Articles | Volume 18, issue 3
https://doi.org/10.5194/bg-18-937-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-18-937-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
10 Feb 2021
Research article |
| 10 Feb 2021
| 10 Feb 2021
Oxygen budget of the north-western Mediterranean deep- convection region
Caroline Ulses
CORRESPONDING AUTHOR
Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse, CNES, CNRS, IRD, UPS, Toulouse, France
Laboratoire d'Aérologie (LA), Université de Toulouse, CNRS, UPS, Toulouse, France
Claude Estournel
Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse, CNES, CNRS, IRD, UPS, Toulouse, France
Marine Fourrier
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche (LOV), 06230 Villefranche-sur-Mer, France
Laurent Coppola
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche (LOV), 06230 Villefranche-sur-Mer, France
Fayçal Kessouri
Laboratoire d'Aérologie (LA), Université de Toulouse, CNRS, UPS, Toulouse, France
Southern California Coastal Water Research Project, Costa Mesa, CA, USA
Dominique Lefèvre
Aix-Marseille Université, Mediterranean Institute of Oceanography (MIO), 13288 Marseille CEDEX 9, France
Patrick Marsaleix
Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse, CNES, CNRS, IRD, UPS, Toulouse, France
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The ocean’s mesopelagic zone (MZ) plays a crucial role in the global carbon cycle. This study combines new and previously published measurements of organic carbon supply and demand collected in August 2018 in the MZ of the subarctic North Pacific Ocean. Supply was insufficient to meet demand in August, but supply entering into the MZ in the spring of 2018 could have met the August demand. Results suggest observations over seasonal timescales may help to close MZ carbon budgets.
Allanah Joy Paul, Mathias Haunost, Silvan Urs Goldenberg, Jens Hartmann, Nicolás Sánchez, Julieta Schneider, Niels Suitner, and Ulf Riebesell
Biogeosciences, 22, 2749–2766, https://doi.org/10.5194/bg-22-2749-2025, https://doi.org/10.5194/bg-22-2749-2025, 2025
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Ocean alkalinity enhancement (OAE) is being assessed for its potential to absorb atmospheric CO2 and store it for a long time. OAE still needs comprehensive assessment of its safety and effectiveness. We studied an idealised OAE application in a natural low-nutrient ecosystem over 1 month. Our results showed that biogeochemical functioning remained mostly stable but that the long-term capability for storing carbon may be limited at high alkalinity concentration.
Alain Fumenia, Hubert Loisel, Rick A. Reynolds, and Dariusz Stramski
Biogeosciences, 22, 2461–2484, https://doi.org/10.5194/bg-22-2461-2025, https://doi.org/10.5194/bg-22-2461-2025, 2025
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Particulate organic nitrogen (PON) plays a central role in ocean biogeochemistry, yet limited in situ data hinder a full understanding of PON variability and associated processes. Measurements of optical properties offer an alternative for assessing PON across diverse marine environments. Our analysis reveals strong relationships between PON and optical properties, supporting a promising means to assess PON from optical measurements performed in situ or conducted from remote-sensing platforms.
Madhavan Girijakumari Keerthi, Olivier Aumont, Lester Kwiatkowski, and Marina Levy
Biogeosciences, 22, 2163–2180, https://doi.org/10.5194/bg-22-2163-2025, https://doi.org/10.5194/bg-22-2163-2025, 2025
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We assessed how well climate models replicate sub-seasonal changes in ocean chlorophyll observed by satellites. Models struggle to capture these variations accurately. Some overestimate fluctuations and their impact on annual chlorophyll variability, while others underestimate them. The underestimation is likely due to limited model resolution, while the overestimation may come from internal model oscillations.
Gesa Schulz, Kirstin Dähnke, Tina Sanders, Jan Penopp, Hermann W. Bange, Rena Czeschel, and Birgit Gaye
EGUsphere, https://doi.org/10.5194/egusphere-2025-1660, https://doi.org/10.5194/egusphere-2025-1660, 2025
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Oxygen minimum zones (OMZs) are low-oxygen ocean areas that deplete nitrogen, a key marine nutrient. Understanding nitrogen cycling in OMZs is crucial for the global nitrogen cycle. This study examined nitrogen cycling in the OMZ of the Bay of Bengal and East Equatorial Indian Ocean, revealing limited mixing between both regions. Surface phytoplankton consumes nitrate, while deeper nitrification recycles nitrogen. In the BoB’s OMZ (100–300 m), nitrogen loss likely occurs via anammox.
Adam V. Subhas, Jennie E. Rheuban, Zhaohui Aleck Wang, Daniel C. McCorkle, Anna P. M. Michel, Lukas Marx, Chloe L. Dean, Kate Morkeski, Matthew G. Hayden, Mary Burkitt-Gray, Francis Elder, Yiming Guo, Heather H. Kim, and Ke Chen
EGUsphere, https://doi.org/10.5194/egusphere-2025-1348, https://doi.org/10.5194/egusphere-2025-1348, 2025
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Ocean alkalinity enhancement (OAE) is a carbon removal approach in which alkaline materials are added to the marine environment, increasing the ocean's ability to store carbon dioxide. We conducted an open-water experiment releasing and tracking a fluorescent water tracer. Under the right conditions, in-water monitoring of OAE does appear to be possible. We conclude with a series of practical recommendations for open-water OAE monitoring.
Jens Terhaar
Biogeosciences, 22, 1631–1649, https://doi.org/10.5194/bg-22-1631-2025, https://doi.org/10.5194/bg-22-1631-2025, 2025
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The ocean is a major natural carbon sink. Despite its importance, estimates of the ocean carbon sink remain uncertain. Here, I present a hybrid model estimate of the ocean carbon sink from 1959 to 2022. By combining ocean models in hindcast mode and Earth system models, I keep the strength of each approach and remove the respective weaknesses. This composite model estimate is similar in magnitude to the best estimate of the Global Carbon Budget but 70 % less uncertain.
