Articles | Volume 15, issue 21
https://doi.org/10.5194/bg-15-6461-2018
© Author(s) 2018. 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-15-6461-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
02 Nov 2018
Research article |
| 02 Nov 2018
| 02 Nov 2018
Evaluation of the seasonal formation of subsurface negative preformed nitrate anomalies in the subtropical North Pacific and North Atlantic
Robert T. Letscher
CORRESPONDING AUTHOR
Earth Sciences and Ocean Process Analysis Laboratory, University of New
Hampshire, Durham, NH 03824, USA
Tracy A. Villareal
Department of Marine Science and Marine Science Institute, The University
of Texas at Austin, Port Aransas, Austin, TX 78382, USA
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Kieran Curran, Tracy A. Villareal, and Robert T. Letscher
Biogeosciences, 22, 3515–3531, https://doi.org/10.5194/bg-22-3515-2025, https://doi.org/10.5194/bg-22-3515-2025, 2025
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This work provides a 2-year record of marine organic gel concentrations from an open-ocean site in the subtropical North Pacific Ocean north of Hawaii. These microscopic gels are investigated to understand their importance as an understudied component of organic matter cycling by marine microbes. We find an important role of gel cycling during the summer months, helping explain previously contradictory estimates of nutrient supply and demand for the subtropical ocean.
R. T. Letscher, J. K. Moore, Y.-C. Teng, and F. Primeau
Biogeosciences, 12, 209–221, https://doi.org/10.5194/bg-12-209-2015, https://doi.org/10.5194/bg-12-209-2015, 2015
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Marine DOM is known to exhibit stoichiometry depleted in N and P compared with POM, suggesting variable production and remineralization stoichiometry for C, N, and P within marine DOM cycling. We utilize marine DOM observations and an inverse tracer modeling framework to optimize DOM cycling parameters for the BEC biogeochemistry ocean model of the CESM, finding a variable stoichiometry with faster turnover of P > N > C superior to the commonly assumed Redfield stoichiometry for marine DOM.
Kieran Curran, Tracy A. Villareal, and Robert T. Letscher
Biogeosciences, 22, 3515–3531, https://doi.org/10.5194/bg-22-3515-2025, https://doi.org/10.5194/bg-22-3515-2025, 2025
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This work provides a 2-year record of marine organic gel concentrations from an open-ocean site in the subtropical North Pacific Ocean north of Hawaii. These microscopic gels are investigated to understand their importance as an understudied component of organic matter cycling by marine microbes. We find an important role of gel cycling during the summer months, helping explain previously contradictory estimates of nutrient supply and demand for the subtropical ocean.
Nicole J. Bale, Tracy A. Villareal, Ellen C. Hopmans, Corina P. D. Brussaard, Marc Besseling, Denise Dorhout, Jaap S. Sinninghe Damsté, and Stefan Schouten
Biogeosciences, 15, 1229–1241, https://doi.org/10.5194/bg-15-1229-2018, https://doi.org/10.5194/bg-15-1229-2018, 2018
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Associations between diatoms and N-fixing cyanobacteria (diatom–diazotroph associations, DDAs) play an important role in the N cycle of the tropical North Atlantic. Heterocysts are the site of N fixation and contain unique glycolipids. We measured these glycolipids in the water column and surface sediment from the tropical North Atlantic. We found a significant correlation between the concentration of glycolipid and of DDAs, strengthening their application as biomarkers.
R. T. Letscher, J. K. Moore, Y.-C. Teng, and F. Primeau
Biogeosciences, 12, 209–221, https://doi.org/10.5194/bg-12-209-2015, https://doi.org/10.5194/bg-12-209-2015, 2015
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Marine DOM is known to exhibit stoichiometry depleted in N and P compared with POM, suggesting variable production and remineralization stoichiometry for C, N, and P within marine DOM cycling. We utilize marine DOM observations and an inverse tracer modeling framework to optimize DOM cycling parameters for the BEC biogeochemistry ocean model of the CESM, finding a variable stoichiometry with faster turnover of P > N > C superior to the commonly assumed Redfield stoichiometry for marine DOM.
