy., 26, 1–13, https://doi.org/10.1029/2011GB004209, 2012.
Bohlen, L., Dale, A. W., and Wallmann, K.: Simple transfer functions for calculating benthic fixed nitrogen losses and regeneration ratios in global biogeochemical models, Global Biogeochem. Cy., 26, GB3029, https://doi.org/10.1029/2011GB004198, 2012.
Bonin, P., Gilewicz, M., and Bertrand, J. C.: Effects of oxygen on each step of denitrification on Pseudomonas nautica, Can. J. Microbiol., 35, 1061–1064, https://doi.org/10.1139/m89-177, 1989.
Bourbonnais, A., Altabet, M. A., Charoenpong, C. N., Larkum, J., Hu, H., Bange, H. W., and Stramma, L.: N-loss isotope effects in the Peru oxygen minimum zone studied using a mesoscale eddy as a natural tracer experiment, Global Biogeochem. Cy., 29, 793–811, https://doi.org/10.1002/2013GB004679, 2015.
Brandes, J. A. and Devol, A. H.: Isotopic fractionation of oxygen and nitrogen in coastal marine sediments, Geochim. Cosmochim. Ac., 61, 1793–1801, https://doi.org/10.1016/S0016-7037(97)00041-0, 1997.
Brandes, J. A. and Devol, A. H.: A global marine-fixed nitrogen isotopic budget: Implications for Holocene nitrogen cycling, Global Biogeochem. Cy., 16, 67-1–67-14, https://doi.org/10.1029/2001GB001856, 2002.
Bristow, L. A., Dalsgaard, T., Tiano, L., Mills, D. B., Bertagnolli, A. D., Wright, J. J., Hallam, S. J., Ulloa, O., Canfield, D. E., Revsbech, N. P., and Thamdrup, B.: Ammonium and nitrite oxidation at nanomolar oxygen concentrations in oxygen minimum zone waters, P. Natl. Acad. Sci. USA, 113, 10601–10606, https://doi.org/10.1073/pnas.1600359113, 2016.
Bristow, L. A., Callbeck, C. M., Larsen, M., Altabet, M. A., Dekaezemacker, J., Forth, M., Gauns, M., Glud, R. N., Kuypers, M. M. M., Lavik, G., Milucka, J., Naqvi, S. W. A., Pratihary, A., Revsbech, N. P., Thamdrup, B., Treusch, A. H., and Canfield, D. E.: N2 production rates limited by nitrite availability in the Bay of Bengal oxygen minimum zone, Nat. Geosci., 10, 24–29, https://doi.org/10.1038/ngeo2847, 2017.
Brown, Z. W., Casciotti, K. L., Pickart, R. S., Swift, J. H., and Arrigo, K. R.: Aspects of the marine nitrogen cycle of the Chukchi Sea shelf and Canada Basin, Deep-Sea Res. Pt. II, 118, 73–87, https://doi.org/10.1016/j.dsr2.2015.02.009, 2015.
Brunner, B., Contreras, S., Lehmann, M. F., Matantseva, O., Rollog, M., Kalvelage, T., Klockgether, G., Lavik, G., Jetten, M. S. M., Kartal, B., and Kuypers, M. M. M.: Nitrogen isotope effects induced by anammox bacteria, P. Natl. Acad. Sci. USA, 110, 18994–18999, https://doi.org/10.1073/pnas.1310488110, 2013.
Bryan, B. A., Shearer, G., Skeeters, J. L., and Kohl, D. H.: Variable expression of the nitrogen isotope effect associated with denitrification of nitrite, J. Biol. Chem., 258, 8613–8617, 1983.
Buchwald, C. and Casciotti, K. L.: Oxygen isotopic fractionation and exchange during bacterial nitrite oxidation, Limnol. Oceanogr., 55, 1064–1074, https://doi.org/10.4319/lo.2010.55.3.1064, 2010.
Buchwald, C., Santoro, A. E., Stanley, R. H. R., and Casciotti, K. L.: Nitrogen cycling in the secondary nitrite maximum of the eastern tropical North Pacific off Costa Rica, Global Biogeochem. Cy., 29, 2061–2081, https://doi.org/10.1002/2015GB005187, 2015.