Huailin Deng, Koji Suzuki, Ichiro Yasuda, Hiroshi Ogawa, and Jun Nishioka
Biogeosciences, 22, 1495–1508, https://doi.org/10.5194/bg-22-1495-2025, https://doi.org/10.5194/bg-22-1495-2025, 2025
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Iron (Fe) and nitrate are vital for primary production in the North Pacific. Sedimentary Fe is carried by North Pacific Intermediate Water to the North Pacific, but the nutrient return path and its effect on phytoplankton are unclear. By combining Fe and macronutrient fluxes with phytoplankton composition, this study firstly revealed that Fe supply from the subsurface greatly controls diatom abundance and identified the nutrient return path in the subarctic gyre and Kuroshio–Oyashio transition area.
Alexandre Accardo, Rémi Laxenaire, Alberto Baudena, Sabrina Speich, Rainer Kiko, and Lars Stemmann
Biogeosciences, 22, 1183–1201, https://doi.org/10.5194/bg-22-1183-2025, https://doi.org/10.5194/bg-22-1183-2025, 2025
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The open ocean helps mitigate climate change by storing CO2 via the biological carbon pump (BCP), which involves processes like organic carbon production at the surface and transferring it to the deep ocean via various pathways. By deploying an autonomous platform, we found significant marine snow accumulation from the surface to the mesopelagic zone in frontal regions between eddies. We suggest that the coupling of hydrodynamics at eddy edges and biological activity may enhance this process.
Naoya Kanna, Kazutaka Tateyama, Takuji Waseda, Anna Timofeeva, Maria Papadimitraki, Laura Whitmore, Hajime Obata, Daiki Nomura, Hiroshi Ogawa, Youhei Yamashita, and Igor Polyakov
Biogeosciences, 22, 1057–1076, https://doi.org/10.5194/bg-22-1057-2025, https://doi.org/10.5194/bg-22-1057-2025, 2025
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This article presents data on iron and manganese, essential micronutrients for primary producers in the Arctic Laptev and East Siberian seas (LESS). There, observations were made through international cooperation with the Nansen and Amundsen Basin Observational System expedition during the late summer of 2021. The results from this study indicate that the major sources controlling the iron and manganese distributions on the LESS continental margins are river discharge and shelf sediment input.
Ben J. Fisher, Alex J. Poulton, Michael P. Meredith, Kimberlee Baldry, Oscar Schofield, and Sian F. Henley
Biogeosciences, 22, 975–994, https://doi.org/10.5194/bg-22-975-2025, https://doi.org/10.5194/bg-22-975-2025, 2025
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The Southern Ocean is a rapidly warming environment, with subsequent impacts on ecosystems and biogeochemical cycling. This study examines changes in phytoplankton and biogeochemistry using a range of climate models. Under climate change, the Southern Ocean will be warmer, more acidic and more productive and will have reduced nutrient availability by 2100. However, there is substantial variability between models across key productivity parameters. We propose ways of reducing this uncertainty.
Pearse J. Buchanan, Juan J. Pierella Karlusich, Robyn E. Tuerena, Roxana Shafiee, E. Malcolm S. Woodward, Chris Bowler, and Alessandro Tagliabue
EGUsphere, https://doi.org/10.5194/egusphere-2024-3639, https://doi.org/10.5194/egusphere-2024-3639, 2025
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Ammonium is a form of nitrogen that may become more important for growth of marine primary producers (i.e., phytoplankton) in the future. Because some phytoplankton taxa have a greater affinity for ammonium than others, the relative increase in ammonium could cause shifts in community composition. We quantify ammonium enrichment, identify its drivers, and isolate the possible effect on phytoplankton community composition under a high emissions scenario.
David Curbelo-Hernández, Fiz F. Pérez, Melchor González-Dávila, Sergey V. Gladyshev, Aridane G. González, David González-Santana, Antón Velo, Alexey Sokov, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 5561–5589, https://doi.org/10.5194/bg-21-5561-2024, https://doi.org/10.5194/bg-21-5561-2024, 2024
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The study evaluated CO2–carbonate system dynamics in the North Atlantic subpolar gyre during 2009–2019. Significant ocean acidification, largely due to rising anthropogenic CO2 levels, was found. Cooling, freshening, and enhanced convective processes intensified this trend, affecting calcite and aragonite saturation. The findings contribute to a deeper understanding of ocean acidification and improve our knowledge about its impact on marine ecosystems.
Yuye Han, Zvi Steiner, Zhimian Cao, Di Fan, Junhui Chen, Jimin Yu, and Minhan Dai
EGUsphere, https://doi.org/10.5194/egusphere-2024-3492, https://doi.org/10.5194/egusphere-2024-3492, 2024
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Coccolithophore calcite accounts for a major fraction of particulate inorganic carbon (PIC) standing stocks in the western North Pacific, with a markedly higher contribution in the oligotrophic subtropical gyre than in the Kuroshio-Oyashio transition region, which highlights the importance of coccolithophores for PIC production in the pelagic ocean. We also found extensive dissolution of coccolithophore calcite in the oversaturated shallow waters primarily driven by microbial metabolic activity.
Louise Delaigue, Gert-Jan Reichart, Chris Galley, Yasmina Ourradi, and Matthew Paul Humphreys
EGUsphere, https://doi.org/10.5194/egusphere-2024-2853, https://doi.org/10.5194/egusphere-2024-2853, 2024
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Our study analyzed pH in ocean surface waters to understand how they fluctuate with changes in temperature, salinity, and biological activities. We found that temperature mainly controls daily pH variations, but biological processes also play a role, especially in affecting CO2 levels between the ocean and atmosphere. Our research shows how these factors together maintain the balance of ocean chemistry, which is crucial for predicting changes in marine environments.
Medhavi Pandey, Haimanti Biswas, Daniel Birgel, Nicole Burdanowitz, and Birgit Gaye
Biogeosciences, 21, 4681–4698, https://doi.org/10.5194/bg-21-4681-2024, https://doi.org/10.5194/bg-21-4681-2024, 2024
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We analysed sea surface temperature (SST) proxy and plankton biomarkers in sediments that accumulate sinking material signatures from surface waters in the central Arabian Sea (21°–11° N, 64° E), a tropical basin impacted by monsoons. We saw a north–south SST gradient, and the biological proxies showed more organic matter from larger algae in the north. Smaller algae and zooplankton were more numerous in the south. These trends were related to ocean–atmospheric processes and oxygen availability.
