Articles | Volume 13, issue 21
https://doi.org/10.5194/bg-13-6049-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-13-6049-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
03 Nov 2016
Research article |
| 03 Nov 2016
Unveiling the Si cycle using isotopes in an iron-fertilized zone of the Southern Ocean: from mixed-layer supply to export
Ivia Closset
CORRESPONDING AUTHOR
Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN
Laboratory, 4 place Jussieu, 75005 Paris, France
Damien Cardinal
Sorbonne Universités (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN
Laboratory, 4 place Jussieu, 75005 Paris, France
Mathieu Rembauville
Sorbonne Universités (UPMC, Univ Paris 06)-CNRS, Laboratoire
d'Océanographie Microbienne (LOMIC), Observatoire Océanologique,
66650 Banyuls/mer, France
François Thil
Laboratoire des Sciences du Climat et de l'Environnement, CNRS 91190
Gif-sur-Yvette, France
Stéphane Blain
Sorbonne Universités (UPMC, Univ Paris 06)-CNRS, Laboratoire
d'Océanographie Microbienne (LOMIC), Observatoire Océanologique,
66650 Banyuls/mer, France
Related authors
A. J. Cavagna, F. Fripiat, M. Elskens, P. Mangion, L. Chirurgien, I. Closset, M. Lasbleiz, L. Florez-Leiva, D. Cardinal, K. Leblanc, C. Fernandez, D. Lefèvre, L. Oriol, S. Blain, B. Quéguiner, and F. Dehairs
Biogeosciences, 12, 6515–6528, https://doi.org/10.5194/bg-12-6515-2015, https://doi.org/10.5194/bg-12-6515-2015, 2015
Short summary
Short summary
Primary production, NO3- and NH4+ uptake, and nitrification rates were measured during the KEOPS 2 cruise (austral spring 2011) in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production which is much higher in the fertilized areas compared to the HNLC site. We report high rates of nitrification in the mixed layer below the euphotic zone. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.
I. Closset, M. Lasbleiz, K. Leblanc, B. Quéguiner, A.-J. Cavagna, M. Elskens, J. Navez, and D. Cardinal
Biogeosciences, 11, 5827–5846, https://doi.org/10.5194/bg-11-5827-2014, https://doi.org/10.5194/bg-11-5827-2014, 2014
Mathieu Rembauville, Stéphane Blain, Clara Manno, Geraint Tarling, Anu Thompson, George Wolff, and Ian Salter
Biogeosciences, 15, 3071–3084, https://doi.org/10.5194/bg-15-3071-2018, https://doi.org/10.5194/bg-15-3071-2018, 2018
Short summary
Short summary
Sinking phytoplankton from the surface ocean provide the principal energy source to deep-ocean ecosystems. Our aim was to understand how different phytoplankton communities impact the chemical nature of this sinking material. We show certain types of phytoplankton can preferentially export energy-rich storage compounds to the seafloor. Any climate-driven effects on phytoplankton community structure could thus impact remote deep-ocean ecosystems thousands of kilometres beneath the surface.
A. J. Cavagna, F. Fripiat, M. Elskens, P. Mangion, L. Chirurgien, I. Closset, M. Lasbleiz, L. Florez-Leiva, D. Cardinal, K. Leblanc, C. Fernandez, D. Lefèvre, L. Oriol, S. Blain, B. Quéguiner, and F. Dehairs
Biogeosciences, 12, 6515–6528, https://doi.org/10.5194/bg-12-6515-2015, https://doi.org/10.5194/bg-12-6515-2015, 2015
Short summary
Short summary
Primary production, NO3- and NH4+ uptake, and nitrification rates were measured during the KEOPS 2 cruise (austral spring 2011) in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production which is much higher in the fertilized areas compared to the HNLC site. We report high rates of nitrification in the mixed layer below the euphotic zone. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.
F. d'Ovidio, A. Della Penna, T. W. Trull, F. Nencioli, M.-I. Pujol, M.-H. Rio, Y.-H. Park, C. Cotté, M. Zhou, and S. Blain
Biogeosciences, 12, 5567–5581, https://doi.org/10.5194/bg-12-5567-2015, https://doi.org/10.5194/bg-12-5567-2015, 2015
Short summary
Short summary
Field campaigns are instrumental in providing ground truth for understanding and modeling global ocean biogeochemical budgets. A survey however can only inspect a fraction of the global oceans, typically a region hundreds of kilometers wide for a temporal window of the order of (at most) several weeks. In this spatiotemporal domain, mesoscale variability can mask climatological contrasts. Here we propose the use of multisatellite-based Lagrangian diagnostics to solve this issue.
A. R. Bowie, P. van der Merwe, F. Quéroué, T. Trull, M. Fourquez, F. Planchon, G. Sarthou, F. Chever, A. T. Townsend, I. Obernosterer, J.-B. Sallée, and S. Blain
Biogeosciences, 12, 4421–4445, https://doi.org/10.5194/bg-12-4421-2015, https://doi.org/10.5194/bg-12-4421-2015, 2015
Short summary
Short summary
Iron biogeochemical budgets during the natural ocean fertilisation experiment KEOPS-2 showed that complex circulation and transport pathways were responsible for differences in the mode and strength of iron supply, with vertical supply dominant on the plateau and lateral supply dominant in the plume. The exchange of iron between dissolved, biogenic and lithogenic pools was highly dynamic, resulting in a decoupling of iron supply and carbon export and controlling the efficiency of fertilization.
F. Quéroué, G. Sarthou, H. F. Planquette, E. Bucciarelli, F. Chever, P. van der Merwe, D. Lannuzel, A. T. Townsend, M. Cheize, S. Blain, F. d'Ovidio, and A. R. Bowie
Biogeosciences, 12, 3869–3883, https://doi.org/10.5194/bg-12-3869-2015, https://doi.org/10.5194/bg-12-3869-2015, 2015
Short summary
Short summary
Dissolved Fe (dFe) concentrations were measured in the vicinity of the Kerguelen Islands. Direct island runoff, glacial melting, and resuspended sediments were identified as important inputs of dFe that could potentially fertilise the northern part of the plateau. Overall, heterogeneous sources of Fe over and off the plateau, in addition to strong variability in Fe supply by vertical or horizontal transport, may explain the high variability in dFe concentrations observed during this study.
M. Rembauville, I. Salter, N. Leblond, A. Gueneugues, and S. Blain
Biogeosciences, 12, 3153–3170, https://doi.org/10.5194/bg-12-3153-2015, https://doi.org/10.5194/bg-12-3153-2015, 2015
M. Rembauville, S. Blain, L. Armand, B. Quéguiner, and I. Salter
Biogeosciences, 12, 3171–3195, https://doi.org/10.5194/bg-12-3171-2015, https://doi.org/10.5194/bg-12-3171-2015, 2015
I. Obernosterer, M. Fourquez, and S. Blain
Biogeosciences, 12, 1983–1992, https://doi.org/10.5194/bg-12-1983-2015, https://doi.org/10.5194/bg-12-1983-2015, 2015
M. Fourquez, I. Obernosterer, D. M. Davies, T. W. Trull, and S. Blain
Biogeosciences, 12, 1893–1906, https://doi.org/10.5194/bg-12-1893-2015, https://doi.org/10.5194/bg-12-1893-2015, 2015
Short summary
Short summary
In this manuscript, we present the results of iron uptake measured in the naturally iron-fertilized area during the Kerguelen Ocean and Plateau compared Study 2 cruise (KEOPS2). Iron uptake by bulk community and several size fractions (microplankton, pico-nanoplankton and bacteria) are presented, compared and discussed in the present paper. This work also presents first investigations on the potential competition between bacteria and phytoplankton for access to iron.
S. H. M. Jacquet, F. Dehairs, D. Lefèvre, A. J. Cavagna, F. Planchon, U. Christaki, L. Monin, L. André, I. Closset, and D. Cardinal
Biogeosciences, 12, 1713–1731, https://doi.org/10.5194/bg-12-1713-2015, https://doi.org/10.5194/bg-12-1713-2015, 2015
V. Sanial, P. van Beek, B. Lansard, M. Souhaut, E. Kestenare, F. d'Ovidio, M. Zhou, and S. Blain
Biogeosciences, 12, 1415–1430, https://doi.org/10.5194/bg-12-1415-2015, https://doi.org/10.5194/bg-12-1415-2015, 2015
Short summary
Short summary
We investigated the origin and mechanisms of the natural iron fertilization that sustains a phytoplankton bloom downstream of the Kerguelen Islands. We used radium isotopes to trace the fate of shelf waters that may transport iron and other micronutrients towards offshore waters. We show that shelf waters are rapidly transferred offshore and may be transported across the polar front (PF). The PF may thus not be a strong physical barrier for chemical elements released by the shelf sediments.
T. W. Trull, D. M. Davies, F. Dehairs, A.-J. Cavagna, M. Lasbleiz, E. C. Laurenceau-Cornec, F. d'Ovidio, F. Planchon, K. Leblanc, B. Quéguiner, and S. Blain
Biogeosciences, 12, 1029–1056, https://doi.org/10.5194/bg-12-1029-2015, https://doi.org/10.5194/bg-12-1029-2015, 2015
Short summary
Short summary
The KEOPS2 oceanographic study surveyed more than 30 sites downstream from the Kerguelen Islands in the Southern Ocean to examine the degree of variation in phytoplankton community responses to natural iron inputs. Our observations of community structure based on the chemical compositions of six microbial size fractions suggest that early spring trophodynamic and export responses differed between regions with persistently low levels versus punctually high levels of iron fertilisation.