Buesseler, K. O. and Boyd, P. W.: Shedding light on processes that control particle export and flux attenuation in the twilight zone of the open ocean, Limnol. Oceanogr., 54, 1210–1232, https://doi.org/10.4319/lo.2009.54.4.1210, 2009.
Buesseler, K. O., Trull, T. W., Steinberg, D. K., Silver, M. W., Siegel, D. A., Saitoh, S.-I., Lamborg, C. H., Lam, P. J., Karl, D. M., Jiao, N. Z., Honda, M. C., Elskens, M., Dehairs, F., Brown, S. L., Boyd, P. W., Bishop, J. K. B., and Bidigare, R. R.: VERTIGO (VERtical Transport In the Global Ocean): A study of particle sources and flux attenuation in the North Pacific, Deep-Sea Res. Pt. II, 55, 1522–1539, https://doi.org/10.1016/j.dsr2.2008.04.024, 2008.
Canfield, D. E.: Models of oxic respiration, denitrification and sulfate reduction in zones of coastal upwelling, Geochim. Cosmochim. Ac., 70, 5753–5765, https://doi.org/10.1016/j.gca.2006.07.023, 2006.
Capone, D. G., Burns, J. A., Montoya, J. P., Subramaniam, A., Mahaffey, C., Gunderson, T., Michaels, A. F., and Carpenter, E. J.: Nitrogen fixation by Trichodesmium spp.: An important source of new nitrogen to the tropical and subtropical North Atlantic Ocean, Global Biogeochem. Cy., 19, GB2024, https://doi.org/10.1029/2004GB002331, 2005.
Carpenter, E. J., Harvey, H. R., Brian, F., and Capone, D. G.: Biogeochemical tracers of the marine cyanobacterium Trichodesmium, Deep-Sea Res. Pt. I, 44, 27–38, https://doi.org/10.1016/S0967-0637(96)00091-X, 1997.
Casciotti, K. L.: Inverse kinetic isotope fractionation during bacterial nitrite oxidation, Geochim. Cosmochim. Ac., 73, 2061–2076, https://doi.org/10.1016/j.gca.2008.12.022, 2009.
Casciotti, K. L., Trull, T. W., Glover, D. M., and Davies, D.: Constraints on nitrogen cycling at the subtropical North Pacific Station ALOHA from isotopic measurements of nitrate and particulate nitrogen, Deep-Sea Res. Pt. II, 55, 1661–1672, https://doi.org/10.1016/j.dsr2.2008.04.017, 2008.
Casciotti, K. L., Buchwald, C., and McIlvin, M.: Implications of nitrate and nitrite isotopic measurements for the mechanisms of nitrogen cycling in the Peru oxygen deficient zone, Deep-Sea Res. Pt. I, 80, 78–93, https://doi.org/10.1016/j.dsr.2013.05.017, 2013.
Chavez, F. P. and Messié, M.: A comparison of Eastern Boundary Upwelling Ecosystems, Prog. Oceanogr., 83, 80–96, https://doi.org/10.1016/j.pocean.2009.07.032, 2009.
Chien, C.-T., Mackey, K. R. M., Dutkiewicz, S., Mahowald, N. M., Prospero, J. M., and Paytan, A.: Effects of African dust deposition on phytoplankton in the western tropical Atlantic Ocean off Barbados, Global Biogeochem. Cy., 30, 716–734, https://doi.org/10.1002/2015GB005334, 2016.
Codispoti, L. A.: Phosphorus vs. Nitrogen limitation of new and export production, in: Productivity of the Oceans: Present and Past, Vol. 44, John Wiley & Sons Ltd., New York City, NY, USA, 377–394, 1989.
Codispoti, L. A. and Christensen, J. P.: Nitrification, denitrification and nitrous oxide cycling in the eastern tropical South Pacific ocean, Mar. Chem., 16, 277–300, https://doi.org/10.1016/0304-4203(85)90051-9, 1985.