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This work provides a 2-year record of marine organic gel concentrations from an open-ocean site in the subtropical North Pacific Ocean north of Hawaii. These microscopic gels are investigated to understand their importance as an understudied component of organic matter cycling by marine microbes. We find an important role of gel cycling during the summer months, helping explain previously contradictory estimates of nutrient supply and demand for the subtropical ocean.
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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
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Jens Terhaar
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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.
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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.
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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
Abell, J., Emerson, S., and Renaud, P.: Distributions of TOP, TON and TOC in
the North Pacific subtropical gyre: Implications for nutrient supply in the
surface ocean and remineralization in the upper thermocline, J. Marine
Research, 58, 203–222, 2000.
Abell, J., Emerson, S., and Keil, R. G.: Using preformed nitrate to infer
decadal changes in DOM remineralization in the subtropical North Pacific,
Global Biogeochem. Cy., 19, GB1008, https://doi.org/10.1029/2004GB002285, 2005.
Ascani, F., Richards, K. J., Firing, E., Grant, S., Johnson, K. S., Jia, Y.,
Lukas, R., and Karl, D. M.: Physical and biological controls of nitrate
concentrations in the upper subtropical North Pacific Ocean, Deep-Sea Res.
Pt. II, 93, 119–134, 2013.
Alldredge, A. L. and Silver, M. W.: Abundance and production rates of
floating diatom mats (Rhizosolenia castracanei and
Rhizosolenia imbricata var. shrubsolei) in the eastern
Pacific Ocean, Mar. Biol., 66, 83–88, 1982.
Alldredge, A. L., Passow, U., and Logan, B. E.: The abundance and
significance of a class of large, transparent organic particles in the ocean,
Deep-Sea Res. Pt. I, 40, 1131–1140, 1993.
Ammerman, J. W., Hood, R. R., Case, D. A., and Cotner, J. B.: Phosphorus
deficiency in the Atlantic: An emerging paradigm in oceanography, Eos T. Am.
Geophys. Un., 84, 165–170, 2003.
Anderson, L. A.: On the hydrogen and oxygen content of marine phytoplankton,
Deep-Sea Res. Pt. 1, 42, 1675–1680, 1995.
Anderson, L. A. and Sarmiento, J. L.: Redfield ratios of remineralization
determined by nutrient data analysis, Global Biogeochem. Cy., 8, 65–80,
1994.
Azetsu-Scott, K. and Passow, U.: Ascending marine particles: Significance of
transparent exopolymer particles (TEP) in the upper ocean, Limnol. Oceanogr.,
49, 741–748, 2004.
Ballek, R. W. and Swift, E.: Nutrient-and light-mediated buoyancy control of
the oceanic non-motile dinoflagellate Pyrocystis noctiluca Murray ex
Haeckel (1890), J. Exp. Mar. Biol. Ecol., 101, 175–192, 1986.
Bauerfeind, E.: Primary production and phytoplankton biomass in the
equatorial region of the Atlantic at 22∘ west, Oceanological Acta,
Proceedings of the International Symposium on Equatorial Vertical Motion,
131–136, 1987.
Belyayeva, T. V.: Range and numbers of diatoms in the genus
Ethmodiscus Castr. in the Pacific plankton and sediments,
Oceanology, Academy of Science, USSR, Eos T. Am. Geophys. Un., 8, 79–85,
1968.
Belyayeva, T. V.: Abundance of Ethmodiscus in Pacific plankton,
Oceanology, Academy of Science, USSR, Eos T. Am. Geophys. Un., 10, 672–675,
1970.
Booth, B. C.: Vernal phytoplankton community in the eastern subarctic
Pacific: Predominant species, Proceedings of the Sixth International Diatom Symposium, edited by: Ross, R., Otto Koeltz, Koenigstein, Germany, 339–358, 1980.
Broecker, W. S.: “NO” A conservative water-mass tracer, Earth Planet. Sc.
Lett., 23, 100–107, 1974.