E. C. Laurenceau-Cornec, T. W. Trull, D. M. Davies, S. G. Bray, J. Doran, F. Planchon, F. Carlotti, M.-P. Jouandet, A.-J. Cavagna, A. M. Waite, and S. Blain
Biogeosciences, 12, 1007–1027, https://doi.org/10.5194/bg-12-1007-2015, https://doi.org/10.5194/bg-12-1007-2015, 2015
P. van der Merwe, A. R. Bowie, F. Quéroué, L. Armand, S. Blain, F. Chever, D. Davies, F. Dehairs, F. Planchon, G. Sarthou, A. T. Townsend, and T. W. Trull
Biogeosciences, 12, 739–755, https://doi.org/10.5194/bg-12-739-2015, https://doi.org/10.5194/bg-12-739-2015, 2015
Short summary
Short summary
Trace metal analysis of suspended and settling particles and underlying sediment was undertaken to elucidate the source to sink progression of the particulate trace metal pool near Kerguelen Island (Southern Ocean). Findings indicate that the Kerguelen Plateau is a source of trace metals via resuspended shelf sediments, especially below the mixed layer. However, glacial/fluvial runoff into shallow coastal waters is an important mode of fertilisation to areas downstream of Kerguelen Island.
S. Blain, J. Capparos, A. Guéneuguès, I. Obernosterer, and L. Oriol
Biogeosciences, 12, 623–635, https://doi.org/10.5194/bg-12-623-2015, https://doi.org/10.5194/bg-12-623-2015, 2015
U. Christaki, D. Lefèvre, C. Georges, J. Colombet, P. Catala, C. Courties, T. Sime-Ngando, S. Blain, and I. Obernosterer
Biogeosciences, 11, 6739–6753, https://doi.org/10.5194/bg-11-6739-2014, https://doi.org/10.5194/bg-11-6739-2014, 2014
Short summary
Short summary
The concurrent investigation of several parameters has provided insight into two key roles of heterotrophic bacteria, and the microbial food web functioning, at the onset and late phase of the spring phytoplankton bloom induced by natural iron fertilization in the Southern Ocean.
M. Lasbleiz, K. Leblanc, S. Blain, J. Ras, V. Cornet-Barthaux, S. Hélias Nunige, and B. Quéguiner
Biogeosciences, 11, 5931–5955, https://doi.org/10.5194/bg-11-5931-2014, https://doi.org/10.5194/bg-11-5931-2014, 2014
I. Closset, M. Lasbleiz, K. Leblanc, B. Quéguiner, A.-J. Cavagna, M. Elskens, J. Navez, and D. Cardinal
Biogeosciences, 11, 5827–5846, https://doi.org/10.5194/bg-11-5827-2014, https://doi.org/10.5194/bg-11-5827-2014, 2014
M.-P. Jouandet, G. A. Jackson, F. Carlotti, M. Picheral, L. Stemmann, and S. Blain
Biogeosciences, 11, 4393–4406, https://doi.org/10.5194/bg-11-4393-2014, https://doi.org/10.5194/bg-11-4393-2014, 2014
M. Zhou, Y. Zhu, F. d'Ovidio, Y.-H. Park, I. Durand, E. Kestenare, V. Sanial, P. Van-Beek, B. Queguiner, F. Carlotti, and S. Blain
Biogeosciences Discuss., https://doi.org/10.5194/bgd-11-6845-2014, https://doi.org/10.5194/bgd-11-6845-2014, 2014
Revised manuscript has not been submitted
C. Guinet, X. Xing, E. Walker, P. Monestiez, S. Marchand, B. Picard, T. Jaud, M. Authier, C. Cotté, A. C. Dragon, E. Diamond, D. Antoine, P. Lovell, S. Blain, F. D'Ortenzio, and H. Claustre
Earth Syst. Sci. Data, 5, 15–29, https://doi.org/10.5194/essd-5-15-2013, https://doi.org/10.5194/essd-5-15-2013, 2013
Related subject area
Biogeochemistry: Open Ocean
Anthropogenic carbon storage and its decadal changes in the Atlantic between 1990–2020
Ocean alkalinity enhancement impacts: regrowth of marine microalgae in alkaline mineral concentrations simulating the initial concentrations after ship-based dispersions
Climatic controls on metabolic constraints in the ocean
Effects of grain size and seawater salinity on magnesium hydroxide dissolution and secondary calcium carbonate precipitation kinetics: implications for ocean alkalinity enhancement
Short-term response of Emiliania huxleyi growth and morphology to abrupt salinity stress
Assessing the impact of CO2-equilibrated ocean alkalinity enhancement on microbial metabolic rates in an oligotrophic system
Phosphomonoesterase and phosphodiesterase activities in the eastern Mediterranean in two contrasting seasonal situations
Hydrological cycle amplification imposes spatial pattern on climate change response of ocean pH and carbonate chemistry
Net primary production annual maxima in the North Atlantic projected to shift in the 21st century
Testing the influence of light on nitrite cycling in the eastern tropical North Pacific
Loss of nitrogen via anaerobic ammonium oxidation (anammox) in the California Current system during the late Quaternary
Drivers of decadal trends of the ocean carbon sink in the past, present, and future in Earth system models
Technical note: Assessment of float pH data quality control methods – a case study in the subpolar northwest Atlantic Ocean
Linking northeastern North Pacific oxygen changes to upstream surface outcrop variations
Evaluation of CMIP6 Models Performance in Simulating Historical Biogeochemistry across Southern South China Sea
Underestimation of multi-decadal global O2 loss due to an optimal interpolation method
Reviews and syntheses: expanding the global coverage of gross primary production and net community production measurements using Biogeochemical-Argo floats
Assessing the tropical Atlantic biogeochemical processes in the Norwegian Earth System Model
Characteristics of surface physical and biogeochemical parameters within mesoscale eddies in the Southern Ocean
Seasonal dynamics and annual budget of dissolved inorganic carbon in the northwestern Mediterranean deep-convection region
The fingerprint of climate variability on the surface ocean cycling of iron and its isotopes
Reconstructing the ocean's mesopelagic zone carbon budget: sensitivity and estimation of parameters associated with prokaryotic remineralization
Evolution of oxygen and stratification in the North Pacific Ocean in CMIP6 Earth System Models
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean: a stable isotope approach
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump
Importance of multiple sources of iron for the upper-ocean biogeochemistry over the northern Indian Ocean
Exploring the role of different data types and timescales in the quality of marine biogeochemical model calibration
All about nitrite: exploring nitrite sources and sinks in the eastern tropical North Pacific oxygen minimum zone
Fossil coccolith morphological attributes as a new proxy for deep ocean carbonate chemistry
Reconstructing ocean carbon storage with CMIP6 Earth system models and synthetic Argo observations
Using machine learning and Biogeochemical-Argo (BGC-Argo) floats to assess biogeochemical models and optimize observing system design
The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle
Model estimates of metazoans' contributions to the biological carbon pump
Tracing differences in iron supply to the Mid-Atlantic Ridge valley between hydrothermal vent sites: implications for the addition of iron to the deep ocean
Nitrite cycling in the primary nitrite maxima of the eastern tropical North Pacific
Hotspots and drivers of compound marine heatwaves and low net primary production extremes
Ecosystem impacts of marine heat waves in the northeast Pacific
Tracing the role of Arctic shelf processes in Si and N cycling and export through the Fram Strait: insights from combined silicon and nitrate isotopes
Controls on the relative abundances and rates of nitrifying microorganisms in the ocean
The response of diazotrophs to nutrient amendment in the South China Sea and western North Pacific
Influence of GEOTRACES data distribution and misfit function choice on objective parameter retrieval in a marine zinc cycle model
Physiological flexibility of phytoplankton impacts modelled chlorophyll and primary production across the North Pacific Ocean
Observation-constrained estimates of the global ocean carbon sink from Earth system models
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise)
Controlling factors on the global distribution of a representative marine non-cyanobacterial diazotroph phylotype (Gamma A)
Summer trends and drivers of sea surface fCO2 and pH changes observed in the southern Indian Ocean over the last two decades (1998–2019)
Global nutrient cycling by commercially targeted marine fish
Major processes of the dissolved cobalt cycle in the North and equatorial Pacific Ocean
The impact of the South-East Madagascar Bloom on the oceanic CO2 sink
Reiner Steinfeldt, Monika Rhein, and Dagmar Kieke
Biogeosciences, 21, 3839–3867, https://doi.org/10.5194/bg-21-3839-2024, https://doi.org/10.5194/bg-21-3839-2024, 2024
Short summary
Short summary
We calculate the amount of anthropogenic carbon (Cant) in the Atlantic for the years 1990, 2000, 2010 and 2020. Cant is the carbon that is taken up by the ocean as a result of humanmade CO2 emissions. To determine the amount of Cant, we apply a technique that is based on the observations of other humanmade gases (e.g., chlorofluorocarbons). Regionally, changes in ocean ventilation have an impact on the storage of Cant. Overall, the increase in Cant is driven by the rising CO2 in the atmosphere.
Stephanie Delacroix, Tor Jensen Nystuen, August E. Dessen Tobiesen, Andrew L. King, and Erik Höglund
Biogeosciences, 21, 3677–3690, https://doi.org/10.5194/bg-21-3677-2024, https://doi.org/10.5194/bg-21-3677-2024, 2024
Short summary
Short summary
The addition of alkaline minerals into the ocean might reduce excessive anthropogenic CO2 emissions. Magnesium hydroxide can be added in large amounts because of its low seawater solubility without reaching harmful pH levels. The toxicity effect results of magnesium hydroxide, by simulating the expected concentrations from a ship's dispersion scenario, demonstrated low impacts on both sensitive and local assemblages of marine microalgae when compared to calcium hydroxide.
Precious Mongwe, Matthew Long, Takamitsu Ito, Curtis Deutsch, and Yeray Santana-Falcón
Biogeosciences, 21, 3477–3490, https://doi.org/10.5194/bg-21-3477-2024, https://doi.org/10.5194/bg-21-3477-2024, 2024
Short summary
Short summary
We use a collection of measurements that capture the physiological sensitivity of organisms to temperature and oxygen and a CESM1 large ensemble to investigate how natural climate variations and climate warming will impact the ability of marine heterotrophic marine organisms to support habitats in the future. We find that warming and dissolved oxygen loss over the next several decades will reduce the volume of ocean habitats and will increase organisms' vulnerability to extremes.