Codispoti, L. A., Friederich, G. E., Packard T. T., Glover, H. E., Kelly, P. J., Spinrad, R. W., Barber, R. T., Elkins, J. W., Ward, B. B., Lipschultz, F., and Lostaunau, N.: High Nitrite Levels off Northern Peru: A Signal of Instability in the Marine Denitrification Rate, Science, 233, 1200–1202, https://doi.org/10.1126/science.233.4769.1200, 1986.
Codispoti, L. A., Brandes, J. A., Christensen, J. P., Devol, A. H., Naqvi, S. W. A., Paerl, H. W., and Yoshinari, T.: The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 80–105, https://doi.org/10.3989/scimar.2001.65s285, 2001.
Dalsgaard, T., Stewart, F. J., Thamdrup, B., De Brabandere, L., Revsbech, N. P., Ulloa, O., Canfield, D. E., and DeLong, E. F.: Oxygen at nanomolar levels reversibly suppresses process rates and gene expression in anammox and denitrification in the oxygen minimum zone off Northern Chile, MBio, 5, e01966-14, https://doi.org/10.1128/mBio.01966-14, 2014.
Dentener, F., Drevet, J., Lamarque, J. F., Bey, I., Eickhout, B., Fiore, A. M., Hauglustaine, D., Horowitz, L. W., Krol, M., Kulshrestha, U. C., Lawrence, M., Galy-Lacaux, C., Rast, S., Shindell, D., Stevenson, D., Van Noije, T., Atherton, C., Bell, N., Bergman, D., Butler, T., Cofala, J., Collins, B., Doherty, R., Ellingsen, K., Galloway, J., Gauss, M., Montanaro, V., Müller, J. F., Pitari, G., Rodriguez, J., Sanderson, M., Solmon, F., Strahan, S., Schultz, M., Sudo, K., Szopa, S., and Wild, O.: Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation, Global Biogeochem. Cy., 20, GB4003, https://doi.org/10.1029/2005GB002672, 2006.
Deutsch, C., Gruber, N., Key, R. M., Sarmiento, J. L., and Ganachaud, A.: Denitrification and N2 fixation in the Pacific Ocean, Global Biogeochem. Cy., 15, 483–506, https://doi.org/10.1029/2000GB001291, 2001.
Deutsch, C., Sarmiento, J. L., Sigman, D. M., Gruber, N., and Dunne, J. P.: Spatial coupling of nitrogen inputs and losses in the ocean, Nature, 445, 163–167, https://doi.org/10.1038/nature05392, 2007.
DeVries, T. and Primeau, F.: Dynamically and Observationally Constrained Estimates of Water-Mass Distributions and Ages in the Global Ocean, J. Phys. Oceanogr., 41, 2381–2401, https://doi.org/10.1175/JPO-D-10-05011.1, 2011.
DeVries, T., Deutsch, C., Primeau, F., Chang, B., and Devol, A.: Global rates of water-column denitrification derived from nitrogen gas measurements, Nat. Geosci., 5, 547–550, https://doi.org/10.1038/ngeo1515, 2012.
DeVries, T., Deutsch, C., Rafter, P. A., and Primeau, F.: Marine denitrification rates determined from a global 3-D inverse model, Biogeosciences, 10, 2481–2496, https://doi.org/10.5194/bg-10-2481-2013, 2013.
Dunne, J. P., Armstrong, R. A., Gnanadesikan, A., and Sarmiento, J. L.: Empirical and mechanistic models for the particle export ratio, Global Biogeochem. Cy., 19, GB4026, https://doi.org/10.1029/2004GB002390, 2005.
Follows, M. J., Dutkiewicz, S., Grant, S., and Chisholm, S. W.: Emergent Biogeography of Microbial Communities in a Model Ocean, Science, 315, 1843–1846, https://doi.org/10.1126/science.1138544, 2007.
Frey, C., Hietanen, S., Jürgens, K., Labrenz, M., and Voss, M.: N and O isotope fractionation in nitrate during chemolithoautotrophic denitrification by Sulfurimonas gotlandica, Environ. Sci. Technol., 48, 13229–13237, https://doi.org/10.1021/es503456g, 2014.
