Articles | Volume 10, issue 9
https://doi.org/10.5194/bg-10-6019-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-10-6019-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
12 Sep 2013
Research article |
| 12 Sep 2013
Late Holocene variations in Pacific surface circulation and biogeochemistry inferred from proteinaceous deep-sea corals
T. P. Guilderson
Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, USA
Institute of Marine Sciences and Department of Ocean Sciences, University of California, Santa Cruz, CA, USA
M. D. McCarthy
Institute of Marine Sciences and Department of Ocean Sciences, University of California, Santa Cruz, CA, USA
R. B. Dunbar
Department of Environmental Earth System Science, Stanford University, Stanford, CA, USA
A. Englebrecht
Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, USA
E. B. Roark
Department of Environmental Earth System Science, Stanford University, Stanford, CA, USA
now at: Department of Geography, Texas A&M University, College Station, TX, USA
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Kate E. Ashley, Robert McKay, Johan Etourneau, Francisco J. Jimenez-Espejo, Alan Condron, Anna Albot, Xavier Crosta, Christina Riesselman, Osamu Seki, Guillaume Massé, Nicholas R. Golledge, Edward Gasson, Daniel P. Lowry, Nicholas E. Barrand, Katelyn Johnson, Nancy Bertler, Carlota Escutia, Robert Dunbar, and James A. Bendle
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Intense and localized export of selected marine snow types at eddy edges in the South Atlantic Ocean
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Climate-driven shifts in Southern Ocean primary producers and biogeochemistry in CMIP6 models
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Pelagic coccolithophore production and dissolution and their impacts on particulate inorganic carbon cycling in the western North Pacific
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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
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Key parameters representing the gravity flux in global models are the sinking speed and the vertical attenuation of the exported material. We calculate for the first time, these parameters in situ for 6 intermittent blooms followed by export events using high-resolution (3 days) time series of 0–1000 m depth profiles from imaging sensor mounted on an Argo float. We show that sinking speed depends not only on size but also on the morphology of the particles, density being an important property.
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.
Brandon Stephens, Montserrat Roca-Martí, Amy Maas, Vinícius Amaral, Samantha Clevenger, Shawnee Traylor, Claudia Benitez-Nelson, Philip Boyd, Ken Buesseler, Craig Carlson, Nicolas Cassar, Margaret Estapa, Andrea Fassbender, Yibin Huang, Phoebe Lam, Olivier Marchal, Susanne Menden-Deuer, Nicola Paul, Alyson Santoro, David Siegel, and David Nicholson
EGUsphere, https://doi.org/10.5194/egusphere-2024-2251, https://doi.org/10.5194/egusphere-2024-2251, 2024
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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 for the MZ in 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 time scales may help to close MZ carbon budgets.
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.
Kieran Curran, Tracy Villareal, and Robert T. Letscher
EGUsphere, https://doi.org/10.5194/egusphere-2024-1416, https://doi.org/10.5194/egusphere-2024-1416, 2024
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This work provides a two 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 for gel cycling during the summer months, helping explain previously contradictory estimates of nutrient supply and demand for the subtropical ocean.
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.
Allanah Joy Paul, Mathias Haunost, Silvan Urs Goldenberg, Jens Hartmann, Nicolás Sánchez, Julieta Schneider, Niels Suitner, and Ulf Riebesell
EGUsphere, https://doi.org/10.5194/egusphere-2024-417, https://doi.org/10.5194/egusphere-2024-417, 2024
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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 one 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.
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.
Alban Planchat, Lester Kwiatkowski, Laurent Bopp, Olivier Torres, James R. Christian, Momme Butenschön, Tomas Lovato, Roland Séférian, Matthew A. Chamberlain, Olivier Aumont, Michio Watanabe, Akitomo Yamamoto, Andrew Yool, Tatiana Ilyina, Hiroyuki Tsujino, Kristen M. Krumhardt, Jörg Schwinger, Jerry Tjiputra, John P. Dunne, and Charles Stock
Biogeosciences, 20, 1195–1257, https://doi.org/10.5194/bg-20-1195-2023, https://doi.org/10.5194/bg-20-1195-2023, 2023
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Ocean alkalinity is critical to the uptake of atmospheric carbon and acidification in surface waters. We review the representation of alkalinity and the associated calcium carbonate cycle in Earth system models. While many parameterizations remain present in the latest generation of models, there is a general improvement in the simulated alkalinity distribution. This improvement is related to an increase in the export of biotic calcium carbonate, which closer resembles observations.