Charly A. Moras, Tyler Cyronak, Lennart T. Bach, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 21, 3463–3475, https://doi.org/10.5194/bg-21-3463-2024, https://doi.org/10.5194/bg-21-3463-2024, 2024
Short summary
Short summary
We investigate the effects of mineral grain size and seawater salinity on magnesium hydroxide dissolution and calcium carbonate precipitation kinetics for ocean alkalinity enhancement. Salinity did not affect the dissolution, but calcium carbonate formed earlier at lower salinities due to the lower magnesium and dissolved organic carbon concentrations. Smaller grain sizes dissolved faster but calcium carbonate precipitated earlier, suggesting that medium grain sizes are optimal for kinetics.
Rosie M. Sheward, Christina Gebühr, Jörg Bollmann, and Jens O. Herrle
Biogeosciences, 21, 3121–3141, https://doi.org/10.5194/bg-21-3121-2024, https://doi.org/10.5194/bg-21-3121-2024, 2024
Short summary
Short summary
How quickly do marine microorganisms respond to salinity stress? Our experiments with the calcifying marine plankton Emiliania huxleyi show that growth and cell morphology responded to salinity stress within as little as 24–48 hours, demonstrating that morphology and calcification are sensitive to salinity over a range of timescales. Our results have implications for understanding the short-term role of E. huxleyi in biogeochemical cycles and in size-based paleoproxies for salinity.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, Joaquín Ortiz, Stephen D. Archer, Andrea Ludwig, and Ulf Riebesell
Biogeosciences, 21, 2859–2876, https://doi.org/10.5194/bg-21-2859-2024, https://doi.org/10.5194/bg-21-2859-2024, 2024
Short summary
Short summary
Our planet is facing a climate crisis. Scientists are working on innovative solutions that will aid in capturing the hard to abate emissions before it is too late. Exciting research reveals that ocean alkalinity enhancement, a key climate change mitigation strategy, does not harm phytoplankton, the cornerstone of marine ecosystems. Through meticulous study, we may have uncovered a positive relationship: up to a specific limit, enhancing ocean alkalinity boosts photosynthesis by certain species.
France Van Wambeke, Pascal Conan, Mireille Pujo-Pay, Vincent Taillandier, Olivier Crispi, Alexandra Pavlidou, Sandra Nunige, Morgane Didry, Christophe Salmeron, and Elvira Pulido-Villena
Biogeosciences, 21, 2621–2640, https://doi.org/10.5194/bg-21-2621-2024, https://doi.org/10.5194/bg-21-2621-2024, 2024
Short summary
Short summary
Phosphomonoesterase (PME) and phosphodiesterase (PDE) activities over the epipelagic zone are described in the eastern Mediterranean Sea in winter and autumn. The types of concentration kinetics obtained for PDE (saturation at 50 µM, high Km, high turnover times) compared to those of PME (saturation at 1 µM, low Km, low turnover times) are discussed in regard to the possible inequal distribution of PDE and PME in the size continuum of organic material and accessibility to phosphodiesters.
Allison Hogikyan and Laure Resplandy
EGUsphere, https://doi.org/10.5194/egusphere-2024-1189, https://doi.org/10.5194/egusphere-2024-1189, 2024
Short summary
Short summary
Rising atmospheric CO2 influences ocean carbon chemistry leading to ocean acidification. Global warming introduces spatial patterns in the intensity of ocean acidification. We show that the most prominent spatial patterns are controlled by warming-driven changes in rainfall and evaporation, and not by the direct effect of warming on carbon chemistry and pH. This rainfall/evaporation effect opposes acidification in saltier parts of the ocean and enhances acidification in fresher regions.
Jenny Hieronymus, Magnus Hieronymus, Matthias Gröger, Jörg Schwinger, Raffaele Bernadello, Etienne Tourigny, Valentina Sicardi, Itzel Ruvalcaba Baroni, and Klaus Wyser
Biogeosciences, 21, 2189–2206, https://doi.org/10.5194/bg-21-2189-2024, https://doi.org/10.5194/bg-21-2189-2024, 2024
Short summary
Short summary
The timing of the net primary production annual maxima in the North Atlantic in the period 1750–2100 is investigated using two Earth system models and the high-emissions scenario SSP5-8.5. It is found that, for most of the region, the annual maxima occur progressively earlier, with the most change occurring after the year 2000. Shifts in the seasonality of the primary production may impact the entire ecosystem, which highlights the need for long-term monitoring campaigns in this area.
Nicole M. Travis, Colette L. Kelly, and Karen L. Casciotti
Biogeosciences, 21, 1985–2004, https://doi.org/10.5194/bg-21-1985-2024, https://doi.org/10.5194/bg-21-1985-2024, 2024
Short summary
Short summary
We conducted experimental manipulations of light level on microbial communities from the primary nitrite maximum. Overall, while individual microbial processes have different directions and magnitudes in their response to increasing light, the net community response is a decline in nitrite production with increasing light. We conclude that while increased light may decrease net nitrite production, high-light conditions alone do not exclude nitrification from occurring in the surface ocean.
Zoë Rebecca van Kemenade, Zeynep Erdem, Ellen Christine Hopmans, Jaap Smede Sinninghe Damsté, and Darci Rush
Biogeosciences, 21, 1517–1532, https://doi.org/10.5194/bg-21-1517-2024, https://doi.org/10.5194/bg-21-1517-2024, 2024
Short summary
Short summary
The California Current system (CCS) hosts the eastern subtropical North Pacific oxygen minimum zone (ESTNP OMZ). This study shows anaerobic ammonium oxidizing (anammox) bacteria cause a loss of bioavailable nitrogen (N) in the ESTNP OMZ throughout the late Quaternary. Anammox occurred during both glacial and interglacial periods and was driven by the supply of organic matter and changes in ocean currents. These findings may have important consequences for biogeochemical models of the CCS.
Jens Terhaar
EGUsphere, https://doi.org/10.5194/egusphere-2024-773, https://doi.org/10.5194/egusphere-2024-773, 2024
Short summary
Short summary
Despite the ocean’s importance for the carbon cycle and hence the climate, observing the ocean carbon sink remains challenging. Here, I use an ensemble of 12 Models to understand drivers of decadal trends of the past, present and future ocean carbon sink. I show that 80 % of decadal trends in the multi-model mean ocean carbon sink can be explained by changes in decadal trends of atmospheric CO2. The remaining 20 % are due to internal climate variability and ocean heat uptake.
Cathy Wimart-Rousseau, Tobias Steinhoff, Birgit Klein, Henry Bittig, and Arne Körtzinger
Biogeosciences, 21, 1191–1211, https://doi.org/10.5194/bg-21-1191-2024, https://doi.org/10.5194/bg-21-1191-2024, 2024
Short summary
Short summary
The marine CO2 system can be measured independently and continuously by BGC-Argo floats since numerous pH sensors have been developed to suit these autonomous measurements platforms. By applying the Argo correction routines to float pH data acquired in the subpolar North Atlantic Ocean, we report the uncertainty and lack of objective criteria associated with the choice of the reference method as well the reference depth for the pH correction.
Sabine Mecking and Kyla Drushka
Biogeosciences, 21, 1117–1133, https://doi.org/10.5194/bg-21-1117-2024, https://doi.org/10.5194/bg-21-1117-2024, 2024
Short summary
Short summary
This study investigates whether northeastern North Pacific oxygen changes may be caused by surface density changes in the northwest as water moves along density horizons from the surface into the subsurface ocean. A correlation is found with a lag that about matches the travel time of water from the northwest to the northeast. Salinity is the main driver causing decadal changes in surface density, whereas salinity and temperature contribute about equally to long-term declining density trends.
Winfred Marshal, Jing Xiang Chung, and Mohd Fadzil Bin Mohd Akhir
EGUsphere, https://doi.org/10.5194/egusphere-2024-72, https://doi.org/10.5194/egusphere-2024-72, 2024
Short summary
Short summary
This study stands out for thoroughly examining CMIP6 ESMs ability to simulate biogeochemical variables in the southern South China Sea, an economically important region. It assesses variables like chlorophyll, phytoplankton, nitrate and oxygen on annual and seasonal scales. While global assessments exist, this study addresses a gap by objectively ranking 13 CMIP6 ocean biogeochemistry models' performance at a regional level, focusing on replicating specific observed biogeochemical variables.
Takamitsu Ito, Hernan E. Garcia, Zhankun Wang, Shoshiro Minobe, Matthew C. Long, Just Cebrian, James Reagan, Tim Boyer, Christopher Paver, Courtney Bouchard, Yohei Takano, Seth Bushinsky, Ahron Cervania, and Curtis A. Deutsch
Biogeosciences, 21, 747–759, https://doi.org/10.5194/bg-21-747-2024, https://doi.org/10.5194/bg-21-747-2024, 2024
Short summary
Short summary
This study aims to estimate how much oceanic oxygen has been lost and its uncertainties. One major source of uncertainty comes from the statistical gap-filling methods. Outputs from Earth system models are used to generate synthetic observations where oxygen data are extracted from the model output at the location and time of historical oceanographic cruises. Reconstructed oxygen trend is approximately two-thirds of the true trend.
Robert W. Izett, Katja Fennel, Adam C. Stoer, and David P. Nicholson
Biogeosciences, 21, 13–47, https://doi.org/10.5194/bg-21-13-2024, https://doi.org/10.5194/bg-21-13-2024, 2024
Short summary
Short summary
This paper provides an overview of the capacity to expand the global coverage of marine primary production estimates using autonomous ocean-going instruments, called Biogeochemical-Argo floats. We review existing approaches to quantifying primary production using floats, provide examples of the current implementation of the methods, and offer insights into how they can be better exploited. This paper is timely, given the ongoing expansion of the Biogeochemical-Argo array.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
EGUsphere, https://doi.org/10.5194/egusphere-2023-2947, https://doi.org/10.5194/egusphere-2023-2947, 2023
Short summary
Short summary
We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to represent the primary production and sea-air CO2 flux in terms of climatology, seasonal cycle, and responses to climate variability.
