Articles | Volume 17, issue 23
https://doi.org/10.5194/bg-17-6051-2020
© Author(s) 2020. 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-17-6051-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Reviews and syntheses
| 
04 Dec 2020
Reviews and syntheses |
| 04 Dec 2020
| 04 Dec 2020
Reviews and syntheses: Present, past, and future of the oxygen minimum zone in the northern Indian Ocean
Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstr. 6, 28359
Bremen, Germany
Greg Cowie
School of Geosciences, University of Edinburgh, James Hutton Road,
Edinburgh EH9 3FE, Scotland, UK
Birgit Gaye
Institute for Geology, Universität Hamburg, Bundesstraße 55, 20146
Hamburg, Germany
Joaquim Goes
Marine Biology, Department of Marine Biology and Paleoenvironment, Lamont–Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades,
New York 10964, USA
Helga do Rosário Gomes
Marine Biology, Department of Marine Biology and Paleoenvironment, Lamont–Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades,
New York 10964, USA
Raleigh R. Hood
Horn Point Laboratory, University of Maryland Center for Environmental
Science, P.O. Box 775, Cambridge, MD 21613, USA
Zouhair Lachkar
Center for Prototype Climate Modeling (CPCM), NYU, Abu Dhabi, UAE
Henrike Schmidt
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel, Duesternbrooker Weg 20,
24105 Kiel, Germany
Joachim Segschneider
Institute of Geosciences, Christian-Albrechts-Universität zu Kiel (CAU),
Ludewig-Meyn-Straße 10, 24118 Kiel, Germany
Arvind Singh
Geosciences Division, Physical Research Laboratory (PRL) Navrangpura,
Ahmedabad 380 009, India
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Henrike Schmidt, Julia Getzlaff, Ulrike Löptien, and Andreas Oschlies
Ocean Sci., 17, 1303–1320, https://doi.org/10.5194/os-17-1303-2021, https://doi.org/10.5194/os-17-1303-2021, 2021
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Nicole Burdanowitz, Tim Rixen, Birgit Gaye, and Kay-Christian Emeis
Clim. Past, 17, 1735–1749, https://doi.org/10.5194/cp-17-1735-2021, https://doi.org/10.5194/cp-17-1735-2021, 2021
Short summary
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Derara Hailegeorgis, Zouhair Lachkar, Christoph Rieper, and Nicolas Gruber
Biogeosciences, 18, 303–325, https://doi.org/10.5194/bg-18-303-2021, https://doi.org/10.5194/bg-18-303-2021, 2021
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Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Ocean Sci., 16, 1459–1474, https://doi.org/10.5194/os-16-1459-2020, https://doi.org/10.5194/os-16-1459-2020, 2020
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Our investigations give detailed insight on the seasonally changing current system at intermediate depth in the Arabian Sea that is influenced by the monsoon. The changing currents influence the oxygen transport in the interior ocean and thus allow us to draw conclusions on the maintenance and seasonal variability of the upper part of the oxygen minimum zone in the Arabian Sea.
Shan Jiang, Moritz Müller, Jie Jin, Ying Wu, Kun Zhu, Guosen Zhang, Aazani Mujahid, Tim Rixen, Mohd Fakharuddin Muhamad, Edwin Sien Aun Sia, Faddrine Holt Ajon Jang, and Jing Zhang
Biogeosciences, 16, 2821–2836, https://doi.org/10.5194/bg-16-2821-2019, https://doi.org/10.5194/bg-16-2821-2019, 2019
Short summary
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Three cruises were conducted in the Rajang River estuary, Malaysia. The results revealed that the decomposition of terrestrial organic matter and the subsequent soil leaching were the main sources of dissolved inorganic nitrogen (DIN) in the fresh river water. Porewater exchange and ammonification enhanced DIN concentrations in the estuary water, while intensities of DIN addition varied between seasons. The riverine DIN flux could reach 101.5 ton(N) / d, supporting the coastal primary producers.
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The Indian Ocean subtropical gyre is a large oligotrophic area that is likely to adjust to continued warming by increasing stratification, reduced nutrient supply and decreasing biological production. In this study, we investigated concentrations of nutrients and stable isotopes of nitrate. We determine the lateral influence of water masses entering the gyre from the northern Indian Ocean and from the Southern Ocean and quantify the input of nitrogen by N2 fixation into the surface layer.