Allison Hogikyan and Laure Resplandy
Biogeosciences, 21, 4621–4636, https://doi.org/10.5194/bg-21-4621-2024, https://doi.org/10.5194/bg-21-4621-2024, 2024
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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, not by the direct effect of warming on carbon chemistry and pH. These evaporation and rainfall patterns oppose acidification in saltier parts of the ocean and enhance acidification in fresher regions.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
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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 better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Lyuba Novi, Annalisa Bracco, Takamitsu Ito, and Yohei Takano
Biogeosciences, 21, 3985–4005, https://doi.org/10.5194/bg-21-3985-2024, https://doi.org/10.5194/bg-21-3985-2024, 2024
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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 analyzed its predictability, a strong O2–IPV connection, and predictability for IPV in the tropical Pacific. This opens new routes for monitoring ocean O2 through few observational sites co-located with more abundant IPV measurements in the tropical Pacific.
Winfred Marshal, Jing Xiang Chung, Nur Hidayah Roseli, Roswati Md Amin, and Mohd Fadzil Bin Mohd Akhir
Biogeosciences, 21, 4007–4035, https://doi.org/10.5194/bg-21-4007-2024, https://doi.org/10.5194/bg-21-4007-2024, 2024
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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.
Jens Terhaar
Biogeosciences, 21, 3903–3926, https://doi.org/10.5194/bg-21-3903-2024, https://doi.org/10.5194/bg-21-3903-2024, 2024
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Despite the ocean’s importance in 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 the decadal trends in the multi-model mean ocean carbon sink can be explained by changes in decadal trends in atmospheric CO2. The remaining 20 % are due to internal climate variability and ocean heat uptake.
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
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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
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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
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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
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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
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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
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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
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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.
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
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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
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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
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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.
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
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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
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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.
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
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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
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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.
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
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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
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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
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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
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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.
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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
Cited articles
Allen, J. I., Somerfield, P., and Gilbert, F.: Quantifying uncertainty in high-resolution coupled hydrodynamic-ecosystem models, J. Mar. Syst., 64, 3–14. https://doi.org/10.1016/j.jmarsys.2006.02.010, 2007.
Andrews, O., Buitenhuis, E., Le Quéré, C., Suntharalingam, P. : Biogeochemical modelling of dissolved oxygen in a changing ocean, Phil. Trans. R. Soc. A, 37520160328, https://doi.org/10.1098/rsta.2016.0328, 2017.
Argo: Argo float data and metadata from Global Data Assembly Centre (Argo GDAC), SEANOE, available at: https://doi.org/10.17882/42182 (last access: 19 May 2017), 2020.
Atamanchuk, D., Koelling, J., Send, U., and Wallace, D. W. R.: Rapid transfer of oxygen to the deep ocean mediated by bubbles, Nat. Geosci. 13, 232–237, https://doi.org/10.1038/s41561-020-0532-2, 2020.
Auger, P. A., Diaz, F., Ulses, C., Estournel, C., Neveux, J., Joux, F., Pujo-Pay, M., and Naudin, J. J.: Functioning of the planktonic ecosystem on the Gulf of Lions shelf (NW Mediterranean) during spring and its impact on the carbon deposition: a field data and 3-D modelling combined approach, Biogeosciences, 8, 3231–3261, https://doi.org/10.5194/bg-8-3231-2011, 2011.
Auger, P., Ulses, C., Estournel, C., Stemmann, L., Somot, S., Diaz, F.: Interannual control of plankton communities by deep winter mixing and prey/predator interactions in the NW Mediterranean: Results from a 30-year 3D modeling study, Prog. Oceanogr., 124, 12–27, https://doi.org/10.1016/j.pocean.2014.04.004, 2014.
Bentsen, M., Evensen, G., Drange, H., Jenkins, A. D.: Coordinate transformation on a sphere using conformal mapping. Mon. Weather Rev., 127, 2733–2740, 1999.
Bernardello, R., Cardoso, J. G., Bahamon, N., Donis, D., Marinov, I., and Cruzado, A.: Factors controlling interannual variability of vertical organic matter export and phytoplankton bloom dynamics – a numerical case-study for the NW Mediterranean Sea, Biogeosciences, 9, 4233–4245, https://doi.org/10.5194/bg-9-4233-2012, 2012.
Béthoux, J. P., Durrieu de Madron, X., Nyffeler, F., and Tailliez, D.: Deep water in the western Mediterranean: peculiar 1999 and 2000 characteristics, shelf formation hypothesis, variability since 1970 and geochemical inferences, J. Mar. Syst., 33-34, 117–131, https://doi.org/10.1016/S0924-7963(02)00055-6, 2002.
Beuvier, J., Béranger, K., Brossier, C. L., Somot, S., Sevault, F., Drillet, Y., Lyard, F.: Spreading of the Western Mediterranean deep water after winter 2005: Time scales and deep cyclone transport, J. Geophys. Res., 117, C07022, https://doi.org/10.1029/2011JC007679, 2012.
Breitburg, D., L.A. Levin, A. Oschlies, M. Grégoire, F.P. Chavez, D.J. Conley, V. Garçon, D.Gilbert, D. Gutiérrez, K. Isensee, et al.:Declining oxygen in the global ocean and coastal waters, Science, 359, eaam7240, 2018.
Breitburg, D. L., D. W. Hondorp, L. A. Davias, R. J. Diaz: Hypoxia, nitrogen, and fisheries: Integrating effects across local and global landscapes. Annu. Rev. Mar. Sci. 1, 329–349, 21141040, 2009.
Bristow, L. A., et al.: 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.
Brodeau, L., Koenigk, T.: Extinction of the northern oceanic deep convection in an ensemble of climate model simulations of the 20th and 21st centuries, Clim. Dyn., 46, 2863–2882, https://doi.org/10.1007/s00382-015-2736-5, 2016.