Fuchsman, C. A., Devol, A. H., Casciotti, K. L., Buchwald, C., Chang, B. X., and Horak, R. E. A.: An N isotopic mass balance of the Eastern Tropical North Pacific Oxygen Deficient Zone, Deep-Sea Res. Pt. II, 156, 137–147, https://doi.org/10.1016/j.dsr2.2017.12.013, 2017.
Galloway, J. N., Dentener, F. J., Capone, D. G., Boyer, E. W., Howarth, R. W., Seitzinger, S. P., Asner, G. P., Cleveland, C. C., Green, P. A., Holland, E. A., Karl, D. M., Michaels, A. F., Porter, J. H., Townsend, A. R., and Vörösmarty, C. J.: Nitrogen cycles: past, present, and future, Biogeochemistry, 70, 153–226, https://doi.org/10.1007/s10533-004-0370-0, 2004.
Garcia, H. E., Boyer, T. P., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Mishonov, A. V., Baranova, O. K., Zweng, M. M., Reagan, J. R., and Johnson, D. R.: World Ocean Atlas 2013, Volume 3: dissolved oxygen, apparent oxygen utilization, and oxygen saturation, NOAA Atlas NESDIS 75, Silver Spring, MD, USA, 27 pp., 2013a.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Baranova, O. K., Zweng, M. M., Reagan, J. R., and Johnson, D. R.: World Ocean Atlas 2013, Volume 4: Dissolved inorganic nutrients (phosphate, nitrate, silicate), NOAA Atlas NESDIS 76, Silver Spring, MD, USA, 25 pp., 2013b.
Gaye, B., Nagel, B., Dähnke, K., Rixen, T., and Emeis, K-C.: Evidence of parallel denitrification and nitrite oxidation in the ODZ of the Arabian Sea from paired stable isotopes of nitrate and nitrite. Global Biogeochem. Cy., 27, 1059–1071, https://doi.org/10.1002/2011GB004115, 2013.
Granger, J., Sigman, D. M., Lehmann, M. F., and Tortell, P. D.: Nitrogen and oxygen isotope fractionation during dissimilatory nitrate reduction by denitrifying bacteria, Limnol. Oceanogr., 53, 2533–2545, https://doi.org/10.4319/lo.2008.53.6.2533, 2008.
Granger, J., Sigman, D. M., Rohde, M. M., Maldonado, M. T., and Tortell, P. D.: N and O isotope effects during nitrate assimilation by unicellular prokaryotic and eukaryotic plankton cultures, Geochim. Cosmochim. Ac., 74, 1030–1040, https://doi.org/10.1016/j.gca.2009.10.044, 2010.
Granger, J., Prokopenko, M. G., Sigman, D. M., Mordy, C. W., Morse, Z. M., Morales, L. V., Sambrotto, R. N., and Plessen, B.: Coupled nitrification-denitrification in sediment of the eastern Bering Sea shelf leads to 15N enrichment of fixed N in shelf waters, J. Geophys. Res.-Oceans, 116, 1–18, https://doi.org/10.1029/2010JC006751, 2011.
Gruber, N.: The Dynamics of the Marine Nitrogen Cycle and its Influence on Atmospheric CO2 Variations, in: The Ocean Carbon Cycle and Climate, Springer, the Netherlands, 2004.
Gruber, N.: The Marine Nitrogen Cycle: Overview and Challenges, in: Nitrogen in the Marine Environment, edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and Carpenter, E. J., Elsevier, Amsterdam, the Netherlands, 2008.
Gruber, N. and Galloway, J. N.: An Earth-system perspective of the global nitrogen cycle, Nature, 451, 293–296, https://doi.org/10.1038/nature06592, 2008.
Gruber, N. and Sarmiento, J. L.: Global patterns of marine nitrogen fixation and denitrification, Global Biogeochem. Cy., 11, 235–266, https://doi.org/10.1029/97GB00077, 1997.