Qian Liu, Yingjie Liu, and Xiaofeng Li
Biogeosciences, 20, 4857–4874, https://doi.org/10.5194/bg-20-4857-2023, https://doi.org/10.5194/bg-20-4857-2023, 2023
Short summary
Short summary
In the Southern Ocean, abundant eddies behave opposite to our expectations. That is, anticyclonic (cyclonic) eddies are cold (warm). By investigating the variations of physical and biochemical parameters in eddies, we find that abnormal eddies have unique and significant effects on modulating the parameters. This study fills a gap in understanding the effects of abnormal eddies on physical and biochemical parameters in the Southern Ocean.
Caroline Ulses, Claude Estournel, Patrick Marsaleix, Karline Soetaert, Marine Fourrier, Laurent Coppola, Dominique Lefèvre, Franck Touratier, Catherine Goyet, Véronique Guglielmi, Fayçal Kessouri, Pierre Testor, and Xavier Durrieu de Madron
Biogeosciences, 20, 4683–4710, https://doi.org/10.5194/bg-20-4683-2023, https://doi.org/10.5194/bg-20-4683-2023, 2023
Short summary
Short summary
Deep convection plays a key role in the circulation, thermodynamics, and biogeochemical cycles in the Mediterranean Sea, considered to be a hotspot of biodiversity and climate change. In this study, we investigate the seasonal and annual budget of dissolved inorganic carbon in the deep-convection area of the northwestern Mediterranean Sea.
Daniela König and Alessandro Tagliabue
Biogeosciences, 20, 4197–4212, https://doi.org/10.5194/bg-20-4197-2023, https://doi.org/10.5194/bg-20-4197-2023, 2023
Short summary
Short summary
Using model simulations, we show that natural and anthropogenic changes in the global climate leave a distinct fingerprint in the isotopic signatures of iron in the surface ocean. We find that these climate effects on iron isotopes are often caused by the redistribution of iron from different external sources to the ocean, due to changes in ocean currents, and by changes in algal growth, which take up iron. Thus, isotopes may help detect climate-induced changes in iron supply and algal uptake.
Chloé Baumas, Robin Fuchs, Marc Garel, Jean-Christophe Poggiale, Laurent Memery, Frédéric A. C. Le Moigne, and Christian Tamburini
Biogeosciences, 20, 4165–4182, https://doi.org/10.5194/bg-20-4165-2023, https://doi.org/10.5194/bg-20-4165-2023, 2023
Short summary
Short summary
Through the sink of particles in the ocean, carbon (C) is exported and sequestered when reaching 1000 m. Attempts to quantify C exported vs. C consumed by heterotrophs have increased. Yet most of the conducted estimations have led to C demands several times higher than C export. The choice of parameters greatly impacts the results. As theses parameters are overlooked, non-accurate values are often used. In this study we show that C budgets can be well balanced when using appropriate values.
Lyuba Novi, Annalisa Bracco, Takamitsu Ito, and Yohei Takano
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-129, https://doi.org/10.5194/bg-2023-129, 2023
Revised manuscript accepted for BG
Short summary
Short summary
We explored the relationship between oxygen and stratification in the North Pacific Ocean, using a combination of data mining and machine learning. We used isopycnic potential vorticity (IPV) as an indicator to quantify ocean ventilation and we analyzed its predictability, a strong O2-IPV connection and predictability for IPV in the tropical Pacific. This open new routes to monitor ocean O2 through few observational sites co-located with more abundant IPV measurements in the tropical Pacific.
Anna Belcher, Sian F. Henley, Katharine Hendry, Marianne Wootton, Lisa Friberg, Ursula Dallman, Tong Wang, Christopher Coath, and Clara Manno
Biogeosciences, 20, 3573–3591, https://doi.org/10.5194/bg-20-3573-2023, https://doi.org/10.5194/bg-20-3573-2023, 2023
Short summary
Short summary
The oceans play a crucial role in the uptake of atmospheric carbon dioxide, particularly the Southern Ocean. The biological pumping of carbon from the surface to the deep ocean is key to this. Using sediment trap samples from the Scotia Sea, we examine biogeochemical fluxes of carbon, nitrogen, and biogenic silica and their stable isotope compositions. We find phytoplankton community structure and physically mediated processes are important controls on particulate fluxes to the deep ocean.
Asmita Singh, Susanne Fietz, Sandy J. Thomalla, Nicolas Sanchez, Murat V. Ardelan, Sébastien Moreau, Hanna M. Kauko, Agneta Fransson, Melissa Chierici, Saumik Samanta, Thato N. Mtshali, Alakendra N. Roychoudhury, and Thomas J. Ryan-Keogh
Biogeosciences, 20, 3073–3091, https://doi.org/10.5194/bg-20-3073-2023, https://doi.org/10.5194/bg-20-3073-2023, 2023
Short summary
Short summary
Despite the scarcity of iron in the Southern Ocean, seasonal blooms occur due to changes in nutrient and light availability. Surprisingly, during an autumn bloom in the Antarctic sea-ice zone, the results from incubation experiments showed no significant photophysiological response of phytoplankton to iron addition. This suggests that ambient iron concentrations were sufficient, challenging the notion of iron deficiency in the Southern Ocean through extended iron-replete post-bloom conditions.
Benoît Pasquier, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau
Biogeosciences, 20, 2985–3009, https://doi.org/10.5194/bg-20-2985-2023, https://doi.org/10.5194/bg-20-2985-2023, 2023
Short summary
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.
Priyanka Banerjee
Biogeosciences, 20, 2613–2643, https://doi.org/10.5194/bg-20-2613-2023, https://doi.org/10.5194/bg-20-2613-2023, 2023
Short summary
Short summary
This study shows that atmospheric deposition is the most important source of iron to the upper northern Indian Ocean for phytoplankton growth. This is followed by iron from continental-shelf sediment. Phytoplankton increase following iron addition is possible only with high background levels of nitrate. Vertical mixing is the most important physical process supplying iron to the upper ocean in this region throughout the year. The importance of ocean currents in supplying iron varies seasonally.
Iris Kriest, Julia Getzlaff, Angela Landolfi, Volkmar Sauerland, Markus Schartau, and Andreas Oschlies
Biogeosciences, 20, 2645–2669, https://doi.org/10.5194/bg-20-2645-2023, https://doi.org/10.5194/bg-20-2645-2023, 2023
Short summary
Short summary
Global biogeochemical ocean models are often subjectively assessed and tuned against observations. We applied different strategies to calibrate a global model against observations. Although the calibrated models show similar tracer distributions at the surface, they differ in global biogeochemical fluxes, especially in global particle flux. Simulated global volume of oxygen minimum zones varies strongly with calibration strategy and over time, rendering its temporal extrapolation difficult.
John C. Tracey, Andrew R. Babbin, Elizabeth Wallace, Xin Sun, Katherine L. DuRussel, Claudia Frey, Donald E. Martocello III, Tyler Tamasi, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 20, 2499–2523, https://doi.org/10.5194/bg-20-2499-2023, https://doi.org/10.5194/bg-20-2499-2023, 2023
Short summary
Short summary
Nitrogen (N) is essential for life; thus, its availability plays a key role in determining marine productivity. Using incubations of seawater spiked with a rare form of N measurable on a mass spectrometer, we quantified microbial pathways that determine marine N availability. The results show that pathways that recycle N have higher rates than those that result in its loss from biomass and present new evidence for anaerobic nitrite oxidation, a process long thought to be strictly aerobic.
Amanda Gerotto, Hongrui Zhang, Renata Hanae Nagai, Heather M. Stoll, Rubens César Lopes Figueira, Chuanlian Liu, and Iván Hernández-Almeida
Biogeosciences, 20, 1725–1739, https://doi.org/10.5194/bg-20-1725-2023, https://doi.org/10.5194/bg-20-1725-2023, 2023
Short summary
Short summary
Based on the analysis of the response of coccolithophores’ morphological attributes in a laboratory dissolution experiment and surface sediment samples from the South China Sea, we proposed that the thickness shape (ks) factor of fossil coccoliths together with the normalized ks variation, which is the ratio of the standard deviation of ks (σ) over the mean ks (σ/ks), is a robust and novel proxy to reconstruct past changes in deep ocean carbon chemistry.
Katherine E. Turner, Doug M. Smith, Anna Katavouta, and Richard G. Williams
Biogeosciences, 20, 1671–1690, https://doi.org/10.5194/bg-20-1671-2023, https://doi.org/10.5194/bg-20-1671-2023, 2023
Short summary
Short summary
We present a new method for reconstructing ocean carbon using climate models and temperature and salinity observations. To test this method, we reconstruct modelled carbon using synthetic observations consistent with current sampling programmes. Sensitivity tests show skill in reconstructing carbon trends and variability within the upper 2000 m. Our results indicate that this method can be used for a new global estimate for ocean carbon content.
Alexandre Mignot, Hervé Claustre, Gianpiero Cossarini, Fabrizio D'Ortenzio, Elodie Gutknecht, Julien Lamouroux, Paolo Lazzari, Coralie Perruche, Stefano Salon, Raphaëlle Sauzède, Vincent Taillandier, and Anna Teruzzi
Biogeosciences, 20, 1405–1422, https://doi.org/10.5194/bg-20-1405-2023, https://doi.org/10.5194/bg-20-1405-2023, 2023
Short summary
Short summary
Numerical models of ocean biogeochemistry are becoming a major tool to detect and predict the impact of climate change on marine resources and monitor ocean health. Here, we demonstrate the use of the global array of BGC-Argo floats for the assessment of biogeochemical models. We first detail the handling of the BGC-Argo data set for model assessment purposes. We then present 23 assessment metrics to quantify the consistency of BGC model simulations with respect to BGC-Argo data.