Bushinsky, S. M. and Emerson, S. R.: Biological and physical controls on the oxygen cycle in the Kuroshio Extension from an array of profiling floats, Deep Sea Res. Part I Oceanogr. Res. Pap., 141, 51–70, ISSN 0967-0637, https://doi.org/10.1016/j.dsr.2018.09.005, 2018.
Bopp, L., Le Quéré, C., Heimann, M., Manning, A. C., and Monfray, P.: Climate-induced oceanic oxygen fluxes: implications for the contemporary carbon budget, Global Biogeochem. Cy., 16, 1022, https://doi.org/10.1029/2001GB001445, 2002.
Canals, M., Puig, P., de Madron, X. et al. Flushing submarine canyons, Nature 444, 354–357, https://doi.org/10.1038/nature05271, 2006.
Conan, P.: DEWEX-MERMEX 2013 LEG2 cruise, RV Le Suroît, SISMER, Brest, France, https://doi.org/10.17600/13020030, 2013.
Conan, P., Testor, P., Estournel, C., D'Ortenzio, F., Pujo-Pay, M., Durrieu de Madron, X.: Preface to the Special Section: Dense water formations in the northwestern Mediterranean: From the physical forcings to the biogeochemical consequences. J. Geophys. Res. Oceans, 123, 6983–6995, https://doi.org/10.1029/2018JC014301, 2018.
Copin-Montégut, C.: Consumption and production on scales of a few days of inorganic carbon, nitrate and oxygen by the planktonic community: results of continuous measurements at the Dyfamed Station in the northwestern Mediterranean Sea (May 1995). Deep Sea Res. Part I, 47, 447–477, https://doi.org/10.1016/S0967-0637(99)00098-9, 2000.
Copin-Montégut, C., Bégovic, M.: Distributions of carbonate properties and oxygen along the water column (0–2000 m) in the central part of the NW Mediterranean Sea (Dyfamed site): influence of winter vertical mixing on air–sea CO2 and O2 exchanges. Deep Sea Res. Part II, 49, 2049–2066, https://doi.org/10.1016/S0967-0645(02)00027-9, 2002.
Copin-Montégut, C., Bégovic, M., Merlivat, L.: Variability of the partial pressure of CO2 on diel to annual time scales in the Northwestern Mediterranean Sea, Mar. Chem., 85, 3–4, 169-189, https://doi.org/10.1016/j.marchem.2003.10.005, 2004.
Coppola, L., Prieur, L., Taupier-Letage, I., Estournel, C., Testor, P., Lefevre, D., Belamari, S., LeReste, S., Taillandier, V.:. Observation of oxygen ventilation into deep waters through targeted deployment of multiple Argo-O2 floats in the north-western Mediterranean Sea in 2013, J. Geophys. Res. Oceans, 122, 6325–6341, https://doi.org/10.1002/2016JC012594, 2017.
Coppola, L., Legendre, L., Lefevre, D., Prieur L., Taillandier V., Diamond Riquiera, E.: Seasonal and inter-annual variations of dissolved oxygen in the northwestern Mediterranean Sea (DYFAMED site). Prog. Oceanogr., 162, 187–201, https://doi.org/10.1016/j.pocean.2018.03.001, 2018.
Diaz, R. J., Rosenberg, R.: Spreading dead zones and consequences for marine ecosystems, Science, 321, 926–929, 18703733, https://doi.org/10.1126/science.1156401, 2008.
D'Ortenzio, F., D. Antoine and S. Marullo: Satellite-driven modelling of the upper ocean mixed layer and air-sea CO2 flux in the Mediterranean Sea, Deep-Sea Res. I, 55, 405–434, https://doi.org/10.1016/j.dsr.2007.12.008, 2008.
Dugenne, M. :Dynamique du phytoplancton en mer Méditerranée: Approches par mesures à haute fréquence, modélisation, et statistiques bayésiennes, PhD Thesis, Aix Marseille Université, available at: http://www.theses.fr/s137171 (last access: 15 April 2020), 2017.
Estournel, C., Durrieu de Madron, X., Marsaleix, P., Auclair, F., Julliand, C., and Vehil, R.: Observation and modeling of the winter coastal oceanic circulation in the Gulf of Lion under wind conditions influenced by the continental orography (FETCH experiment), J. Geophys. Res., 108, 8059, https://doi.org/10.1029/2001JC000825, C3, 2003.
Estournel, C., Testor, P., Damien, P., D’Ortenzio, F., Marsaleix, P.,
Conan, P., Kessouri, F., Durrieu de Madron, X., Coppola L., Lellouche, J.-M., Belamari, S., Mortier, L., Ulses, C., Bouin, M.-N., and Prieur, L.: High resolution modeling of dense water formation in the north-western Mediterranean during winter 2012–2013: Processes and budget, J. Geophys. Res. Oceans, 121, 5367–5392, https://doi.org/10.1002/2016JC011935, 2016a.
Estournel, C., P. Testor, I. Taupier-Letage, M.-N. Bouin, L. Coppola, P. Durand, P. Conan, A. Bosse, P.-E. Brilouet, L. Beguery, S. Belamari, K. Béranger, J. Beuvier, D. Bourras, G. Canut, A. Doerenbecher, X. Durrieu de Madron, F. D'Ortenzio, P. Drobinski, V. Ducrocq, N. Fourrié, H. Giordani, L. Houpert, L. Labatut, C.L. Brossier, M. Nuret, L. Prieur, O. Roussot, L. Seyfried, and S. Somot: HyMeX-SOP2: The field campaign dedicated to dense water formation in the northwestern Mediterranean. Oceanography 29(4):196–206, https://doi.org/10.5670/oceanog.2016.94, 2016b.
Estournel, C., Zervakis, V., Marsaleix, P., Papadopoulos, A., Auclair, F., Perivoliotis, L., Tragou, E.: Dense water formation and cascading in the Gulf of Thermaikos (North Aegean) from observations and modelling, Cont. Shelf Res., 25, 2366–2386, 2005.