Harding, K., Turk-Kubo, K. A., Sipler, R. E., Mills, M. M., Bronk, D. A., and Zehr, J. P.: Symbiotic unicellular cyanobacteria fix nitrogen in the Arctic Ocean, P. Natl. Acad. Sci. USA, 115, 13371–13375, https://doi.org/10.1073/pnas.1813658115, 2018.
Hastings, M. G., Jarvis, J. C., and Steig, E. J.: Anthropogenic Impacts on Nitrogen Isotopes of Ice-Core Nitrate, Science, 324, 1288, https://doi.org/10.1126/science.1170510, 2009.
Hoering, T. C. and Ford, H. T.: The Isotope Effect in the Fixation of Nitrogen by Azotobacter, J. Am. Chem. Soc., 82, 376–378, https://doi.org/10.1021/ja01487a031, 1960.
Holl, C. M. and Montoya, J. P.: Interactions between nitrate uptake and nitrogen fixation in continuous cultures of the marine diazotroph Trichodesmium (Cyanobacteria), J. Phycol., 41, 1178–1183, https://doi.org/10.1111/j.1529-8817.2005.00146.x, 2005.
Hu, H., Bourbonnais, A., Larkum, J., Bange, H. W., and Altabet, M. A.: Nitrogen cycling in shallow low-oxygen coastal waters off Peru from nitrite and nitrate nitrogen and oxygen isotopes, Biogeosciences, 13, 1453–1468, https://doi.org/10.5194/bg-13-1453-2016, 2016.
Jensen, M. M., Kuypers, M. M. M., Lavik, G., and Thamdrup, B.: Rates and regulation of anaerobic ammonium oxidation and denitrification in the Black Sea, Limnol. Oceanogr., 53, 23–36, https://doi.org/10.4319/lo.2008.53.1.0023, 2008.
Kalvelage, T., Jensen, M. M., Contreras, S., Revsbech, N. P., Lam, P., Günter, M., LaRoche, J., Lavik, G., and Kuypers, M. M. M.: Oxygen Sensitivity of Anammox and Coupled N-Cycle Processes in Oxygen Minimum Zones, PLoS One, 6, e29299, https://doi.org/10.1371/journal.pone.0029299, 2011.
Kalvelage, T., Lavik, G., Lam, P., Contreras, S., Arteaga, L., Loscher, C. R., Oschlies, A., Paulmier, A., Stramma, L., and Kuypers, M. M. M.: Nitrogen cycling driven by organic matter export in the South Pacific oxygen minimum zone, Nat. Geosci., 6, 228–234, https://doi.org/10.1038/ngeo1739, 2013.
Knapp, A. N., DiFiore, P. J., Deutsch, C., Sigman, D. M., and Lipschultz, F.: Nitrate isotopic composition between Bermuda and Puerto Rico: Implications for N2 fixation in the Atlantic Ocean, Global Biogeochem. Cy., 22, GB3014, https://doi.org/10.1029/2007GB003107, 2008.
Knapp, A. N., Sigman, D. M., Lipschultz, F., Kustka, A. B., and Capone, D. G.: Interbasin isotopic correspondence between upper-ocean bulk DON and subsurface nitrate and its implications for marine nitrogen cycling, Global Biogeochem. Cy., 25, GB4004, https://doi.org/10.1029/2010GB003878, 2011.
Kritee, K., Sigman, D. M., Granger, J., Ward, B. B., Jayakumar, A., and Deutsch, C.: Reduced isotope fractionation by denitrification under conditions relevant to the ocean, Geochim. Cosmochim. Ac., 92, 243–259, https://doi.org/10.1016/j.gca.2012.05.020, 2012.
Kuypers, M. M. M., Lavik, G., Woebken, D., Schmid, M., Fuchs, B. M., Amann, R., Jorgensen, B. B., and Jetten, M. S. M.: Massive nitrogen loss from the Benguela upwelling system through anaerobic ammonium oxidation, P. Natl. Acad. Sci. USA, 102, 6478–6483, https://doi.org/10.1073/pnas.0502088102, 2005.
Landolfi, A., Kähler, P., Koeve, W., and Oschlies, A.: Global marine N2 fixation estimates: From observations to models, Front. Microbiol., 9, 1–8, https://doi.org/10.3389/fmicb.2018.02112, 2018.