Alban Planchat, Lester Kwiatkowski, Laurent Bopp, Olivier Torres, James R. Christian, Momme Butenschön, Tomas Lovato, Roland Séférian, Matthew A. Chamberlain, Olivier Aumont, Michio Watanabe, Akitomo Yamamoto, Andrew Yool, Tatiana Ilyina, Hiroyuki Tsujino, Kristen M. Krumhardt, Jörg Schwinger, Jerry Tjiputra, John P. Dunne, and Charles Stock
Biogeosciences, 20, 1195–1257, https://doi.org/10.5194/bg-20-1195-2023, https://doi.org/10.5194/bg-20-1195-2023, 2023
Short summary
Short summary
Ocean alkalinity is critical to the uptake of atmospheric carbon and acidification in surface waters. We review the representation of alkalinity and the associated calcium carbonate cycle in Earth system models. While many parameterizations remain present in the latest generation of models, there is a general improvement in the simulated alkalinity distribution. This improvement is related to an increase in the export of biotic calcium carbonate, which closer resembles observations.
Jérôme Pinti, Tim DeVries, Tommy Norin, Camila Serra-Pompei, Roland Proud, David A. Siegel, Thomas Kiørboe, Colleen M. Petrik, Ken H. Andersen, Andrew S. Brierley, and André W. Visser
Biogeosciences, 20, 997–1009, https://doi.org/10.5194/bg-20-997-2023, https://doi.org/10.5194/bg-20-997-2023, 2023
Short summary
Short summary
Large numbers of marine organisms such as zooplankton and fish perform daily vertical migration between the surface (at night) and the depths (in the daytime). This fascinating migration is important for the carbon cycle, as these organisms actively bring carbon to depths where it is stored away from the atmosphere for a long time. Here, we quantify the contributions of different animals to this carbon drawdown and storage and show that fish are important to the biological carbon pump.
Alastair J. M. Lough, Alessandro Tagliabue, Clément Demasy, Joseph A. Resing, Travis Mellett, Neil J. Wyatt, and Maeve C. Lohan
Biogeosciences, 20, 405–420, https://doi.org/10.5194/bg-20-405-2023, https://doi.org/10.5194/bg-20-405-2023, 2023
Short summary
Short summary
Iron is a key nutrient for ocean primary productivity. Hydrothermal vents are a source of iron to the oceans, but the size of this source is poorly understood. This study examines the variability in iron inputs between hydrothermal vents in different geological settings. The vents studied release different amounts of Fe, resulting in plumes with similar dissolved iron concentrations but different particulate concentrations. This will help to refine modelling of iron-limited ocean productivity.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
Short summary
Short summary
The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
Biogeosciences, 19, 5807–5835, https://doi.org/10.5194/bg-19-5807-2022, https://doi.org/10.5194/bg-19-5807-2022, 2022
Short summary
Short summary
Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Abigale M. Wyatt, Laure Resplandy, and Adrian Marchetti
Biogeosciences, 19, 5689–5705, https://doi.org/10.5194/bg-19-5689-2022, https://doi.org/10.5194/bg-19-5689-2022, 2022
Short summary
Short summary
Marine heat waves (MHWs) are a frequent event in the northeast Pacific, with a large impact on the region's ecosystems. Large phytoplankton in the North Pacific Transition Zone are greatly affected by decreased nutrients, with less of an impact in the Alaskan Gyre. For small phytoplankton, MHWs increase the spring small phytoplankton population in both regions thanks to reduced light limitation. In both zones, this results in a significant decrease in the ratio of large to small phytoplankton.
Margot C. F. Debyser, Laetitia Pichevin, Robyn E. Tuerena, Paul A. Dodd, Antonia Doncila, and Raja S. Ganeshram
Biogeosciences, 19, 5499–5520, https://doi.org/10.5194/bg-19-5499-2022, https://doi.org/10.5194/bg-19-5499-2022, 2022
Short summary
Short summary
We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.
Emily J. Zakem, Barbara Bayer, Wei Qin, Alyson E. Santoro, Yao Zhang, and Naomi M. Levine
Biogeosciences, 19, 5401–5418, https://doi.org/10.5194/bg-19-5401-2022, https://doi.org/10.5194/bg-19-5401-2022, 2022
Short summary
Short summary
We use a microbial ecosystem model to quantitatively explain the mechanisms controlling observed relative abundances and nitrification rates of ammonia- and nitrite-oxidizing microorganisms in the ocean. We also estimate how much global carbon fixation can be associated with chemoautotrophic nitrification. Our results improve our understanding of the controls on nitrification, laying the groundwork for more accurate predictions in global climate models.
Zuozhu Wen, Thomas J. Browning, Rongbo Dai, Wenwei Wu, Weiying Li, Xiaohua Hu, Wenfang Lin, Lifang Wang, Xin Liu, Zhimian Cao, Haizheng Hong, and Dalin Shi
Biogeosciences, 19, 5237–5250, https://doi.org/10.5194/bg-19-5237-2022, https://doi.org/10.5194/bg-19-5237-2022, 2022
Short summary
Short summary
Fe and P are key factors controlling the biogeography and activity of marine N2-fixing microorganisms. We found lower abundance and activity of N2 fixers in the northern South China Sea than around the western boundary of the North Pacific, and N2 fixation rates switched from Fe–P co-limitation to P limitation. We hypothesize the Fe supply rates and Fe utilization strategies of each N2 fixer are important in regulating spatial variability in community structure across the study area.
Claudia Eisenring, Sophy E. Oliver, Samar Khatiwala, and Gregory F. de Souza
Biogeosciences, 19, 5079–5106, https://doi.org/10.5194/bg-19-5079-2022, https://doi.org/10.5194/bg-19-5079-2022, 2022
Short summary
Short summary
Given the sparsity of observational constraints on micronutrients such as zinc (Zn), we assess the sensitivities of a framework for objective parameter optimisation in an oceanic Zn cycling model. Our ensemble of optimisations towards synthetic data with varying kinds of uncertainty shows that deficiencies related to model complexity and the choice of the misfit function generally have a greater impact on the retrieval of model Zn uptake behaviour than does the limitation of data coverage.
Yoshikazu Sasai, Sherwood Lan Smith, Eko Siswanto, Hideharu Sasaki, and Masami Nonaka
Biogeosciences, 19, 4865–4882, https://doi.org/10.5194/bg-19-4865-2022, https://doi.org/10.5194/bg-19-4865-2022, 2022
Short summary
Short summary
We have investigated the adaptive response of phytoplankton growth to changing light, nutrients, and temperature over the North Pacific using two physical-biological models. We compare modeled chlorophyll and primary production from an inflexible control model (InFlexPFT), which assumes fixed carbon (C):nitrogen (N):chlorophyll (Chl) ratios, to a recently developed flexible phytoplankton functional type model (FlexPFT), which incorporates photoacclimation and variable C:N:Chl ratios.
Jens Terhaar, Thomas L. Frölicher, and Fortunat Joos
Biogeosciences, 19, 4431–4457, https://doi.org/10.5194/bg-19-4431-2022, https://doi.org/10.5194/bg-19-4431-2022, 2022
Short summary
Short summary
Estimates of the ocean sink of anthropogenic carbon vary across various approaches. We show that the global ocean carbon sink can be estimated by three parameters, two of which approximate the ocean ventilation in the Southern Ocean and the North Atlantic, and one of which approximates the chemical capacity of the ocean to take up carbon. With observations of these parameters, we estimate that the global ocean carbon sink is 10 % larger than previously assumed, and we cut uncertainties in half.
Natasha René van Horsten, Hélène Planquette, Géraldine Sarthou, Thomas James Ryan-Keogh, Nolwenn Lemaitre, Thato Nicholas Mtshali, Alakendra Roychoudhury, and Eva Bucciarelli
Biogeosciences, 19, 3209–3224, https://doi.org/10.5194/bg-19-3209-2022, https://doi.org/10.5194/bg-19-3209-2022, 2022
Short summary
Short summary
The remineralisation proxy, barite, was measured along 30°E in the southern Indian Ocean during early austral winter. To our knowledge this is the first reported Southern Ocean winter study. Concentrations throughout the water column were comparable to observations during spring to autumn. By linking satellite primary production to this proxy a possible annual timescale is proposed. These findings also suggest possible carbon remineralisation from satellite data on a basin scale.
Zhibo Shao and Ya-Wei Luo
Biogeosciences, 19, 2939–2952, https://doi.org/10.5194/bg-19-2939-2022, https://doi.org/10.5194/bg-19-2939-2022, 2022
Short summary
Short summary
Non-cyanobacterial diazotrophs (NCDs) may be an important player in fixing N2 in the ocean. By conducting meta-analyses, we found that a representative marine NCD phylotype, Gamma A, tends to inhabit ocean environments with high productivity, low iron concentration and high light intensity. It also appears to be more abundant inside cyclonic eddies. Our study suggests a niche differentiation of NCDs from cyanobacterial diazotrophs as the latter prefers low-productivity and high-iron oceans.
Coraline Leseurre, Claire Lo Monaco, Gilles Reverdin, Nicolas Metzl, Jonathan Fin, Claude Mignon, and Léa Benito
Biogeosciences, 19, 2599–2625, https://doi.org/10.5194/bg-19-2599-2022, https://doi.org/10.5194/bg-19-2599-2022, 2022
Short summary
Short summary
Decadal trends of fugacity of CO2 (fCO2), total alkalinity (AT), total carbon (CT) and pH in surface waters are investigated in different domains of the southern Indian Ocean (45°S–57°S) from ongoing and station observations regularly conducted in summer over the period 1998–2019. The fCO2 increase and pH decrease are mainly driven by anthropogenic CO2 estimated just below the summer mixed layer, as well as by a warming south of the polar front or in the fertilized waters near Kerguelen Island.