Fröb, F., A. Olsen, K. Vage, G. W. Moore, I. Yashayaev, E. Jeansson, and B. Rajasakaren: Irminger Sea deep convection injects oxygen and anthropogenic carbon to the ocean interior, Nat. Commun., 7, 13244, https://doi.org/10.1038/ncomms13244, 2016.
Garcia, Herncin E., Gordon, Louis I.: Oxygen solubility in seawater: Better fitting equations, Limnol. Oceanogr., 37, 1307–1312, https://doi.org/10.4319/lo.1992.37.6.1307, 1992.
Gaspar, P., Y. Gregoris, and J. M. Lefevre, A simple eddy kinetic energy model for simulations of the oceanic vertical mixing: Tests at station Papa and long-term upper ocean study site, J. Geophys. Res., 95, C9, 16179-16193, 1990.
Giorgi, F.: Climate change hot-spots, Geophys. Res. Lett. 33, L08707, https://doi.org/10.1029/2006GL025734, 2006.
Grégoire, M., C. Raick, K. Soetaert: Numerical modeling of the central Black Sea ecosystem functioning during the eutrophication phase, Prog. Oceanogr., 76, 3, 286–333, ISSN 0079-6611, https://doi.org/10.1016/j.pocean.2008.01.002, 2008.
Helm, K. P., Bindoff, N. L. Church, J. A.: Observed decreases in oxygen content of the global ocean. Geophys. Res. Lett. 38, L23602, https://doi.org/10.1029/2011GL049513, 2011.
Herrmann, M., Somot, S., Sevault, F., Estournel, C., Déqué, M. : Modeling the deep convection in the Northwestern Mediterranean sea using an eddy-permitting and an eddy-resolving model: Case study of winter 1986–87. J. Geophy. Res., 113, C04011, https://doi.org/10.1029/2006JC003991, 2008.
Herrmann, M., Auger, P.-A., Ulses, C., and Estournel, C.: Long-term monitoring of ocean deep convection using multisensors altimetry and ocean color satellite data, J. Geophys. Res. Oceans, 122, 1457– 1475, https://doi.org/10.1002/2016JC011833, 2017.
Ho, D.T., Law, C.S., Smith, M.J., Schlosser, P., Harvey, M., Hill, P.: Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: implications for global parameterizations. Geophys. Res. Lett., 33, L16611, https://doi.org/10.1029/2006GL026817, 2006.
Houpert, L., et al.: Observations of open-ocean deep convection in the northwestern Mediterranean Sea: Seasonal and interannual variability of mixing and deep water masses for the 2007–2013 Period, J. Geophys. Res. Oceans, 121, 8139–8171, https://doi.org/10.1002/2016JC011857, 2016.
Huertas, I. E., Ríos, A. F., García-Lafuente, J., Makaoui, A., Rodríguez-Gálvez, S., Sánchez-Román, A., Orbi, A., Ruíz, J., and Pérez, F. F.: Anthropogenic and natural CO2 exchange through the Strait of Gibraltar, Biogeosciences, 6, 647–662, https://doi.org/10.5194/bg-6-647-2009, 2009.
Ito, T., Minobe, S., Long, M. C., and Deutsch, C.: Upper ocean O2 trends: 1958–2015, Geophys. Res. Lett., 44, 4214–4223, https://doi.org/10.1002/2017GL073613, 2017.
Joos, F., G. K. Plattner, T. F. Stocker, A. Kortzinger, and D. W. R. Wallace: Trends in marine dissolved oxygen: Implications for ocean circulation changes and the carbon budget, Eos Trans. AGU, 84(21), 197, https://doi.org/10.1029/2003EO210001, 2003.
Keeling, R. F., and H. Garcia: The change in oceanic O2 inventory associated with recent global warming, Proc. Natl. Acad. Sci. USA, 99, 7848–7853, https://doi.org/10.1073/pnas.122154899, 2002.
Keeling, R. F., Körtzinger, A., and Gruber, N.: Ocean deoxygenation in a warming world, Annu. Rev. Marin. Sci., 2, 199–229, https://doi.org/10.1146/annurev.marine.010908.163855, 2010.
Keraghel M.A., Louanchi F., Zerrouki M., Aït Kaci M., Aït-Ameur N., Labaste M., Legoff H., Taillandier V., Harid R., Mortier L.: Carbonate system properties and anthropogenic carbon inventory in the Algerian Basin during SOMBA cruise (2014): Acidification estimate. Mar. Chem., 221, 103783, https://doi.org/10.1016/j.marchem.2020.103783, 2020.
Kessouri, F., Ulses, C., Estournel, C., Marsaleix, P., Severin, T., Pujo-Pay, M., et al.: Nitrogen and phosphorus budgets in the Northwestern Mediterranean deep convection region, J. Geophys. Res. Oceans, 122, 9429–9454. https://doi.org/10.1002/2016JC012665, 2017.
Kessouri, F., Ulses, C., Estournel, C., Marsaleix, P., D'Ortenzio, F., Severin, T., et al.: Vertical mixing effects on phytoplankton dynamics and organic carbon export in the western Mediterranean Sea. J. Geophys. Res. Oceans, 123, 1647–1669. https://doi.org/10.1002/2016JC012669, 2018.
Killworth, P.: The mixing and spreading phases of MEDOC. I, Prog. Oceanogr., 7, 59–90, https://doi.org/10.1016/0079-6611(76)90005-7, 1976.
Koelling, J., D. W. R. Wallace, U. Send, and J. Karstensen: Intense oceanic uptake of oxygen during 2014–2015 winter convection in the Labrador Sea, Geophys. Res. Lett., 44, 7855–7864, https://doi.org/10.1002/2017GL073933, 2017.
Körtzinger, A., Schimanski, J., Send, U., Wallace, D.: The ocean takes a deep breath, Science, 306, 1337, https://doi.org/10.1126/science.1102557, 2004.