Lavik, G., Stührmann, T., Brüchert, V., Van Der Plas, A., Mohrholz, V., Lam, P., Mußmann, M., Fuchs, B. M., Amann, R., Lass, U., and Kuypers, M. M. M.: Detoxification of sulphidic African shelf waters by blooming chemolithotrophs, Nature, 457, 581–584, https://doi.org/10.1038/nature07588, 2009.
Lehmann, M. F., Bernasconi, S. M., Barbieri, A., Simona, M., and McKenzie, J. A.: Interannual variation of the isotopic composition of sedimenting organic carbon and nitrogen in Lake Lugano: A long-term sediment trap study, Limnol. Oceanogr., 49, 839–849, https://doi.org/10.4319/lo.2004.49.3.0839, 2004.
Lehmann, M. F., Sigman, D. M., McCorkle, D. C., Granger, J., Hoffmann, S., Cane, G., and Brunelle, B. G.: The distribution of nitrate 15N∕14N in marine sediments and the impact of benthic nitrogen loss on the isotopic composition of oceanic nitrate, Geochim. Cosmochim. Ac., 71, 5384–5404, https://doi.org/10.1016/j.gca.2007.07.025, 2007.
Locarnini, R. A., Mishonov, A. V., Antonov, J. I., Boyer, T. P., Garcia, H. E., Baranova, O. K., Zweng, M. M., Paver, C. R., Reagan, J. R., Johnson, D. R., Hamilton, M., and Seidov, D.: World Ocean Atlas 2013, Vol. 1: Temperature, NOAA Atlas NESDIS 73, Silver Spring, MD, USA, 40 pp., 2013.
Marconi, D., Weigand, M. A., Rafter, P. A., McIlvin, M. R., Forbes, M., Casciotti, K. L., and Sigman, D. M.: Nitrate isotope distributions on the US GEOTRACES North Atlantic cross-basin section: Signals of polar nitrate sources and low latitude nitrogen cycling, Mar. Chem., 177, 143–156, https://doi.org/10.1016/j.marchem.2015.06.007, 2015.
Marconi, D., Kopf, S., Rafter, P. A., and Sigman, D. M.: Aerobic respiration along isopycnals leads to overestimation of the isotope effect of denitrification in the ocean water column, Geochim. Cosmochim. Ac., 197, 417–432, https://doi.org/10.1016/j.gca.2016.10.012, 2017.
Mariotti, A.: Atmospheric nitrogen is a reliable standard for natural 15N abundance measurements, Nature, 303, 685–687, https://doi.org/10.1038/303685a0, 1983.
Mariotti, A., Germon, J. C., Hubert, P., Kaiser, P., Letolle, R., Tardieux, A., and Tardieux, P.: Experimental determination of nitrogen kinetic isotope fractionation: Some principles; illustration for the denitrification and nitrification processes, Plant Soil, 62, 413–430, https://doi.org/10.1007/BF02374138, 1981.
Martin, J. H., Knauer, G. A., Karl, D. M., and Broenkow, W. W.: VERTEX: carbon cycling in the northeast Pacific, Deep-Sea Res., 34, 267–285, https://doi.org/10.1016/0198-0149(87)90086-0, 1987.
Martin, T. S. and Casciotti, K. L.: Nitrogen and oxygen isotopic fractionation during microbial nitrite reduction, Limnol. Oceanogr., 61, 1134–1143, https://doi.org/10.1002/lno.10278, 2016.
Martin, T. S. and Casciotti, K. L.: Paired N and O isotopic analysis of nitrate and nitrite in the Arabian Sea oxygen deficient zone, Deep-Sea Res. Pt. I, 121, 121–131, https://doi.org/10.1016/j.dsr.2017.01.002, 2017.
Martin, T. S., Primeau, F., and Casciotti, K. L.: Model output from N isotope global inverse model, Stanford Digital Repository, https://doi.org/10.25740/VA90-CT15, 2018.
Martin, T. S., Primeau, F., and Casciotti, K. L.: Assessing marine nitrogen cycle rates and process sensitivities with a global 3D inverse model, Global Biogeochem. Cy., in review, 2019.