Priscilla Le Mézo, Jérôme Guiet, Kim Scherrer, Daniele Bianchi, and Eric Galbraith
Biogeosciences, 19, 2537–2555, https://doi.org/10.5194/bg-19-2537-2022, https://doi.org/10.5194/bg-19-2537-2022, 2022
Short summary
Short summary
This study quantifies the role of commercially targeted fish biomass in the cycling of three important nutrients (N, P, and Fe), relative to nutrients otherwise available in water and to nutrients required by primary producers, and the impact of fishing. We use a model of commercially targeted fish biomass constrained by fish catch and stock assessment data to assess the contributions of fish at the global scale, at the time of the global peak catch and prior to industrial fishing.
Rebecca Chmiel, Nathan Lanning, Allison Laubach, Jong-Mi Lee, Jessica Fitzsimmons, Mariko Hatta, William Jenkins, Phoebe Lam, Matthew McIlvin, Alessandro Tagliabue, and Mak Saito
Biogeosciences, 19, 2365–2395, https://doi.org/10.5194/bg-19-2365-2022, https://doi.org/10.5194/bg-19-2365-2022, 2022
Short summary
Short summary
Dissolved cobalt is present in trace amounts in seawater and is a necessary nutrient for marine microbes. On a transect from the Alaskan coast to Tahiti, we measured seawater concentrations of dissolved cobalt. Here, we describe several interesting features of the Pacific cobalt cycle including cobalt sources along the Alaskan coast and Hawaiian vents, deep-ocean particle formation, cobalt activity in low-oxygen regions, and how our samples compare to a global biogeochemical model’s predictions.
Nicolas Metzl, Claire Lo Monaco, Coraline Leseurre, Céline Ridame, Jonathan Fin, Claude Mignon, Marion Gehlen, and Thi Tuyet Trang Chau
Biogeosciences, 19, 1451–1468, https://doi.org/10.5194/bg-19-1451-2022, https://doi.org/10.5194/bg-19-1451-2022, 2022
Short summary
Short summary
During an oceanographic cruise conducted in January 2020 in the south-western Indian Ocean, we observed very low CO2 concentrations associated with a strong phytoplankton bloom that occurred south-east of Madagascar. This biological event led to a strong regional CO2 ocean sink not previously observed.
Cited articles
Abraham, K., Opfergelt, S., Fripiat, F., Cavagna, A.-J., de Jong, J. T. M., Foley, S. F., André, L., and Cardinal, D.: δ30Si and δ29Si Determination on USGS BHVO-1 and BHVO-2 Reference Materials with a New Configuration on a Nu Plasma Multi-Collector ICP-MS, Geostand. Geoanal. Res., 32, 193–202, 2008.
Assmy P., Smetacek V., Montresor M., Klaas C., Henjes J., Strass V. H., Arrieta J. M., Bathmann U., Berg G. M., Breitbarth E., Cisewski B., Friedrich L., Fuchs N., Herndl G. J., Jansen S., Krägefsky S., Latasa M., Peeken I., Röttgers R., Scharek R., Schüller S. E., Steigenberger S., Webb A., and Wolf-Gladrow D.: Thick-shelled, grazed protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current, PNAS, 110, 20633, https://doi.org/10.1073/pnas.1309345110, 2013.
Baines, S., Twining B. S., Brzezinski M. A., Nelson D. M., and Fisher N. S.: Causes and biogeochemical implications of regional differences in silicification of marine diatoms, Global Biogeochem. Cy., 24, GB4031, https://doi.org/10.1029/2010GB003856, 2010
Blain, S., Tréguer, P., Belviso, S., Bucciarelli, E., Denis, M., Desabre, S., Fiala, M., Martin Jézéquel, V., Le Fèvre, J., Mayzaud, P., Marty, J.-C., and Razouls, S.: A biogeochemical study of the island mass effect in the context of the iron hypothesis: Kerguelen Islands, Southern Ocean, Deep-Sea Research Pt. I, 48, 163–187, 2001.
Blain, S., Quéguiner, B., Armand, L., Belviso, S., Bombled, B., Bopp, L., Bowie, A., Brunet, C., Brussaard, C., Carlotti, F., Christaki, U., Corbière, A., Durand, I., Ebersbach, F., Fuda, J.-L., Garcia, N., Gerringa, L., Griffiths, B., Guigue, C., Guillerm, C., Jacquet, S., Jeandel, C., Laan, P., Lefèvre, D., Lo Monaco, C., Malits, A., Mosseri, J., Obernosterer, I., Park, Y.-H., Picheral, M., Pondaven, P., Remenyi, T., Sandroni, V., Sarthou, G., Savoye, N., Scouarnec, L., Souhaut, M., Thuiller, D., Timmermans, K., Trull, T., Uitz, J., van Beek, P., Veldhuis, M., Vincent, D., Viollier, E., Vong, L., and Wagener, T.: Effect of natural iron fertilization on carbon sequestration in the Southern Ocean, Nature, 446, 1070–1075, https://doi.org/10.1038/nature05700, 2007.
Blain, S., Renaut, S., Xing, X., Claustre, H., and Guinet, C.: Instrumented elephant seals reveal the seasonality in chlorophyll and light-mixing regime in the iron-fertilized Southern Ocean, Geophys. Res. Lett., 40, 1–5, https://doi.org/10.1002/2013GL058065, 2013.
Blain, S., Capparos, J., Guéneuguès, A., Obernosterer, I., and Oriol, L.: Distributions and stoichiometry of dissolved nitrogen and phosphorus in the iron-fertilized region near Kerguelen (Southern Ocean), Biogeosciences, 12, 623–635, https://doi.org/10.5194/bg-12-623-2015, 2015.
Bowie, A. R., van der Merwe, P., Quéroué, F., Trull, T., Fourquez, M., Planchon, F., Sarthou, G., Chever, F., Townsend, A. T., Obernosterer, I., Sallée, J.-B., and Blain, S.: Iron budgets for three distinct biogeochemical sites around the Kerguelen Archipelago (Southern Ocean) during the natural fertilisation study, KEOPS-2, Biogeosciences, 12, 4421–4445, https://doi.org/10.5194/bg-12-4421-2015, 2015.
Boyd, P. W and Trull, T. W.: Understanding the export of biogenic particles in oceanic waters: Is there concensus?, Prog. Oceanogr., 72, 276–312, 2007.
Brzezinski, M. A., Nelson, D. M., Franck, V. M., and Sigmon, D. E.: Silicon dynamics within an intense open-ocean diatom bloom in the Pacific sector of the Southern Ocean, Deep-Sea Res. Pt. II, 48, 3997–4018, 2001.
Brzezinski, M. A. and Jones J. L.: Coupling of the distribution of silicon isotopes to the meridional overturning circulation of the North Atlantic Ocean, Deep-Sea Res. PT. II, 1, 79–88, 2015.
Buesseler, K. O.: The decoupling of production and particulate export in the surface ocean, Global Biogeochem. Cy., 12, 297–310, 1998.
Cao, Z., Frank, M., Dai, M., Grasse, P., and Ehlert, C.: Silicon isotope constraints on sources and utilization od silicic acid in the northern South China Sea, Geochim. Cosmochim. Ac., 97, 88–104, 2012.
Cardinal, D., Alleman, L. Y., De Jong, J., Ziegler, K., and André, L.: Isotopic composition of silicon measured by multicollector plasma source mass spectrometry in dry plasma mode, J. Anal. Atom. Spectrom., 18, 213–218, 2003.
Cardinal, D., Alleman, L. Y., Dehairs, F., Savoye, N., Trull, T. W., and André, L.: Relevance of silicon isotopes to Si-nutrient utilization and Si-source assessment in Antarctic waters, Global Biogeochem. Cy., 19, GB2007, https://doi.org/10.1029/2004GB002364, 2005.
Cardinal, D., Savoye, N., Trull, T. W., Dehairs, F., Kopczynska, E. E., Fripiat, F., Tison, J.-L., and André, L.: Silicon isotopes in spring Southern Ocean diatoms: Large zonal changes despite homogeneity among size fractions, Mar. Chem., 106, 46–62, 2007.
Cavagna, A.-J., Fripiat, F., Dehairs, F., Wolf-Gladrow, D., Cisewski, B., Savoye, N., André, L., and Cardinal, D.: Silicon uptake and supply during a Southern Ocean iron fertilization experiment (EIFEX) tracked by Si isotopes, Limnol. Oceanogr., 56, 147–160, https://doi.org/10.4319/lo.2011.56.1.0147, 2011.
Cavagna, A. J., Fripiat, F., Elskens, M., Mangion, P., Chirurgien, L., Closset, I., Lasbleiz, M., Florez-Leiva, L., Cardinal, D., Leblanc, K., Fernandez, C., Lefèvre, D., Oriol, L., Blain, S., Quéguiner, B., and Dehairs, F.: Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean, Biogeosciences, 12, 6515–6528, https://doi.org/10.5194/bg-12-6515-2015, 2015.
Closset, I., Lasbleiz, M., Leblanc, K., Quéguiner, B., Cavagna, A.-J., Elskens, M., Navez, J., and Cardinal, D.: Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches, Biogeosciences, 11, 5827–5846, https://doi.org/10.5194/bg-11-5827-2014, 2014.
Closset, I., Cardinal, D., Bray, S., Thil, F., Djouraev, I., Rigual-Hernandez, A. S., and Trull, T.: Seasonal variations, origin and fate of settling diatoms in the Southern Ocean tracked by silicon isotope records in deep sediment traps, Global Biogeochem. Cy., 29, 1495–1510, https://doi.org/10.1002/2015GB005180, 2015.