Jérôme Pinti, Tim DeVries, Tommy Norin, Camila Serra-Pompei, Roland Proud, David A. Siegel, Thomas Kiørboe, Colleen M. Petrik, Ken H. Andersen, Andrew S. Brierley, and André W. Visser
Biogeosciences, 20, 997–1009, https://doi.org/10.5194/bg-20-997-2023, https://doi.org/10.5194/bg-20-997-2023, 2023
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Large numbers of marine organisms such as zooplankton and fish perform daily vertical migration between the surface (at night) and the depths (in the daytime). This fascinating migration is important for the carbon cycle, as these organisms actively bring carbon to depths where it is stored away from the atmosphere for a long time. Here, we quantify the contributions of different animals to this carbon drawdown and storage and show that fish are important to the biological carbon pump.
Alastair J. M. Lough, Alessandro Tagliabue, Clément Demasy, Joseph A. Resing, Travis Mellett, Neil J. Wyatt, and Maeve C. Lohan
Biogeosciences, 20, 405–420, https://doi.org/10.5194/bg-20-405-2023, https://doi.org/10.5194/bg-20-405-2023, 2023
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Iron is a key nutrient for ocean primary productivity. Hydrothermal vents are a source of iron to the oceans, but the size of this source is poorly understood. This study examines the variability in iron inputs between hydrothermal vents in different geological settings. The vents studied release different amounts of Fe, resulting in plumes with similar dissolved iron concentrations but different particulate concentrations. This will help to refine modelling of iron-limited ocean productivity.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
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The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Cited articles
Altabet, M. A.: Variations in nitrogen isotopic composition between sinking and suspended particles: implications for nitrogen cycling and particle transformation in the open ocean, Deep-Sea Res. II, 35, 535–554, 1988.
Altabet, M. A.: Nitrogen isotopic evidence for micronutrient control of fractional NO3 utilization in the equatorial Pacific, Limnol. Oceanog., 46, 368–380, 2001.
Athens, J. S., Ward, J. V., and Blinn, D. W.: Vegetation history of Laysan Island, Northwestern Hawaiian Islands, Pacific Science, 61, 17–37, 2007.
Bidigare, R. R., Benitez-Nelson, C, Leonard, C. L., Quay, P. D., Parsons, M. L., Foley, D. G., and Seki, M. P.: Influence of a cyclonic eddy on microheterotroph biomass and carbon export in the lee of Hawaii, Geophys. Res. Lett., 30, 1318, https://doi.org/10.1029/2002GL016393, 2003.
Boyce, D. G., Lewis, M. R., and Worm, B.: Global phytoplankton decline over the last century, Nature, 466, 591–596, https://doi.org/10.1038/nature09268, 2010.
Casciotti, K. L., Trull, T. W., Glover, D. M., and Davies, D.: Constraints on nitrogen cycling at the subtropical North Pacific Station ALOHA from isotopic measurements of nitrate and particulate nitrogen, Deep-Sea Res. II, 55, 1661–1672, 2008.
Chu, P.-S. and Chen, H.: Interannual and interdecadal rainfall variations in the Hawaiian Islands, J. Climate, 18, 4796–4813, 2005.
Church, M. J., Mahaffey, C., Letelier, R. M., Lukas, R., Zehr, J. P., and Karl, D. M.: Physical forcing of nitrogen fixation and diazotroph community structure in the North Pacific subtropical gyre, Global Biogoechem. Cy., 23, GB2020, https://doi.org/10.1029/2008GB003418, 2009.
Clement, A. C., Seager, R., and Cane, M. A.: Suppression of El Nino during the mid-Holocene by changes in the Earths's orbit, Paleoceanography, 15, 731–737, https://doi.org/10.1029/1999PA000466, 2000.
Corno, G., Karl, D. M., Church, M. J., Letelier, R. M., Lukas, R., Bidigare, R. B., and Abbott, M. A.: Impact of climate forcing on ecosystem processes in the North Pacific Subtropical Gyre, J. Geophys. Res., 112, C04021, https://doi.org/10.1029/2006JC003730, 2007.