Möbius, J.: Isotope fractionation during nitrogen remineralization (ammonification): Implications for nitrogen isotope biogeochemistry, Geochim. Cosmochim. Ac., 105, 422–432, https://doi.org/10.1016/j.gca.2012.11.048, 2013.
Monteiro, F. M., Dutkiewicz, S., and Follows, M. J.: Biogeographical controls on the marine nitrogen fixers, Global Biogeochem. Cy., 25, GB2003, https://doi.org/10.1029/2010GB003902, 2011.
Moore, J. K. and Doney, S. C.: Iron availability limits the ocean nitrogen inventory stabilizing feedbacks between marine denitrification and nitrogen fixation, Global Biogeochem. Cy., 21, GB2001, https://doi.org/10.1029/2006GB002762, 2007.
Moore, J. K., Doney, S. C., and Lindsay, K.: Upper ocean ecosystem dynamics and iron cycling in a global three-dimensional model, Global Biogeochem. Cy., 18, GB4028, https://doi.org/10.1029/2004GB002220, 2004.
Nixon, S. W., Ammerman, J. W., Atkinson, L. P., Berousky, V. M., Billen, G., Boicourt, W. C., Boynton, W. R., Church, T. M., Ditoro, D. M., Elmgren, R., Garber, J. H., Giblin, A. E., Jahnke, R. A., Owens, N. J. P., Pilson, M. E. Q., and Seitzinger, S. P.: The fate of nitrogen and phosphorus at the land-sea margin of the North Atlantic Ocean Five major rivers with an average water flow exceeding 3000 m3 s−1 discharge, Biogeochemistry, 35, 141–180, 1996.
Noffke, A., Hensen, C., Sommer, S., Scholz, F., Bohlen, L., Mosch, T., Graco, M., and Wallmann, K.: Benthic iron and phosphorus fluxes across the Peruvian oxygen minimum zone, Limnol. Oceanogr., 57, 851–867, https://doi.org/10.4319/lo.2012.57.3.0851, 2012.
Peng, X., Fuchsman, C. A., Jayakumar, A., Warner, M. J., Devol, A. H., and Ward, B. B.: Revisiting nitrification in the Eastern Tropical South Pacific: A focus on controls, J. Geophys. Res.-Oceans, 121, 1667–1684, https://doi.org/10.1002/2015JC011455, 2016.
Penn, J., Weber, T., and Deutsch, C.: Microbial functional diversity alters the structure and sensitivity of oxygen deficient zones, Geophys. Res. Lett., 43, 9773–9780, https://doi.org/10.1002/2016GL070438, 2016.
Peters, B. D., Babbin, A. R., Lettmann, K. A., Mordy, C. W., Ulloa, O., Ward, B. B., and Casciotti, K. L.: Vertical modeling of the nitrogen cycle in the eastern tropical South Pacific oxygen deficient zone using high-resolution concentration and isotope measurements, Global Biogeochem. Cy., 30, 1661–1681, https://doi.org/10.1002/2016GB005415, 2016.
Peters, B. D., Lam, P. J., and Casciotti, K. L.: Nitrogen and oxygen isotope measurements of nitrate along the US GEOTRACES Eastern Pacific Zonal Transect (GP16) yield insights into nitrate supply, remineralization, and water mass transport, Mar. Chem., 201, 137–150, https://doi.org/10.1016/j.marchem.2017.09.009, 2018a.
Peters, B. D., Horak, R., Devol, A., Fuchsman, C., Forbes, M., Mordy, C. W., and Casciotti, K. L.: Estimating fixed nitrogen loss and associated isotope effects using concentration and isotope measurements of , , and N2 from the Eastern Tropical South Pacific oxygen deficient zone, Deep-Sea Res. Pt. II, https://doi.org/10.1016/j.dsr2.2018.02.011, 2018b.
Rafter, P. A., DiFiore, P. J., and Sigman, D. M.: Coupled nitrate nitrogen and oxygen isotopes and organic matter remineralization in the Southern and Pacific Oceans, J. Geophys. Res.-Oceans, 118, 4781–4794, https://doi.org/10.1002/jgrc.20316, 2013.