Körtzinger, A., U. Send, R. S. Lampitt, S. Hartman, D. W. R. Wallace, J. Karstensen, M. G. Villagarcia, O. Llinaìs, and M. D. DeGrandpre: The seasonal pCO2 cycle at 49∘ N/16.5∘ W in the northeastern Atlantic Ocean and what it tells us about biological productivity, J. Geophys. Res., 113, C04020, https://doi.org/10.1029/2007JC004347, 2008a.
Körtzinger, A., Send, U., Wallace, D. W. R., Kartensen, J., DeGrandpre, M.: Seasonal cycle of O2 and pCO2 in the central Labrador Sea: Atmospheric, biological, and physical implications. Global Biogeochem. Cycles, 22, GB1014. https://doi.org/10.1029/2007GB003029, 2008b.
Large, W. G., Yeager, S. G.: Diurnal to decadal global forcing for ocean and sea-ice models: The data sets and flux climatologies (NCAR Tech. Note NCAR/TN-4601STR). Boulder, CO: National Center of Atmospheric Research. https://doi.org/10.5065/D6KK98Q6, 2004.
Lavigne, H., D'Ortenzio, F., Migon, C., Claustre, H., Testor, P., Ribera d'Alcala, M., et al. : Enhancing the comprehension of mixed layer depth control on the Mediterranean phytoplankton phenology. J. Geophys. Res. Oceans, 118, 3416–3430. https://doi.org/10.1002/jgrc.20251, 2013.
Lellouche, J.-M., Le Galloudec, O., Drévillon, M., Régnier, C., Greiner, E., Garric, G., Ferry, N., Desportes, C., Testut, C.-E., Bricaud, C., Bourdallé-Badie, R., Tranchant, B., Benkiran, M., Drillet, Y., Daudin, A., and De Nicola, C.: Evaluation of global monitoring and forecasting systems at Mercator Océan, Ocean Sci., 9, 57–81, https://doi.org/10.5194/os-9-57-2013, 2013.
Levin, L.: Oxygen minimum zone benthos: Adaptation and community response to hypoxia, Oceanogr. Mar. Biol. 41, 1–45, 2003.
Li, P., and Tanhua, T.: Recent Changes in Deep Ventilation of the Mediterranean Sea; Evidence From Long-Term Transient Tracer Observations, Front. Mar. Sci., 7, https://doi.org/10.3389/fmars.2020.00594, 2020.
Liang, J.-H., Deutsch, C., McWilliams, J. C., Baschek, B., Sullivan, P. P., Chiba, D.: Parameterizing bubble-mediated air-sea gas exchange and its effect on ocean ventilation. Global Biogeochem. Cycles, 27, 894–905, https://doi.org/10.1002/gbc.20080, 2013.
Lopez-Jurado, J.-L., C. Gonzalez-Pola, and P. Velez-Belchi: Observation of an abrupt disruption of the long-term warming trend at the Balearic Sea, western Mediterranean Sea, in summer 2005, Geophys. Res. Lett., 32, L24606, https://doi.org/10.1029/2005GL024430, 2005.
Ludwig, W., Bouwman, A. F., Dumont, E., Lespinas, F.: Water and nutrient fluxes from major Mediterranean and Black Sea rivers: Past and future trends and their implications for the basin-scale budgets. Global Biogeochem. Cycles, 24, GB0A13. https://doi.org/10.1029/2009GB003594, 2010.
Manca, M., Burca, M., Giorgetti, A., Coatanoan, C., Garcia, M. J., Iona, A.: Physical and biochemical averaged vertical profiles in the Mediterranean regions: An important tool to trace the climatology of water masses and to validate incoming data from operational oceanography. J. Mar. Syst., 48(1–4), 83–116, 2004.
Mavropoulou, A.-M., Vervatis, V., and Sofianos, S.: Dissolved oxygen variability in the Mediterranean Sea, J. Mar. Syst., 208, https://doi.org/10.1016/j.jmarsys.2020.103348, 2020.
Maze, G., Mercier, H., Thierry, V., Memery, L., Morin, P., and Perez, F. F.: Mass, nutrient and oxygen budgets for the northeastern Atlantic Ocean, Biogeosciences, 9, 4099–4113, https://doi.org/10.5194/bg-9-4099-2012, 2012.
MEDOC-Group: Observations of formation of deep-water in the Mediterranean Sea, Nature, 227, 1037–1040, 1970.
Merlivat, L., Boutin, J., Antoine, D., Beaumont, L., Golbol, M., and Vellucci, V.: Increase of dissolved inorganic carbon and decrease in pH in near-surface waters in the Mediterranean Sea during the past two decades, Biogeosciences, 15, 5653–5662, https://doi.org/10.5194/bg-15-5653-2018, 2018.
Mertens, C. and Schott F.: Interannual variability of deep-water formation in the northwestern Mediterranean, J. Phys. Oceanogr., 28, 1410–1424, https://doi.org/10.1175/1520-0485(1998)028<1410:IVODWF>2.0.CO;2, 1998.
Minas, H.J. and Bonin, M.-C. : Oxygénation physique et biologique de la Méditerranée nord-occidentale en hiver et au printemps. Oceanol. Acta (Special Issue No. 9), 123–132, 1988.
Moutin, T., Raimbault, P., Golterman, H. L., and Coste, B.: The input of nutrients by the Rhône River into the Mediterranean Sea: Recent observations and comparison with earlier data. Hydrobiologia, 373, 237, https://doi.org/10.1023/A:1017020818701, 1998.
Naqvi, S. W. A., Bange, H. W., Farías, L., Monteiro, P. M. S., Scranton, M. I., and Zhang, J.: Marine hypoxia/anoxia as a source of CH4 and N2O, Biogeosciences, 7, 2159–2190, https://doi.org/10.5194/bg-7-2159-2010, 2010.
Nightingale PD, Malin G, Law CS, Watson AJ, Liss PS, et al.: In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers, Glob. Biogeochem. Cycles, 14, 373–387, https://doi.org/10.1029/1999GB900091, 2000.
Palevsky, H. I., Quay, P. D., Lockwood, D. E., and Nicholson, D. P.: The annual cycle of gross primary production, net community production, and export efficiency across the North Pacific Ocean, Global Biogeochem. Cycles, 30, 361–380, https://doi.org/10.1002/2015GB005318, 2016.