Dean, W. E., Zheng, Y., Ortiz, J. D., and VanGeen, A.: Sediment Cd and Mo accumulation in the oxygen minimum zone off western Baja California linked to global climate over the past 52 kyr, Paleoceanography, 21, PA4209, https://doi.org/10.1029/2005PA001239, 2006.
Diaz, H. F. and Giambelluca, T. W.: Changes in atmospheric circulation patterns associated with high and low rainfall regimes in the Hawaiian Islands region on multiple time scales, Glob. Planet. Change, 98/99, 97–108, 2012.
Dore, J. E., Brum, J. R., Tupas, L. M., and Karl, D. M.: Seasonal and interannual variability in sources of nitrogen supporting export in the oligotrophic subtropical North Pacific Ocean, Limnol. Oceanogr, 47, 1595–1607, 2002.
Dore, J. E., Letelier, R. M., Church, M. J., Lukas, R., and Karl, D. M.: Summer phytoplankton blooms in the oligotrophic North Pacific subtropical gyre: Historical perspective and recent observations, Prog. Oceanogr., 76, 2–38, https://doi.org/10.1016/j.pocean.2007.10.002, 2008.
Druffel, E. R. M., Griffith, S., Guilderson, T. P., Kashgarian, M., Southon, J., and Schrag, D. P.: Changes of subtropical North Pacific radiocarbon and correlation with climate variability, Radiocarbon, 43, 15–25, 2001.
Eppley, R. W., Sharp, J. H., Renger, E. H., Perry, M. J., and Harrison, W. G.: Nitrogen assimilation by phytoplankton and other microorganisms in the surface waters of the central North Pacific Ocean, Mar. Biol., 39, 111–120, 1977.
Fine, R. C., Peterson, W. J., and Ostlund, H. G.: The penetration of tritium into the tropical Pacific, J. Phys. Oceanography, 17, 553–564, 1987.
Firing, J. and Brainard, R. E.: Ten years of shipboard ADCP measurements along the Northwestern Hawaiian Islands, Atoll Res. Bull 543, 347–363, 2006.
Flament, P.: The Ocean Atlas of Hawaii, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, HI, 1996.
Ganeshram, R. S., Pedersen, T. F., Calvert, S. E., McNeill, G. W., and Fontugne, M. R.: Glacial-interglacial variability in denitrificaiton in the world's oceans: Causes and consequences, Paleoceanography, 15, 361–376, 2000.
Georicke, R. and Fry, B.: Variations of marine plankton $\delta ^13$C with latitude, temperature, and dissolved CO2 in the world ocean, Global Biogeochem. Cy., 8, 85–90, 1994.
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. I, 45, 673–717, 1998.
Heikoop, J. M., Hickmott, D. D., Risk, M. J., Shearer, C. K., and Atudorei, V.: Potential climate signals from the deep-sea gorgonian coral Primnoa resedaeformis, Hydrobiologia, 471, 117–124, 2002.
Karl, D. M.: A sea of change: Biogeochemical Variability in the North Pacific Subtropical Gyre, Ecosystems, 2, 181–214, 1999.
Karl, D. M. and Lukas, R.: The Hawaii Ocean Time-series (HOT) program: Background, rationale and field implementation, Deep Sea Res. II, 43, 129–156, 1996.
Karl, D. M., Michaels, A., Bergman, B., Capone, D., Carpenter, E., Letelier, R., Lipschultz, F., Paerl, H., Sigman, D., and Stal, L.: Dinitrogen fixation in the world's oceans, Biogeochemistry, 57/58, 47–98, 2002.
Karl, D. M., Bidigigae, R. R.,Church, M. J., Dore, J. E., Letelier, R. M., Mahaffey, C., and Zehr, J. P.: The nitrogen cycle in the North Pacific Trades biome: An Evolving Paradigm, in: Nitrogen in the Marine Environment, edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and Carpenter, E. J., Academic Press, 705–769, https://doi.org/10.1016/B978-0-12-372522-6.00016-5, 2008.
Kienast, S. S., Calvert, S. E., and Pederson, T. F.: Nitrogen isotope and productivity variations along the northeast Pacific margin over the last 120 kyr: Surface and subsurface paleoceanography, Paleoceanography, 17, 1055, https://doi.org/10.1029/2001PA000650, 2002.