Carlson, C. A., Ducklow, H. W., and Sleeter, T. D.: Stocks and dynamics of
bacterioplankton in the northwestern Sargasso Sea, Deep-Sea Res. Pt. II, 43,
491–515, 1996.
Caron, D. A., Lim, E. L., Sanders, R. W., Dennett, M. R., and Berninger, U.
G.: Responses of bacterioplankton and phytoplankton to organic carbon and
inorganic nutrient addition in two oceanic ecosystems, Aquat. Microb. Ecol.,
22, 175–184, 2000.
Carpenter, E. J., Harbison, R. G., Madin, L. P., Swanberg, N. R., Biggs, D.
C., Hulburt, E. M., McAlister, V. L., and McCarthy, J. J.:
Rhizosolenia Mats, Limnol. Oceanogr., 22, 739–741, 1977.
Church, M. J., Ducklow, H. W., and Karl, D. M.: Light dependence of [3H]
leucine incorporation in the oligotrophic North Pacific Ocean, Appl. Environ.
Microbiol., 70, 4079–4087, 2004.
Cisternas-Novoa, C., Lee, C., and Engel, A.: Transparent exopolymer particles
(TEP) and Coomassie stainable particles (CSP): Differences between their
origin and vertical distributions in the ocean, Mar. Chem., 175, 56–71,
2015.
Cleve, P.: Seasonal distribution of Atlantic plankton organisms, D. R.
Bonniers, Göteborg, 368 pp., 1900.
Cotner, J. B., Ammerman, J. W., Peele, E. R., and Bentzen, E.:
Phosphorus-limited bacterioplankton growth in the Sargasso Sea, Aquat.
Microb. Ecol., 13, 141–149, 1997.
Cowen, J. P. and Holloway, C. F.: Structural and chemical analysis of marine
aggregates: in-situ macrophotography and laser confocal and electron
microscopy, Mar. Biol., 126, 163–174, 1996.
Cullen, J. J.: Diel vertical migration by dinoflagellates: roles of
carbohydrate metabolism and behavioral flexibility, in: Migration: mechanisms
and adaptive significance, edited by: Rankin, M. A., Marine Science
Institute, Port Aransas, 135–152, 1985.
Darwin, C.: The Voyage of the Beagle, Natural History Library edition (1962),
edited by: Engle, L., Doubleday, New York, 524 pp., 1860.
DeVries, T. and Deutsch, C.: Large-scale variations in the stoichiometry of
marine organic matter respiration, Nat. Geosci., 7, 890–894, 2014.
Doney, S. C. and Bullister, J. L.: A chlorofluorocarbon section in the
eastern North Atlantic, Deep-Sea Res. Pt. I, 39, 1857–1883, 1992.
Emerson, S.: Annual net community production and the biological carbon flux
in the ocean, Global Biogeochem. Cy., 28, 14–28, 2014.
Emerson, S., Quay, P., Karl, D., Winn, C., Tupas, L., and Landry, M.:
Experimental determination of the organic carbon flux from open-ocean surface
waters, Nature, 389, 951–954, 1997.
Engel, A.: Distribution of transparent exopolymer particles (TEP) in the
northeast Atlantic Ocean and their potential significance for aggregation
processes, Deep-Sea Res. Pt. I, 51, 83–92, 2004.
Eppley, R. W., Holm-Hansen, O., and Strickland, J. D. H.: Some observations
on the vertical migration of dinoflagellates, J. Phycol., 4, 333–340, 1968.
Fawcett, S. E., Lomas, M. W., Casey, J. R., Ward, B. B., and Sigman, D. M.:
Assimilation of upwelled nitrate by small eukaryotes in the Sargasso Sea,
Nat. Geosci., 4, 717–722, 2011.
Fraga, F.: Phytoplanktonic biomass synthesis: application to deviations from
Redfield stoichiometry, Sci. Mar., 65, 153–169, 2001.
Fraga, F., Pérez, F. F., Figueiras, F. G., and Rios, A. F.:
Stoichiometric variations of N, P, C and O2 during a
Gymnodinium catenatum red tide and their interpretation, Mar. Ecol.