Pastor, L., Cathalot, C., Deflandre, B., Viollier, E., Soetaert, K., Meysman, F. J. R., Ulses, C., Metzger, E., and Rabouille, C.: Modeling biogeochemical processes in sediments from the Rhône River prodelta area (NW Mediterranean Sea), Biogeosciences, 8, 1351–1366, https://doi.org/10.5194/bg-8-1351-2011, 2011.
Piñeiro, S., González Pola, C., Fernández Díaz, J. M., and Balbin, R.: Thermohaline evolution of the Western Mediterranean deep waters since 2005: Diffusive stages and interannual renewal injections. J. Geophys. Res. Oceans, 124, 8747–8766, https://doi.org/10.1029/2019JC015094, 2019.
Pinot, J.M. and Ganachaud, A.: The role of winter intermediate waters in the spring-summer circulation of the Balearic Sea: 1. Hydrography and inverse box modeling, J. Geophys. Res., 104(C12), 29843–29864, https://doi.org/10.1029/1999JC900202, 1999.
Plattner, G.-K. and Joos, E., Stocker, T. E.: Revision of the global carbon budget due to changing air-sea oxygen fluxes, Global Biogeochem. Cycles, 16, 1096, https://doi.org/10.1029/2001GB001746, 2002.
Rhein, M.: Deep water formation in the western Mediterranean, J. Geophys. Res., 100(C4), 6943, https://doi.org/10.1029/94JC03198, 1995.
Santinelli, C., Nannicini, L., Seritti, A.: DOC dynamics in the meso and bathypelagic layers of the Mediterranean Sea, Deep Sea Res. Part II, 57, 1446–1459, 2010.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic oxygen content during the past five decades. Nature 542, 335–339, https://doi.org/10.1038/nature21399, 2017.
Schneider, A., Tanhua, T., Roether, W., and Steinfeldt, R.: Changes in ventilation of the Mediterranean Sea during the past 25 year, Ocean Sci., 10, 1–16, https://doi.org/10.5194/os-10-1-2014, 2014.
Scholz, F., McManus, J., Mix, A. C. , Hensen, C., Schneider, R. R.: The impact of ocean deoxygenation on iron release from continental margin sediments. Nat. Geosci. 7, 433–437, https://doi.org/10.1038/ngeo2162, 2014.
Schott F, Visbeck, M., Send, U., Fischer, J., Stramma, L., and Desaubies, Y.: Observations of deep convection in the Gulf of Lion, Northern Mediterranean, during the winter of 1991/1992, J. Phys. Oceanogr., 26, 505–524, https://doi.org/10.1175/1520-0485(1996)026<0505:OODCIT>2.0.CO;2, 1996.
Schroeder, K., Gasparini, G. P., Tangherlini, M., and Astraldi, M.: Deep and intermediate water in the western Mediterranean under the influence of the Eastern Mediterranean Transient, Geophys. Res. Lett., 33, L21607, https://doi.org/10.1029/2006GL027121, 2006.
Schroeder, K., Ribotti, A., Borghini, M., Sorgente, R., Perilli, A., Gasparini, G. P.: An extensive Mediterranean deep water renewal between 2004 and 2006. Geophys. Res. Lett., 35, L18605, https://doi.org/10.1029/2008GL035146, 2008a.
Schroeder, K., Taillandier, V., Vetrano, A., and Gasparini, G.P.: The circulation of the western Mediterranean Sea in spring 2005 as inferred from observations and from model outputs, Deep Sea Res. Part I Oceanogr. Res. Pap., 55, 8 947–965, ISSN 0967-0637, https://doi.org/10.1016/j.dsr.2008.04.003, 2008b.
Sempéré, R., Charrière, B., Van Wambeke, F., Cauwet, G.: Carbon inputs of the Rhône River to the Mediterranean Sea: Biogeochemical Implications. Global Biogeochem. Cycles, 14, 669–681, https://doi.org/10.1029/1999GB900069, 2000.
Soetaert, K., Herman, P. M. J., Middelburg, J. J., Heip, C., Smith, C. L., Tett, P., and Wild-Allen, K.: Numerical modelling of the shelf break ecosystem: Reproducing benthic and pelagic measurements, Deep Sea Res. Part II Top. Stud. Oceanogr., 48, 3141–3177, 2001.
Somot, S., Houpert, L., Sevault, F., Testor, P., Bosse, A., Taupier-Letage, I., Bouin, M.-N., Waldman, R., Cassou, C., Sanchez-Gomez, E., Durrieu de Madron, X., Adloff, F., Nabat, P., and Herrmann, M.: Characterizing, modelling and understanding the climate variability of the deep water formation in the North-Western Mediterranean Sea, Clim. Dyn., 51, 1179–1210, https://doi.org/10.1007/s00382-016-3295-0, 2016.
Soto-Navarro, J., Jordá, G., Amores, A., Cabos, W., Somot, S., Sevault, F., Macías, D., Djurdjevic, V., Sannino, G., Li, L., and Sein, D.: Evolution of Mediterranean Sea water properties under climate change scenarios in the Med-CORDEX ensemble, Clim. Dyn., 54, 2135–2165, https://doi.org/10.1007/s00382-019-05105-4, 2020.
Stanley, R. H. R., Jenkins, W. J., Lott, D. E., and Doney, S. C.: Noble gas constraints on air-sea gas exchange and bubble fluxes, J. Geophys. Res., 114, C11020, https://doi.org/10.1029/2009JC005396, 2009.
Stöven, T. and Tanhua, T.: Ventilation of the Mediterranean Sea constrained by multiple transient tracer measurements, Ocean Sci., 10, 439–457, https://doi.org/10.5194/os-10-439-2014, 2014.
Stramma, L., Schmidtko, S., Levin, L. A., Johnson, G. C.: Ocean oxygen minima expansions and their biological impacts. Deep-Sea Res. Part I, 57, 587–595, https://doi.org/10.1016/j.dsr.2010.01.005, 2010.