Kienast, M., Lehmann, M. F., Timmerman, A., Galbraith, E., Bolliet, T., Holbourn, A., Normandeau, C., and Laj, C.: A mid-Holocene transition in the nitrogen dynamics of the western equatorial Pacific: Evidence of a deepening thermocline?, Geophys. Res. Letts., 35, L23610, https://doi.org/10.1029/2008GL035464, 2008.
Kroopnick, P. M.: The dissolved O2-CO2-13C system in the eastern equatorial Pacific, Deep-Sea Res., 21, 211–227, 1974.
Kroopnick, P. M.: The distribution of 13C of ΣCO2 in the world oceans, Deep-Sea Res., 32, 57–84, 1985.
Laws, E. A., Popp, B. N., Bidigare, R. R., Kennicutt, M. C., and Macko, S. A.: Dependence of phytoplankton carbon isotopic composition on growth rate and [CO2]aq: Theoretical considerations and experimental results, Geochim., Cosmochim. Acta, 59, 1131–1138, 1995.
Luo, Y-W., Ducklow, H. W., Friedrichs, M. A. M., Church, M. J., Karl, D. M., and Doney, S. C.: Interannual variability of primary productivity and dissolved organic nitrogen storage in the North Pacific Subtropical Gyre, J. Geophys. Res., 117, G03019, https://doi.org/10.1029/2011JG001830, 2012.
Maranon, E., Behrenfeld, M. J., González, N., Mouriño, B., and Zubkov, M. V.:. High variability of primary production in oligotrophic waters of the Atlantic Ocean: uncoupling from phytoplankton biomass and size structure, Mar. Ecol. Prog. Ser., 257, 1–11, 2003.
Osterberg, E., Mayewski, P., Kreutz, K., Fisher, D., Handley, M., Sneed, S., Zdanowicz, C., Zheng, J., Demuth, M., Waskiewicz, M., and Bourgeois, J.: Ice core record of rising lead pollution in the North Pacific atmosphere, Geophys. Res. Lett., 35, L05810, https://doi.org/10.1029/2007GL032680, 2008.
Quay, P. D. and Stutsman, J.: Surface layer carbon budget for the subtropical N, Pacific: d13C constraints at station ALOHA, Deep-Sea Res. Pt. I, 50, 1045–1061, 2003.
Rafter, P. A., Sigman, D. M., Charles, C. D., Kaiser, J., and Haug, G. H.: Subsurface tropical Pacific nitrogen isotopic composition of nitrate: Biogeochemical signals and their transport, Global Biogeochem. Cy., 26, GB1003, https://doi.org/10.1029/2010GB003979, 2012.
Reimer, P. J., Baillie, M. G. L., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Bronk-Ramsey, C., Buck, C. E., Burr, G. S., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Hadjas, I., Heaton, T. J., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., McCormac, F. G., Manning, S., Reimer, R. W., Richards, D. A., Southon, J. R., Talamo, S., Turney, C. S. M., van der Plicht, J., and Weyhenmeyer, C. E.: Intcal09 and Marine09 Radiocarbon Age Calibration Curves, 0–50 000 years CAL BP, Radiocarbon, 51, 1111–1150, 2009.
Roark, E. B., Guilderson, T. P., Flood-Page, S., Dunbar, R. B., Ingram, B. L., Fallon, S. J., and McCulloch, M.: Radiocarbon-based ages and growth rates of bamboo corals from the Gulf of Alaska, Geophys. Res. Lett., 32, https://doi.org/10.1029/2004GL021919, 2005.
Roark, E. B., Guilderson, T. P., Dunbar, R. B., and Ingram, B. L.: Radiocarbon based ages and growth rates: Hawaiian deep sea corals, Mar. Ecol. Prog. Ser., 327, 1–14, 2006.
Roark, E. B., Guilderson, T. P., Dunbar, R. B., Fallon, S., and Mucciarone, D. A.: Extreme longevity in proteinaceous deep-sea corals, Proc. Natl. Acad. Sci., 6, 5204–5208, https://doi.org/10.1073/pnas.0810875106, 2009.
Ryther, J. H.: Potential productivity of the sea, Science, 130, 602–608, 1959.