Rafter, P. A., Bagnell, A., Marconi, D., and DeVries, T.: Global trends in marine nitrate N isotopes from observations and a neural network-based climatology, Biogeosciences Discuss., https://doi.org/10.5194/bg-2018-525, in review, 2019.
Raimbault, P., Garcia, N., and Cerutti, F.: Distribution of inorganic and organic nutrients in the South Pacific Ocean – evidence for long-term accumulation of organic matter in nitrogen-depleted waters, Biogeosciences, 5, 281–298, https://doi.org/10.5194/bg-5-281-2008, 2008.
Redfield, A. C., Ketchum, B. H., and Richards, F. A.: The Influence of Organisms on the Composition of Sea Water, Sea, 2, 26–77, 1963.
Ryabenko, E., Kock, A., Bange, H. W., Altabet, M. A., and Wallace, D. W. R.: Contrasting biogeochemistry of nitrogen in the Atlantic and Pacific Oxygen Minimum Zones, Biogeosciences, 9, 203–215, https://doi.org/10.5194/bg-9-203-2012, 2012.
Seitzinger, S. P. and Giblin, A. E.: Estimating denitrification in North Atlantic continental shelf sediments, Biogeochemistry, 35, 235–260, https://doi.org/10.1007/BF02179829, 1996.
Shiozaki, T., Bombar, D., Riemann, L., Hashihama, F., Takeda, S., Yamaguchi, T., Ehama, M., Hamasaki, K., and Furuya, K.: Basin scale variability of active diazotrophs and nitrogen fixation in the North Pacific, from the tropics to the subarctic Bering Sea, Global Biogeochem. Cy., 31, 996–1009, https://doi.org/10.1002/2017GB005681, 2017.
Sigman, D. M., DiFiore, P. J., Hain, M. P., Deutsch, C., Wang, Y., Karl, D. M., Knapp, A. N., Lehmann, M. F., and Pantoja, S.: The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen, Deep-Sea Res. Pt. I, 56, 1419–1439, https://doi.org/10.1016/j.dsr.2009.04.007, 2009.
Somes, C. J. and Oschlies, A.: On the influence of “non-Redfield” dissolved organic nutrient dynamics on the spatial distribution of N2 fixation and the size of the marine fixed nitrogen inventory, Global Biogeochem. Cy., 29, 973–993, https://doi.org/10.1002/2014GB005050, 2015.
Somes, C. J., Schmittner, A., Galbraith, E. D., Lehmann, M. F., Altabet, M. A., Montoya, J. P., Letelier, R. M., Mix, A. C., Bourbonnais, A., and Eby, M.: Simulating the global distribution of nitrogen isotopes in the ocean, Global Biogeochem. Cy., 24, GB4019, https://doi.org/10.1029/2009GB003767, 2010.
Strous, M., Fuerst, J. A., Kramer, E. H. M., Logemann, S., Muyzer, G., van de Pas-Schoonen, K. T., Webb, R., Kuenen, J. G., and Jetten, M. S. M.: Missing lithotroph identified as new planctomycete, Nature, 400, 446–449, https://doi.org/10.1038/22749, 1999.
Van Mooy, B. A. S., Keil, R. G., and Devol, A. H.: Impact of suboxia on sinking particulate organic carbon: Enhanced carbon flux and preferential degradation of amino acids via denitrification, Geochim. Cosmochim. Ac., 66, 457–465, https://doi.org/10.1016/S0016-7037(01)00787-6, 2002.
Ward, B. B.: How Nitrogen Is Lost, Science, 341, 352–353, https://doi.org/10.1126/science.1240314, 2013.
Westberry, T., Behrenfeld, M. J., Siegel, D. A., and Boss, E.: Carbon-based primary productivity modeling with vertically resolved photoacclimation, Global Biogeochem. Cy., 22, GB2024, https://doi.org/10.1029/2007GB003078, 2008.
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.
Nitrite is a key intermediate in many nitrogen (N) cycling processes in the ocean, particularly...