Prog. Ser., 87, 123–134, 1992.
Fraga, F., Rios, A. F., Pérez, F. F., Estrada, M., and Marrase, C.:
Effect of upwelling pulses on excess carbohydrate synthesis as deduced from
nutrient, carbon dioxide, and oxygen profiles, Mar. Ecol. Prog. Ser., 189,
65–75, 1999.
Ganf, G. G. and Oliver, R. L.: Vertical separation of light and available
nutrients as a factor causing replacement of green algae by blue-green algae
in the plankton of a stratified lake, J. Ecol., 829–844, 1982.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Baranova, O.
K., Zweng, M. M., Reagan, J. R., and Johnson, D. R.: World Ocean Atlas 2013,
in: Dissolved Oxygen, Apparent Oxygen Utilization, and Oxygen Saturation,
vol. 3, edited by: Levitus, S. and Mishonov, A.. NOAA Atlas NESDIS 75,
27 pp., 2014a.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Baranova, O.
K., Zweng, M. M., Reagan, J. R., and Johnson, D. R.: World Ocean Atlas 2013,
in: Dissolved Inorganic Nutrients (phosphate, nitrate, silicate), vol. 4,
edited by: Levitus, S. and Mishonov, A., NOAA Atlas NESDIS 76, 25 pp., 2014b.
Goncalves da Silva, M. G.: Diatom (Bacillariophyceae) distribution in the
continental shelf of Pernambuco (Brazil), Trab. Oceanogr. Univ. Fed.
Pernambuco., 17, 7–46, 1982 (in Spanish).
Gruber, N., Keeling, C. D., and Stocker, T. F.: Carbon-13 constraints on the
seasonal inorganic carbon budget at the BATS site in the northwestern
Sargasso Sea, Deep-Sea Res. Pt. I, 45, 673–717, 1998.
Gruber, N., Keeling, C. D., and Bates, N. R.: Interannual variability in the
North Atlantic Ocean carbon sink, Science, 298, 2374–2378, 2002.
Guidi, L., Calil, P. H. R., Duhamel, S., Bjoerkman, K. M., Doney, S. C.,
Jackson, G. A., Li, B., Church, M. J., Tozzi, S., Kolber, Z. S., Richards, K.
J., Fong, A. A., Letelier, R. M., Gorsky, G., Stemmann, L., and Karl, D. M.:
Does eddy-eddy interaction control surface phytoplankton distribution and
carbon export in the North Pacific Subtropical Gyre?, J. Geophys.
Res.-Biogeosci., 117, G02024, https://doi.org/10.1029/2012jg001984, 2012.
Gundersen, K., Heldal, M., Norland, S., Purdie, D. A., and Knap, A. H.:
Elemental C, N, and P cell content of individual bacteria collected at the
Bermuda Atlantic Time-series Study (BATS) site, Limnol. Oceanogr., 47,
1525–1530, 2002.
Hamanaka, J., Tanoue, E., Hama, T., and Handa, N.: Production and export of
particulate fatty acids, carbohydrates and combined amino acids in the
euphotic zone, Mar. Chem., 77, 55–69, 2002.
Hansell, D. A. and Carlson, C. A.: Biogeochemistry of total organic carbon
and nitrogen in the Sargasso Sea: control by convective overturn, Deep-Sea
Res. Pt. II, 48, 1649–1667, 2001.
Hasle, G. R.: Phototactic vertical migration in marine dinoflagellates,
Oikos, 2, 162–175, 1950.
Jenkins, W. J. and Doney, S. C.: The subtropical nutrient spiral, Global
Biogeochem. Cy., 17, 1110, https://doi.org/10.1029/2003GB002085, 2003.
Jenkins, W. J. and Goldman, J. C.: Seasonal oxygen cycling and primary
production in the Sargasso Sea, J. Mar. Res., 43, 465–491, 1985.
Johnson, K. S., Riser, S. C., and Karl, D. M.: Nitrate supply from deep to
near-surface waters of the North Pacific subtropical gyre, Nature, 465,
1062–1065, 2010.