Malte Heinemann, Joachim Segschneider, and Birgit Schneider
Geosci. Model Dev., 12, 1869–1883, https://doi.org/10.5194/gmd-12-1869-2019, https://doi.org/10.5194/gmd-12-1869-2019, 2019
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Ocean CO2 uptake played a crucial role for the global cooling during ice ages. Dust formation, e.g. by ice scraping over bedrock, potentially contributed to this CO2 uptake because (1) the iron in the dust is a fertilizer and (2) the heavy dust particles can accelerate sinking organic matter (ballasting hypothesis). This study tests the glacial dust ballasting hypothesis for the first time, using an ocean model. It turns out, however, that the ballasting effect probably played a minor role.
Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-168, https://doi.org/10.5194/bg-2019-168, 2019
Manuscript not accepted for further review
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Our investigations give a detailed insight on the changing current system at intermediate depth in the Arabian Sea and allow to draw conclusions on ventilation pathways of the oxygen minimum zone and its seasonal variability. In response to the monsoon system the boundary currents change direction and feature a regionally varying ventilation pattern.
Tim Rixen, Birgit Gaye, Kay-Christian Emeis, and Venkitasubramani Ramaswamy
Biogeosciences, 16, 485–503, https://doi.org/10.5194/bg-16-485-2019, https://doi.org/10.5194/bg-16-485-2019, 2019
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Data obtained from sediment trap experiments in the Indian Ocean indicate that lithogenic matter ballast increases organic carbon flux rates on average by 45 % and by up to 62 % at trap locations in the river-influenced regions of the Indian Ocean. Such a strong lithogenic matter ballast effect implies that land use changes and the associated enhanced transport of lithogenic matter may significantly affect the CO2 uptake of the organic carbon pump in the receiving ocean areas.
Denise Müller-Dum, Thorsten Warneke, Tim Rixen, Moritz Müller, Antje Baum, Aliki Christodoulou, Joanne Oakes, Bradley D. Eyre, and Justus Notholt
Biogeosciences, 16, 17–32, https://doi.org/10.5194/bg-16-17-2019, https://doi.org/10.5194/bg-16-17-2019, 2019
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Southeast Asian peat-draining rivers are potentially strong sources of carbon to the atmosphere due to the large amounts of organic carbon stored in those ecosystems. We present the first assessment of CO2 emissions from the Rajang River, the largest peat-draining river in Malaysia. The peatlands’ influence on the CO2 emissions from the Rajang River was smaller than expected, probably due to their proximity to the coast. Therefore, the Rajang was only a moderate source of CO2 to the atmosphere.
Joachim Segschneider, Birgit Schneider, and Vyacheslav Khon
Biogeosciences, 15, 3243–3266, https://doi.org/10.5194/bg-15-3243-2018, https://doi.org/10.5194/bg-15-3243-2018, 2018
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To gain a better understanding of climate and marine biogeochemistry variations over the last 9500 years (the Holocene), we performed non-accelerated model simulations with a global coupled climate and biogeochemistry model forced by orbital parameters and atmospheric greenhouse gases. One main outcome is an increase in the volume of the eastern equatorial Pacific oxygen minimum zone, driven by a slowdown of the large-scale circulation.
Celeste Sánchez-Noguera, Ines Stuhldreier, Jorge Cortés, Carlos Jiménez, Álvaro Morales, Christian Wild, and Tim Rixen
Biogeosciences, 15, 2349–2360, https://doi.org/10.5194/bg-15-2349-2018, https://doi.org/10.5194/bg-15-2349-2018, 2018
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The Papagayo upwelling system is a natural laboratory for studying ecosystems' response to ocean acidification (OA). We measured pH and pCO2 in situ with high temporal resolution and compared them with data available from upwelling season. Local coral reefs are exposed to acidic and undersaturated waters in upwelling and non-upwelling events. These restrictive conditions occur alongside local stressors, potentially decreasing reefs' resilience and increasing their vulnerability under future OA.