De Baar, H. J. W., Boys, P. W., Coale, K. H., Landry, M. R., Tsuda, A., Assmy, P., Bakker, D. C. E., Bozec, Y., Barber, R. T., Brzezinski, M. A., Buesseler, K. O., Boyé, M., Croot, P. L., Gervais, F., Gorbunov, M. Y., Harrison, P. J., Hiscock, W. T., Laan, P., Lancelot, C., Law, C. S., Levasseur, M., Marchetti, A., Millero, F. J., Nishioka, J., Nojiri, Y., van Oijen, T., Riebesell, U., Rijkenberg, M. J. A., Saito, H., Takeda, S., Timmermans, K. R., Veldhuis, M. J. W., Waite, A. M., and Wong, C.-S.: Synthesis of iron fertilization experiments: From the Iron Age in the Age of Enlightenment, J. Geophys. Res., 110, C09S16, https://doi.org/10.1029/2004JC002601, 2005.
De Brauwere, A., Fripiat, F., Cardinal, D., Cavagna, A.-J., De Ridder, F., André, L., and Elskens, M.: Isotopic model of oceanic silicon cycling: The Kerguelen Plateau case study, Deep-Sea Res. Pt. I, 70, 42–59, 2012.
Dehairs, F., Fripiat, F., Cavagna, A.-J., Trull, T. W., Fernandez, C., Davies, D., Roukaerts, A., Fonseca Batista, D., Planchon, F., and Elskens, M.: Nitrogen cycling in the Southern Ocean Kerguelen Plateau area: evidence for significant surface nitrification from nitrate isotopic compositions, Biogeosciences, 12, 1459–1482, https://doi.org/10.5194/bg-12-1459-2015, 2015.
De La Rocha, C. L., Brzezinski, M. A., and DeNiro, M. J.: Purification, Recovery, and Laser-Driven Fluorination of Silicon from Dissolved and Particulate Silica for the Measurement of Natural Stable Isotope Abundances, Anal. Chem., 68, 3746–3750, 1996.
De La Rocha, C. L., Brzezinski, M. A., and DeNiro, M. J.: Fractionation of silicon isotopes by marine diatoms during biogenic silica formation, Geochim. Cosmochim. Ac., 61, 5051–5056, 1997.
De La Rocha, C. L., Brzezinski, M. A., DeNiro, M. J., and Shemesh, A.: Silicon-isotope composition of diatoms as an indicator of past oceanic change, Nature, 395, 680–683, 1998.
De La Rocha, C. L., Hutchins, D. A., Brzezinski, M. A., and Zhang, Y.: Effects of iron and zinc deficiency on elemental composition and silica production by diatoms, Mar. Ecol.-Prog. Ser., 195, 71–79, 2000.
De Souza, G. F., Reynolds, B. C., Rickli, J., Frank, M., Saito, M. A., Gerringa, L. J. A., and Bourdon, B.: Southern Ocean control of silicon stable isotope distribution in the deep Atlantic Ocean, Global Biogeochem. Cy., 26, GB2035, https://doi.org/10.1029/2011GB004141, 2012.
Demarest, M. S., Brzezinski, M. A., and Beucher, C. P.: Fractionation of silicon isotopes during biogenic silica dissolution, Geochim. Cosmochim. Ac., 73, 5572–5583, https://doi.org/10.1016/j.gca.2009.06.019, 2009.
Dufour, C. O., Griffies, S. M., De Souza, G. F., Frenger, I., Morrison, A. K., Palter, J. B., Sarmiento, J. L., Galbraith, E. D., Dunne, J. P., Anderson, W. G., and Salter, R. D.: Role of Mesoscale Eddies in Cross-Frontal Transport of Heat and Biogeochemical Tracers in the Southern Ocean, J. Phys. Oceanogr., 45, 3057–3081, https://doi.org/10.1175/JPO-D-14-0240.1, 2015.
Dugdale, R. C., Wilkerson, F. P., and Minas, H. J.: The role of a silicate pump in driving new production, Deep-Sea Res. Pt. I, 42, 697–719, 1995.
Ehlert, C., Grasse, P., and Frank, M.: Changes in silicate utilization and upwelling intensity off Peru since the Last Glacial Maximum – insights from silicon and neodymium isotopes, Quaternary Sci. Rev., 72, 18–35, 2013.
Fripiat, F., Cavagna, A.-J., Savoye, N., Dehairs, F., André, L., and Cardinal, D.: Isotopic constraints on the Si-biogeochemical cycle of the Antarctic Zone in the Kerguelen area (KEOPS), Mar. Chem., 123, 11–22, https://doi.org/10.1016/j.marchem.2010.08.005, 2011a.
Fripiat, F., Cavagna, A.-J., Dehairs, F., Speich, S., André, L., and Cardinal, D.: Silicon pool dynamics and biogenic silica export in the Southern Ocean inferred from Si-isotopes, Ocean Sci., 7, 533–547, https://doi.org/10.5194/os-7-533-2011, 2011b.
Fripiat, F., Leblanc, K., Elskens, M., Cavagna, A.-J., Armand, L., André, L., Dehairs, F., and Cardinal, D.: Efficient silicon recycling in summer in both the Polar Frontal and Subantarctic Zones of the Southern Ocean, Mar. Ecol.-Prog. Ser., 435, 47–61, https://doi.org/10.3354/meps09237, 2011c.
Fripiat, F., Cavagna, A.-J., Dehairs, F., de Brauwere, A., André, L., and Cardinal, D.: Processes controlling the Si-isotopic composition in the Southern Ocean and application for paleoceanography, Biogeosciences, 9, 2443–2457, https://doi.org/10.5194/bg-9-2443-2012, 2012.
Fry, B.: Stable Isotope Ecology, Springer, New York, 308 pp., 2006.
Georg, R. B., Reynolds, B. C., Frank, M., and Halliday, A. N.: New sample preparation techniques for the determination of Si isotopic compositions using MC-ICPMS, Chem. Geol., 235, 95–104, 2006.
Gille, S. T., Carranza, M. M., Cambra, R., and Morrow, R.: Wind-induced upwelling in the Kerguelen Plateau region, Biogeosciences, 11, 6389–6400, https://doi.org/10.5194/bg-11-6389-2014, 2014.
Grasse, P., Brzezinski, M. A., Cardinal, D., de Souza, G. F., Andersson, P., Closset, I., Cao, Z., Dai, M., Ehlert, C., Estrade, N., François, R., Frank, M., Jiang, G., Jones, J. L., Kooijman, E., Liu, Q., Lu, D., Pahnke, K., Ponzervera, E., Schmitt, M., Sun, X., Sutton, J. N., Thil, F., Weis, D., Wetzel, F., Zhang, A., and Zhang, J.: GEOTRACES Intercalibration of the Stable Isotope Composition of Dissolved Silicic Acid in Seawater, J. Anal. Atom. Spect., sumitted, 2016.
Grasshoff, K., Kremling, K., and Ehrhardt, M.: Methods of Seawater Analysis 3rd edition completely Revised and Extended edition, Wiley-VCH, ISBN 3-527-29589-5, 1999.
Hughes, H. J., Delvigne, C., Korntheuer, M., De Jong, J., André, L., and Cardinal, D.: Controlling the mass bias introduced by anionic and organic matrices in silicon isotopic measurements, J. Anal. Atom. Spectrom., 26, 1892–1896, 2011.
Jacquet, S. H. M., Dehairs, F., Lefèvre, D., Cavagna, A. J., Planchon, F., Christaki, U., Monin, L., André, L., Closset, I., and Cardinal, D.: Early spring mesopelagic carbon remineralization and transfer efficiency in the naturally iron-fertilized Kerguelen area, Biogeosciences, 12, 1713–1731, https://doi.org/10.5194/bg-12-1713-2015, 2015.
Karl, D. M. and Tien, G.: MAGIC: A sensitive and precise method for measuring dissolved phosphorus in aquatic environments, Limnol. Oceanogr., 37, 105–116, 1992.
Laurenceau-Cornec, E. C., Trull, T. W., Davies, D. M., Bray, S. G., Doran, J., Planchon, F., Carlotti, F., Jouandet, M.-P., Cavagna, A.-J., Waite, A. M., and Blain, S.: The relative importance of phytoplankton aggregates and zooplankton fecal pellets to carbon export: insights from free-drifting sediment trap deployments in naturally iron-fertilised waters near the Kerguelen Plateau, Biogeosciences, 12, 1007–1027, https://doi.org/10.5194/bg-12-1007-2015, 2015.
Lasbleiz, M., Leblanc, K., Blain, S., Ras, J., Cornet-Barthaux, V., Hélias Nunige, S., and Quéguiner, B.: Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean, Biogeosciences, 11, 5931–5955, https://doi.org/10.5194/bg-11-5931-2014, 2014.
Mongin, M., Molina, E., and Trull, T. W.: Seasonality and scale of the Kerguelen plateau phytoplankton bloom: A remote sensing and modeling analysis of the influence of natural iron fertilization in the Southern Ocean, Deep-Sea Res. Pt. II, 55, 880–892, 2008.
Mosseri, J., Quéguiner, B., Armand, L., and Cornet-Barthaux, V.: Impact of iron on silicon utilization by diatoms in the Southern Ocean: A case study of Si/N cycle decoupling in a naturally iron-enriched area, Deep-Sea Res. Pt. II, 55, 801–819, 2008.
Nelson, D. M., Brzezinski, M. A., Sigmon, D. E., and Franck, V. M.: A seasonal progression of Si limitation in the Pacific sector of the Southern Ocean, Deep-Sea Res. Pt. II, 48, 3973–3995, 2001.
Nelson, D. M., Anderson, R. F., Barber, R. T., Brzezinski, M. A., Buesseler, K. O., Chase, Z., Collier, R. W., Dickson, M.-L., François, R., Hiscock, M. R., Honjo, S., Marra, J., Martin, W. R., Sambrotto, R. N., Sayles, F. L., and Sigmon, D. E.: Vertical budgets for organic carbon and biogenic silica in the Pacific sector of the Southern Ocean, 1996–1998, Deep-Sea Res. Pt. II, 49, 1645–1674, 2002.