Joseph, L., Villareal, T. A., and Lipschultz, F.: A high sensitivity nitrate
reductase assay and its application to vertically migrating Rhizosolenia
mats, Aquat. Microb. Ecol., 12, 95–104, 1997.
Kahn, H. and Swift, E.: Positive buoyancy through ionic control in the
nonmotile marine dinoflagellate Pyrocystis noctiluca Murray ex
Schuett, Limnol. Oceanogr., 23, 649–658, 1978.
Keeling, C. D., Brix, H., and Gruber, N.: Seasonal and long-term dynamics of
the upper ocean carbon cycle at Station ALOHA near Hawaii, Global Biogeochem.
Cy., 18, GB4006, https://doi.org/10.1029/2004GB002227, 2004.
Kirchman, D. L.: The uptake of inorganic nutrients by heterotrophic bacteria,
Microb. Ecol., 28, 255–271, 1994.
Letscher, R. T. and Moore, J. K.: Preferential remineralization of dissolved
organic phosphorus and non-Redfield DOM dynamics in the global ocean: Impacts
on marine productivity, nitrogen fixation, and carbon export, Global
Biogeochem. Cy., 29, 325–340, 2015.
Letscher, R. T. and Villareal, T. A: Residual preformed nitrate and
phosphate at Station ALOHA and BATS, PANGAEA,
https://doi.pangaea.de/10.1594/PANGAEA.895472, 2018.
Letscher, R. T., Knapp, A. N., James, A. K., Carlson, C. A., Santoro, A. E.,
and Hansell, D. A.: Microbial community composition and nitrogen availability
influence DOC remineralization in the South Pacific Gyre, Mar. Chem., 177,
325–334, 2015.
Letscher, R. T., Primeau, F., and Moore, J. K.: Nutrient budgets in the
subtropical ocean gyres dominated by lateral transport, Nat. Geosci., 9,
815–819, 2016.
Long, R. A. and Azam, F.: Abundant protein-containing particles in the sea,
Aquat. Microb. Ecol., 10, 213–221, 1996.
Mari, X., Passow, U., Migon, C., Burd, A. B., and Legendre, L.: Transparent
exopolymer particles: Effects on carbon cycling in the ocean, Progr.
Oceanogr., 151, 13–37, 2017.
Martin, J. H., Knauer, G. A., Karl, D. M., and Broenkow, W. W.: VERTEX:
carbon cycling in the northeast Pacific, Deep-Sea Res. Pt. A, 34, 267–285,
1987.
Martinez, L. A.: Nitrogen fixation by floating diatom mats: a source of new
nitrogen to oligotrophic ocean waters, Biology, University of California,
Santa Cruz, 23 pp., 1982.
Martiny, A. C., Pham, C. T., Primeau, F. W., Vrugt, J. A., Moore, J. K.,
Levin, S. A., and Lomas, M. W.: Strong latitudinal patterns in the elemental
ratios of marine plankton and organic matter, Nat. Geosci., 6, 279–283,
2013.
Michaels, A. F., Bates, N. R., Buesseler, K. O., Carlson, C. A., and Knap, A.
H.: Carbon-cycle imbalances in the Sargasso Sea, Nature, 372, 537–540, 1994.
Mikkelsen, N.: On the origin of Ethmodiscus ooze, Mar.
Micropaleontol., 2, 35–46, 10.1016/0377-8398(77)90004-4, 1977.
Moore, J. K. and Villareal, T. A.: Size-ascent rate relationships in
positively buoyant marine diatoms, Limnol. Oceanogr., 41, 1514–1520, 1996.
Moore, J. K., Doney, S. C., and Lindsay, K.: Upper ocean ecosystem dynamics
and iron cycling in a global three-dimensional model, Global Biogeochem. Cy.,
18, GB4028, https://doi.org/10.1029/2004GB002220 , 2004.
Navarro, G. and Ruiz, J.: Hysteresis conditions the vertical position of deep
chlorophyll maximum in the temperate ocean, Global Biogeochem. Cy., 27,
1013–1022, 2013.