Sherwood, O. A., Heikoop, J. M., Scott, D. B., Risk, M. J., Guilderson, T. P., and McKinney, R. A.: Stable isotopic composition of deep-sea gorgonian corals Primnoa spp.: a new archive of surface processes, Mar. Ecol. Prog. Ser., 301, 135–148, 2005.
Sherwood O. A., Scott, D. B., and Risk, M. J.: Late Holocene radiocarbon dating and aspartic acid racemization dating of deep-sea octocorals. Geochim. Cosmochim, Acta, 70, 2806–2814, https://doi.org/10.1016/j.gca.2006.03.011, 2006.
Sherwood O. A., Thresher, R. E., Fallon, S. J., Davies, D. M., and Trull, T. W.: Multi-century time-series of 15N and 14C in bamboo corals from deep Tasmanian seamounts: evidence for stable oceanographic conditions, Mar. Ecol. Prog. Ser., 397, 209–218, 2009.
Sherwood, O. A., Lehmann, M. F., Schubert, C. J., Scott, D. B., and McCarthy, M. D.: Nutrient regime shift in the western North Atlantic indicated by compound-specific δ15N of deep-sea gorgonian corals, Proc. Nat. Acad. Sci., 108, 1011–1015, https://doi.org/10.1073/pnas.1004904108, 2011.
Sinninger, F., Ocaña, O. V., and Baco, A. R.: Diversity of Zoanthids (Anthozoa: Hexacorallia) on Hawaiian Seamounts: Description of the Hawaiian Gold Coral and Additional Zoanthids, PLoS ONE, 8, e52607, https://doi.org/10.1371/journa.pone.0052607, 2013.
Smith, J. J., Fischer, H., Wahlen, M., Mastroianni, D., and Deck, B.: Dual modes of the carbon cycle since the last glacial maximum, Nature, 400, 248–250, 1999.
Stanley, G. D. and Cairns, S. D.: Constructional Azooxanthellate coral communities: an overview with implications for the fossil record, Palaios, 3, 233–242, 1988.
Stuiver, M. and Polach, H. A.: Discussion reporting of 14C data, Radiocarbon, 19, 355–363, 1977.
Tourre, Y. M., Rajagopalan, B., Kushnir, Y., Barlow, M., and White, W. B.: Patterns of coherent decadal and interdecadal climate signals in the Pacific Basin during the 20th century, Geophys. Res. Lett., 28, 2069–2072, 2001.
Uchikawa, J., Popp, B. N., Schoonmaker, J. E., Timmermann, A., and Lorenz, S. J.: Geochemical and climate modeling evidence for Holocene aridificaiton in Hawaii: dynamic response to a weakening equatorial cold tongue, Quat. Sci. Rev., 29, 3057–3066, 2010.
Wakeham, S. G., Lee, C., Hedges, J. I., Hernes, P. J., and Peterson, M. L.: Molecular indicators of diagenetic status in marine organic matter, Geochim. Cosmochim, Acta, 61, 5363–5369, 1997.
Warner, M. J., Bullister, J. L., Wisegarver, D. P., Gammon, R. J., and Weiss, R. F.: Basin-wide distributions of chlorofluorocarbons CFC-11 and CFC-12 n the North Pacific: 1985–1989, J. Geophys. Res., 101, 20525–20542, 1996.
Wheatcroft, R.A., Jumars, P. A., Smith, C. R., and Nowell, A. R. M.: A mechanistic view of the particulate biodiffusion coefficient: step lengths, rest periods, and transport directions, J. Mar. Res., 48, 177–207, 1990.
Williams, B., Risk, M. J., Ross, S. W., and Sulak, K. J.: Deep-water antipatharians: Proxies of environmental change, Geology, 34, 773–776, 2006.
Zaunbrecher, L. K., Cobb, K. M., Beck, J. W., Charles, C. D., Druffel, E. R. M., Fairbanks, R. G., Griffin, S., and Sayani, H. R.: Coral records of central tropical Pacific radiocarbon variability during the last millennium, Paleoceanography, 25, PA4212, https://doi.org/10.1029/2009PA001788, 2010.
Zhang, J. and Quay, P. D.: The total organic carbon export rate based on 13C and 12C of DIC budgets in the equatorial Pacific region, Deep-Sea Res. II, 44, 2163–2190, 1997.
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