Tanhua, T., Hainbucher, D., Schroeder, K., Cardin, V., Álvarez, M., and Civitarese, G.: The Mediterranean Sea system: a review and an introduction to the special issue, Ocean Sci., 9, 789–803, https://doi.org/10.5194/os-9-789-2013, 2013.
Testor, P.: DEWEX-MERMEX 2013 LEG1 cruise, RV Le Suroît, SISMER, Brest, France, https://doi.org/10.17600/13020010, 2013.
Testor, P., Bosse, A., Houpert, L., Margirier, F., Mortier, L., Legoff, H., Dausse, D., Labaste, M., Karstensen, J., Hayes, D., Olita, A., Ribotti, A., Schroeder, K., Chiggiato, J., Onken, R., Heslop, E., Mourre, B., D'ortenzio, F., Mayot, N., Lavigne, H., de Fommervault O., Coppola, L., Prieur, L., Taillandier, V., Durrieu de Madron, X., Bourrin , F., Many, G., Damien, P., Estournel, C., Marsaleix, P., Taupier-Letage, I., Raimbault, P., Waldman, R., Bouin, M.N., Giordani, H., Caniaux, G., Somot, S., Ducrocq, V., and P. Conan: Multiscale observations of deep convection in the northwestern Mediterranean Sea during winter 2012–2013 using multiple platforms. J. Geophys. Res. Oceans, 123, https://doi.org/10.1002/2016JC012671, 2018.
Testor, P., Coppola, L., and Mortier, L.: MOOSE-GE 2013 cruise, RV Téthys II, SISMER, Brest, France, https://doi.org/10.17600/13450110, 2013.
Touratier, F., Goyet, C., Houpert, L., de Madron, X.D., Lefèvre, D., Stabholz, M., and Guglielmi, V.: Role of deep convection on anthropogenic CO2 sequestration in the Gulf of Lions (northwestern Mediterranean Sea), Deep Sea Res. Part I, 113, 33–48, https://doi.org/10.1016/j.dsr.2016.04.003, 2016.
Ulses, C., Auger, P.-A., Soetaert, K., Marsaleix, P., Diaz, F., Coppola, L., Herrmann, M., Kessouri, F., and Estournel, C.: Budget of organic carbon in the North-Western Mediterranean Open Sea over the period 2004–2008 using 3D coupled physical biogeochemical modeling. J. Geophys. Res. Oceans, 121, 7026–7055, https://doi.org/10.1002/2016JC011818, 2016.
Ulses, C., Estournel, C., Fourrier, M., Coppola, L., Kessouri, F., Lefèvre, D.,
and Marsaleix, P.: Modelling the dissolved oxygen dynamics in the north-western Mediterranean deep-convection region during the year 2012/13, [Data set], available on request from the corresponding author, last access: 13 October 2020.
Ulses, C., C. Estournel, J. Bonnin, X. Durrieu de Madron, and P. Marsaleix: Impact of storms and dense water cascading on shelf-slope exchanges in the Gulf of Lion (NW Mediterranean), J. Geophys. Res., 113, C02010, https://doi.org/10.1029/2006JC003795, 2008a.
Ulses, C., C. Estournel, P. Puig, X. Durrieu de Madron, and P. Marsaleix: Dense shelf water cascading in the northwestern Mediterranean during the cold winter 2005. Quantification of the export through the Gulf of Lion and the Catalan margin. Geophys. Res. Lett., 35, L07610, https://doi.org/10.1029/2008GL033257, 2008b.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean. J. Geophys. Res., 97, 7373–7382, https://doi.org/10.1029/92JC00188, 1992.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean revisited, Limnol. Oceanogr. Methods, 12, https://doi.org/10.4319/lom.2014.12.351, 2014.
Wanninkhof, R., Asher, W. E., Ho, D. T., Sweeney, C., and McGillis, W. R.: Advances in quantifying air-sea gas exchange and environmental forcing, Annu. Rev. Mar. Sci., 1, 213–244, https://doi.org/10.1146/annurev.marine.010908.163742, 2009.
Wanninkhof, R. and McGillis, W. R.: A cubic relationship between gas transfer and wind speed. Geophys. Res. Lett., 26, 1889–1893, 1999.
Wolf, M. K., Hamme, R. C., Gilbert, D., Yashayaev, I., Thierry, V.: Oxygen saturation surrounding Deep Water formation events in the Labrador Sea from Argo-O2 data, Global Biogeochem. Cycles, 32, 635–653, https://doi.org/10.1002/2017GB005829, 2018.
Woolf, D. K.: Bubbles and their role in gas exchange, in The Sea Surface and Global Change, edited by P. S. Liss and R. A. Duce, 173–206, Cambridge Univ. Press, Cambridge, U.K., https://doi.org/10.1017/CBO9780511525025.007, 1997.
Yang, B., Emerson, S. R., Bushinsky, S. M.: Annual net community production in the subtropical Pacific Ocean from in situ oxygen measurements on profiling floats, Global Biogeochem. Cycles, 31, 728–744, https://doi.org/10.1002/2016GB005545, 2017.
Zunino, P., Schroeder, K., Vargas-Yáñez, M., Gasparini, G.P., Coppola, L., García-Martínez, M.C., Moya-Ruiz, F.: Effects of the Western Mediterranean Transition on the resident water masses: Pure warming, pure freshening and pure heaving, J. Mar. Syst., 96, 15–23, https://doi.org/10.1016/j.jmarsys.2012.01.011, 2012.
Short summary
We analyse the seasonal cycle of O2 and estimate an annual O2 budget in the north-western Mediterranean deep-convection region, using a numerical model. We show that this region acts as a large sink of atmospheric O2 and as a major source of O2 for the western Mediterranean Sea. The decrease in the deep convection intensity predicted in recent projections may have important consequences on the overall uptake of O2 in the Mediterranean Sea and on the O2 exchanges with the Atlantic Ocean.
We analyse the seasonal cycle of O2 and estimate an annual O2 budget in the north-western...
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