Olsen, A., Key, R. M., van Heuven, S., Lauvset, S. K., Velo, A., Lin, X.,
Schirnick, C., Kozyr, A., Tanhua, T., Hoppema, M., Jutterström, S.,
Steinfeldt, R., Jeansson, E., Ishii, M., Pérez, F. F., and Suzuki, T.:
The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally
consistent data product for the world ocean, Earth Syst. Sci. Data, 8,
297–323, https://doi.org/10.5194/essd-8-297-2016, 2016.
Paulmier, A., Kriest, I., and Oschlies, A.: Stoichiometries of
remineralisation and denitrification in global biogeochemical ocean models,
Biogeosciences, 6, 923–935, https://doi.org/10.5194/bg-6-923-2009, 2009.
Pilskaln, C. H., Villareal, T. A., Dennett, M., Darkangelo-Wood, C., and
Meadows, G.: High concentrations of marine snow and diatom algal mats in the
North Pacific Subtropical Gyre: Implications for carbon and nitrogen cycles
in the oligotrophic ocean, Deep-Sea Res. Pt. I, 52, 2315–2332, 2005.
Platt, T., Harrison, W. G., Lewis, M. R., Li, W. K., Sathyendranath, S.,
Smith, R. E., and Vezina, A. F.: Biological production of the oceans: the
case for a consensus, Marine Ecology Progress Series, 77–88, 1989.
Ricard, M.: Observations sur les diatomées marines du genre
Ethmodiscus Castr., Rev. Algol. N.S.O, 10, 56–73, 1970.
Richardson, T. L., Ciotti, A. M., Cullen, J. J., and Villareal, T. A.:
Physiological and optical properties of Rhizosolenia formosa
(Bacillariophyceae) in the context of open-ocean vertical migration, J.
Phycol., 32, 741–757, 1996.
Richardson, T. L., Cullen, J. J., Kelley, D. E., and Lewis, M. R.: Potential
contributions of vertically migrating Rhizosolenia to nutrient cycling and
new production in the open ocean, J. Plankton Re., 20, 219–241, 1998.
Ricker, W. E.: Linear regressions in fishery research, J. Fish Res. Board
Can., 30, 409–434, 1973.
Rivkin, R. B. and Anderson, M. R.: Inorganic nutrient limitation of oceanic
bacterioplankton, Limnol. Oceanogr., 42, 730–740, 1997.
Rivkin, R. B., Swift, E., Biggley, W. H., and Voytek, M. A.: Growth and
carbon uptake by natural populations of oceanic dinoflagellates
Pyrocystis noctiluca and Pyrocystis fusiformis,
Deep-Sea Res. Pt. A, 31, 353–367, 1984.
Semina, H. J. and Levashova, S. S.: The biogeography of tropical
phytoplankton species in the Pacific Ocean, Int. Rev. Gesamten Hydrobiol.,
78, 243–262, 1993.
Semina, H. J., Belyayeva, T. V., Zernova, V. V., MovChan, O. A., Sanina, L.
V., Sukhanova, I. N., and Tarkhova, I. A.: Distribution of indicator species
of planktonic algae in the World Ocean, Oceanology, 17, 573–579, 1977.
Shipe, R. F., Brzezinski, M. A., Pilskaln, C., and Villareal, T. A.:
Rhizosolenia mats: An overlooked source of silica production in the
open sea, Limnol. Oceanogr., 44, 1282–1292, 1999.
Shulenberger, E. and Reid, J. L.: The Pacific shallow oxygen maximum, deep
chlorophyll maximum, and primary productivity, reconsidered, Deep-Sea Res.
Pt. A, 28, 901–919, 1981.
Singler, H. R. and Villareal, T. A.: Nitrogen inputs into the euphotic zone
by vertically migrating Rhizosolenia mats, J. Plankton Re., 27,
545–556, 2005.
Steemann Nielsen, E.: Über die vertikale Verbreitung der Phytoplanktonten
im Meere, Internationale Revue der gesamten Hydrobiologie und Hydrographie,
38, 421–440, https://doi.org/10.1002/iroh.19390380124, 1939.