Opfergelt, S. and Delmelle, P.: silicon isotopes and continental weathering processes: Assessing controls on Si transfer to the ocean, C. R. Geosci., 344, 723–738, https://doi.org/10.1016/j.crte.2012.09.006, 2012.
Park, Y.-H., Fuda, J.-L., Durand, I., and Naveira Garabato, A. C.: Internal tides and vertical mixing over the Kerguelen Plateau, Deep-Sea Res. Pt. II, 55, 582–593, 2008b.
Park, Y.-H., Durand, I., Kestenare, E., Rougier, G., Zhou, M., d'Ovidio, F., Cotté, C., and Lee, J.-H.: Polar Front around the Kerguelen Islands: An up-to-date determination and associated circulation of surface/subsurface water, J. Geophys. Res.-Oceans, 119, 1–18, https://doi.org/10.1002/2014JC010061, 2014.
Parslow, J. S., Boyd, P. W., Rintoul, S. R., and Griffiths, F. B.: A persistent subsurface chlorophyll maximum in the Interpolar Frontal Zone south of Australia: Seasonal progression and implications for phytoplankton-light-nutrient interactions, J. Geophys. Res., 106, 31543–31557, 2001.
Planchon, F., Ballas, D., Cavagna, A.-J., Bowie, A. R., Davies, D., Trull, T., Laurenceau-Cornec, E. C., Van Der Merwe, P., and Dehairs, F.: Carbon export in the naturally iron-fertilized Kerguelen area of the Southern Ocean based on the 234Th approach, Biogeosciences, 12, 3831–3848, https://doi.org/10.5194/bg-12-3831-2015, 2015.
Pollard, R. T., Tréguer, P., and Read, J.: Quantifying nutrient supply to the Southern Ocean, J. Geophys. Res., 111, C05011, https://doi.org/10.1029/2005JC003076, 2006.
Pollard, R. T., Salter, I., Sanders, R. J., Lucas, M. I., Moore, C. M., Mills, R. A., Statham, P. J., Allen, J. T., Baker, A. R., Bakker, D. C. E., Charette, M. A., Fielding, S., Fones, G. R., French, M., Hickman, A. E., Holland, R. J., Hughes, J. A., Jickells, T. D., Lampitt, R. S., Morris, P. J., Nédélec, F. H., Nielsdóttir, M., Planquette, H., Popova, E. E., Poulton, A. J., Read, J. F., Seeyave, S., Smith, T., Stinchcombe, M., Taylor, S., Thomalla, S., Venables, H. J., Williamson, R., and Zubkov, M. V.: Southern Ocean deep-water carbon export enhanced by natural iron fertilization, Nature 457, 577–580, https://doi.org/10.1038/nature07716, 2009.
Pondaven, P., Ragueneau, O., Tréguer, P., Hauvespre, A., Dezileau, L., and Reyss, J. L.: Resolving the “opal paradox” in the Southern Ocean, Nature, 405, 168–172, 2000.
Quéroué, F., Sarthou, G., Planquette, H. F., Bucciarelli, E., Chever, F., van der Merwe, P., Lannuzel, D., Townsend, A. T., Cheize, M., Blain, S., d'Ovidio, F., and Bowie, A. R.: High variability in dissolved iron concentrations in the vicinity of the Kerguelen Islands (Southern Ocean), Biogeosciences, 12, 3869–3883, https://doi.org/10.5194/bg-12-3869-2015, 2015.
Ragueneau, O., Tréguer, P., Leynaert, A., Anderson, R. F., Brzezinski, M. A., DeMaster, D. J., Dugdale, R. C., Dymond, J., Fischer, G., François, R., Heinze, C., Maier-Reimer, E., Martin-Jézéquel, V., Nelson, D. M., and Quéguiner, B.: A review of the Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy, Global Planet. Change, 26, 317–365, 2000.
Ragueneau, O., Savoye, N., Del Amo, Y., Cotton, J., Tardiveau, B., and Leynaert, A.: A new method for the measurement of biogenic silica in suspended matter of coastal waters: using Si : Al ratios to correct for the mineral interference, Cont. Shelf Res., 25, 697–710, 2005.
Rembauville, M., Blain, S., Armand, L., Quéguiner, B., and Salter, I.: Export fluxes in a naturally iron-fertilized area of the Southern Ocean – Part 2: Importance of diatom resting spores and faecal pellets for export, Biogeosciences, 12, 3171–3195, https://doi.org/10.5194/bg-12-3171-2015, 2015.
Rembauville, M., Blain, S., Caparros, J., and Salter, I.: Particulate matter stoichiometry driven by microplankton community structure in summer in the Indian sector of the Southern Ocean, Limnol. Oceanogr., 61, 1301–1321, https://doi.org/10.1002/lno.10291, 2016.
Reynolds, B. C., Frank, M., and Halliday, A. N.: Silicon isotope fractionation during nutrient utilization in the North Pacific, Earth Planet. Sci. Lett., 244, 431–443, 2006.
Reynolds, B. C., Aggarwal, J., André, L., Baxter, D., Beucher, C., Brzezinski, M. A., Engström, E., Georg, R. B., Land, M., Leng, M. J., Opfergelt, S., Rodushkin, I., Sloane, H. J., van den Boorn, S. H. J. M., Vroon, P. Z., and Cardinal, D.: An inter-laboratory comparison of Si isotope reference materials, J. Anal. Atom. Spectrom., 22, 561–568, https://doi.org/10.1039/b616755a, 2007.
Sanial, V., van Beek, P., Lansard, B., Souhaut, M., Kestenare, E., d'Ovidio, F., Zhou, M., and Blain, S.: Use of Ra isotopes to deduce rapid transfer of sediment-derived inputs off Kerguelen, Biogeosciences, 12, 1415–1430, https://doi.org/10.5194/bg-12-1415-2015, 2015.
Sarmiento, J. L., Gurber, N., Brzezinski, M. A., and Dunne, J. P.: High-latitude controls of thermocline nutrients and low latitude biological productivity, Nature, 427, 56–60, 2004.
Sutton, J. N., Varela, D. E., Brzezinski, M. A., and Beucher, C. P.: Species-dependent silicon isotope fractionation by marine diatoms, Geochim. Cosmochim. Ac., 104, 300–309, 2013.
Takahashi, T., Sutherland, S. C., Wanninkhof, R., Sweeney, C., Feely, R. A., Chipman, D. W., Hales, B., Friederich, G., Chavez, F., Sabine, C., Watson, A., Bakker, D. C. E., Schuster, U., Metzl, N., Yoshikawa-Inoue, H., Ishii, M., Midorikawa, T., Nojiri, Y., Körtzinger, A., Steinhoff, T., Hoppema, M., Olafsson, J., Arnarson, T. S., Tilbrook, B., Johannessen, T., Olsen, A., Bellerby, R., Wong, C. S., Delille, B., Bates, N. R., and de Baar, H. J. W.: Climatological mean and decadal change in surface ocean pCO2, and net sea-air CO2 flux over the global oceans, Deep-Sea Res. Pt. II, 56, 554–577, https://doi.org/10.1016/j.dsr2.2008.12.009, 2009.
Tréguer, P. J. and De La Rocha, C. L.: The World Ocean Silica Cycle, Annu. Rev. Mar. Sci., 5, 477–501, 2013.
Trull, T., Rintoul, S. R., Hadfield, M., and Abraham, E. R.: Circulation and seasonal evolution of polar waters south of Australia: Implications for iron fertilization of the Southern Ocean, Deep-Sea Res. Pt. II, 48, 2439–2466, 2001.
Trull, T. W., Davies, D. M., Dehairs, F., Cavagna, A.-J., Lasbleiz, M., Laurenceau-Cornec, E. C., d'Ovidio, F., Planchon, F., Leblanc, K., Quéguiner, B., and Blain, S.: Chemometric perspectives on plankton community responses to natural iron fertilisation over and downstream of the Kerguelen Plateau in the Southern Ocean, Biogeosciences, 12, 1029–1056, https://doi.org/10.5194/bg-12-1029-2015, 2015.
Uitz, J., Claustre, H., Griffiths, F. B., Ras, J., Garcia, N., and Sandroni, V.: A phytoplankton class-specific primary production model applied to the Kerguelen Islands region (Southern Ocean), Deep-Sea Res. Pt. I, 56, 541–560, 2009.
Van den Boorn, S. H. J. M., Vroon, P. Z., and Van Bergen, M. J.: Sulfur-induced offsets in MC-ICP-MS silicon-isotope measurements, J. Anal. Atom. Spectrom., 24, 1111–1114, 2009.
Varela, D. E., Pride, C. J., and Brzezinski, M. A.: Biological fractionation of silicon isotopes in Southern Ocean surface waters, Global Biogeochem. Cy., 18, GB1047, https://doi.org/10.1029/2003GB002140, 2004.
Wetzel, F., de Souza, G. F., and Reynolds, B. C.: What controls silicon isotope fractionation during dissolution of diatom opal?, Geochim. Cosmochim. Ac., 131, 128–137, https://doi.org/10.1016/j.gca.2014.01.028, 2014.
Zhou, M., Zhu, Y., d'Ovidio, F., Park, Y.-H., Durand, I., Kestenare, E., Sanial, V., Van-Beek, P., Queguiner, B., Carlotti, F., and Blain, S.: Surface currents and upwelling in Kerguelen Plateau regions, Biogeosciences Discuss., 11, 6845–6876, https://doi.org/10.5194/bgd-11-6845-2014, 2014.
Short summary
Isotopic measurements were used to investigate the seasonal evolution of the silicon (Si) biogeochemical cycle in a naturally iron-fertilized area of the Southern Ocean. When comparing data from early spring and summer periods, the relationship between Si depletion, biogenic silica production, and their isotopic composition appears decoupled in this region. Considering these results, we refined the seasonal net Si production that was mainly sustained by surface phytoplankton populations.
Isotopic measurements were used to investigate the seasonal evolution of the silicon (Si)...
Altmetrics
Final-revised paper
Preprint