Sukhanova, I. N.: Vertical distribution of some peridinians in the equatorial
Pacific Ocean, in: Life activities of pelagic communities in the ocean,
edited by: Vinogradov, M. E., Israeli Program Scientific Translation,
Jerusalem, 210–217, 1973.
Sukhanova, I. N. and Rudyakov, Y. A.: Population composition and vertical
distribution of Pyrocystis pseudonoctiluca (W. Thomson) in
the western equatorial Pacific, in: Life activities of pelagic communities in
the ocean, edited by: Vinogradov, M. E., Israeli Program Scientific
Translation, Jerusalem, 218–228, 1973.
Swift, E.: The marine diatom Ethmodiscus rex: its morphology and
occurrence in the plankton of the Sargasso Sea, J. Phycol., 2, 456–460,
1973.
Swift, E., Biggley, W. H., and Seliger, H. H.: Species of oceanic
dinoflagellates in genera Dissodinium and Pyrocystis:
Interclonal and interspecific comparisons of coloar and photon yield of
bioluminscence, J. Phycol., 9, 420–426,
https://doi.org/10.1111/j.0022-3646.1973.00420.x, 1973.
Swift, E., Stuart, M., and Meunier, V.: The in situ growth rates of
some deep-living oceanic dinoflagellates: Pyrocystis fusiformis and
Pyrocystis noctiluca, Limnol. Oceanogr., 21, 418–426, 1976.
Swift, E., Meunier, V. A., Biggley, W. H., Hoarau, J., and Barras, H.:
Factors affecting bioluminescence capacity in oceanic dinoflagellates, in:
Bioluminescence: current perspectives, edited by: Nealson, K. H., Burgess
Publishing Co., Minneapolis, 95–106, 1981.
Takahashi, T., Broecker, W. S., and Langer, S.: Redfield ratio based on
chemical data from isopycnal surfaces, J. Geophys. Res.-Oceans, 90,
6907–6924, 1985.
Teng, Y. C., Primeau, F. W., Moore, J. K., Lomas, M. W., and Martiny, A. C.:
Global-scale variations of the ratios of carbon to phosphorus in exported
marine organic matter, Nat. Geosci., 7, 895–898, 2014.
Toggweiler, J. R.: Carbon overconsumption, Nature, 363, 210–211, 1993.
Toggweiler, J. R.: Vanishing in Bermuda, Nature, 372, 505–506, 1994.
Trujillo-Ortiz, A. and Hernandez-Walls, R.: gmregress: Geometric Mean
Regression (Reduced Major Axis Regression), A MATLAB file, available at:
http://www.mathworks.com/matlabcentral/fileexchange/27918-gmregress (last access: 12 December 2017), 2010.
Venrick, E. L.: The distribution and ecology of oceanic diatoms in the North
Pacific, PhD, University of California, San Diego, 684 pp., 1969.
Villareal, T. A.: Abundance of the giant diatom Ethmodiscus in the
southwest Atlantic Ocean and central Pacific gyre, Diatom Research, 8,
171–177, 1993.
Villareal, T. A.: Single-cell pulse amplitude modulation fluorescence
measurements of the giant diatom Ethmodiscus (Bacillariophyceae), J. Phycol.,
40, 1052–1061, https://doi.org/10.1111/j.1529-8817.2004.03208.x, 2004.
Villareal, T. A. and Carpenter, E. J.: Nitrogen-fixation, suspension
characteristics and chemical composition of Rhizosolenia mats in the
central North Pacific Gyre, Biol. Oceanogr., 6, 327–345, 1989.
Villareal, T. A. and Carpenter, E. J.: Chemical composition and
photosynthetic characteristics of Ethmodiscus rex
(Bacillariophyceae): Evidence for vertical migration, J. Phycol., 30, 1–8,
1994.
Villareal, T. A. and Lipschultz, F.: Internal nitrate concentrations in
single cells of large phytoplankton from the Sargasso Sea, J. Phycol., 31,
689–696, 1995.
Villareal, T. A., Altabet, M. A., and Culver-Rymsza, K.: Nitrogen transport
by vertically migrating diatom mats in the North Pacific Ocean, Nature, 363,
709–712, 1993.
Villareal, T. A., Woods, S., Moore, J. K., and Culver-Rymsza, K.: Vertical
migration of Rhizosolenia mats and their significance to NO
Villareal, T. A., Joseph, L., Brzezinski, M. A., Shipe, R. F., Lipschultz,
F., and Altabet, M. A.: Biological and chemical characteristics of the giant
diatom Ethmodiscus (Bacillariophyceae) in the central North Pacific
gyre, J. Phycol., 35, 896–902, 1999a.
Villareal, T. A., Pilskaln, C., Brzezinski, M., Lipschultz, F., Dennett, M.,
and Gardner, G. B.: Upward transport of oceanic nitrate by migrating diatom
mats, Nature, 397, 423–425, 1999b.
Villareal, T. A., McKay, R. M. L., Al-Rshaidat, M. M. D., Boyanapalli, R.,
and Sherrell, R. M.: Compositional and fluorescence characteristics of the
giant diatom Ethmodiscus along a 3000 km transect (28∘ N)
in the central North Pacific gyre, Deep-Sea Res. Pt. I, 54 1273–1288, 2007.
Villareal, T. A., Pilskaln, C. H., Montoya, J. P., and Dennett, M.: Upward
nitrate transport by phytoplankton in oceanic waters: balancing nutrient
budgets in oligotrophic seas, PeerJ, 2, e302, https://doi.org/10.7717/peerj.302, 2014.
Walker, S. J., Weiss, R. F., and Salameh, P. K.: Reconstructed histories of
the annual mean atmospheric mole fractions for the halocarbons CFC-11,
CFC-12, CFC-113, and carbon tetrachloride, J. Geophys. Res.-Oceans, 105,
14285–14296, 2000.
Wallich, G. C.: On microscopic objects collected in India, T. Microscop. Soc.
London, 6, 81–87, 1858.
Warner, M. J. and Weiss, R. F.: Solubilities of chlorofluorocarbons 11 and 12
in water and seawater, Deep-Sea Res. Pt. A, 32, 1485–1497, 1985.
Wiebe, P. H., Remsen, C. C., and Vaccaro, R. F.: Halosphaera viridis
in the Mediterranean Sea: size range, vertical distribution, and potential
energy source for deep-sea benthos, in: Deep Sea Research and Oceanographic
Abstracts, Elsevier, 21, 657–667, 1974.
Williams, P. J. L. B., Quay, P. D., Westberry, T. K., and Behrenfeld, M. J.:
The oligotrophic ocean is autotrophic, Annu. Rev. Mar. Sci., 5, 535–549,
2013.
Woods, S. and Villareal, T. A.: Intracellular ion concentrations and cell sap
density in positively buoyant oceanic phytoplankton, Nova Hedwigia Beihefte,
133, 131–145, 2008.
Wurl, O., Miller, L., Röttgers, R., and Vagle, S.: The distribution and
fate of surface-active substances in the sea-surface microlayer and water
column, Mar. Chem., 115, 1–9, 2009.
Wurl, O., Miller, L., and Vagle, S.: Production and fate of transparent
exopolymer particles in the ocean, J. Geophys. Res.-Oceans, 116, C00H13,
https://doi.org/10.1029/2011JC007342, 2011.
Zweifel, U. L., Norrman, B., and Hagstrom, A.: Consumption of dissolved
organic carbon by marine bacteria and demand for inorganic nutrients, Mar.
Ecol. Prog. Ser., 101, 23–32, 1993.
Short summary
The formation rates of oxygen to nitrogen anomalies in the subtropical North Pacific and North Atlantic were estimated from time series data. We find that vertically migrating phytoplankton, which traverse ~ 100–150 m in the upper ocean over days to acquire nutrients from waters at depth and return to the surface for photosynthesis, likely explain the observed anomalies and help sustain surface ocean productivity and the biological pump throughout the annual cycle in the subtropical ocean.
The formation rates of oxygen to nitrogen anomalies in the subtropical North Pacific and North...
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