Birgit Gaye, Anna Böll, Joachim Segschneider, Nicole Burdanowitz, Kay-Christian Emeis, Venkitasubramani Ramaswamy, Niko Lahajnar, Andreas Lückge, and Tim Rixen
Biogeosciences, 15, 507–527, https://doi.org/10.5194/bg-15-507-2018, https://doi.org/10.5194/bg-15-507-2018, 2018
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The Arabian Sea has one of the most severe oxygen minima of the world's oceans between about 100 and 1200 m of water depth and is therefore a major oceanic nitrogen sink. Stable nitrogen isotopic ratios in sediments record changes in oxygen concentrations and were studied for the last 25 kyr. Oxygen concentrations dropped at the end of the last glacial and became further reduced during the Holocene, probably due to the increasing age of the low-oxygen water mass.
Zouhair Lachkar, Marina Lévy, and Shafer Smith
Biogeosciences, 15, 159–186, https://doi.org/10.5194/bg-15-159-2018, https://doi.org/10.5194/bg-15-159-2018, 2018
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This study provides a new contribution to our understanding of the coupling between the oxygen minimum zones (OMZs) and climate. It explores how idealized changes in summer and winter Indian monsoon winds affect the productivity of the Arabian Sea and the size and intensity of its OMZ. We find that intensification of Indian monsoon winds can amplify climate warming on decadal to centennial timescales.
Tim Rixen, Birgit Gaye, Kay-Christian Emeis, and Venkitasubramani Ramaswamy
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-317, https://doi.org/10.5194/bg-2017-317, 2017
Manuscript not accepted for further review
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Sediment trap experiments showed that in the river-influenced regions of the Indian Ocean lithogenic matter supplied from land controls the organic carbon export into the deep sea via its ballast effect in sinking particles. Carbonate produced by plankton is the main ballast material in the open ocean. The ballast effect increases the CO2 uptake of the organic carbon pump by enhancing the amount of nutrients used to bind CO2 and by favouring the sedimentation of organic matter.
Elisa Lovecchio, Nicolas Gruber, Matthias Münnich, and Zouhair Lachkar
Biogeosciences, 14, 3337–3369, https://doi.org/10.5194/bg-14-3337-2017, https://doi.org/10.5194/bg-14-3337-2017, 2017
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We find that a big portion of the phytoplankton, zooplankton, and detrital organic matter produced near the northern African coast is laterally transported towards the open North Atlantic. This offshore flux sustains a relevant part of the biological activity in the open sea and reaches as far as the middle of the North Atlantic. Our results, obtained with a state-of-the-art model, highlight the fundamental role of the narrow but productive coastal ocean in sustaining global marine life.
Alex R. Baker, Maria Kanakidou, Katye E. Altieri, Nikos Daskalakis, Gregory S. Okin, Stelios Myriokefalitakis, Frank Dentener, Mitsuo Uematsu, Manmohan M. Sarin, Robert A. Duce, James N. Galloway, William C. Keene, Arvind Singh, Lauren Zamora, Jean-Francois Lamarque, Shih-Chieh Hsu, Shital S. Rohekar, and Joseph M. Prospero
Atmos. Chem. Phys., 17, 8189–8210, https://doi.org/10.5194/acp-17-8189-2017, https://doi.org/10.5194/acp-17-8189-2017, 2017
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Man's activities have greatly increased the amount of nitrogen emitted into the atmosphere. Some of this nitrogen is transported to the world's oceans, where it may affect microscopic marine plants and cause ecological problems. The huge size of the oceans makes direct monitoring of nitrogen inputs impossible, so computer models must be used to assess this issue. We find that current models reproduce observed nitrogen deposition to the oceans reasonably well and recommend future improvements.
Roland Séférian, Marion Gehlen, Laurent Bopp, Laure Resplandy, James C. Orr, Olivier Marti, John P. Dunne, James R. Christian, Scott C. Doney, Tatiana Ilyina, Keith Lindsay, Paul R. Halloran, Christoph Heinze, Joachim Segschneider, Jerry Tjiputra, Olivier Aumont, and Anastasia Romanou
Geosci. Model Dev., 9, 1827–1851, https://doi.org/10.5194/gmd-9-1827-2016, https://doi.org/10.5194/gmd-9-1827-2016, 2016
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This paper explores how the large diversity in spin-up protocols used for ocean biogeochemistry in CMIP5 models contributed to inter-model differences in modeled fields. We show that a link between spin-up duration and skill-score metrics emerges from both individual IPSL-CM5A-LR's results and an ensemble of CMIP5 models. Our study suggests that differences in spin-up protocols constitute a source of inter-model uncertainty which would require more attention in future intercomparison exercises.
Denise Müller, Hermann W. Bange, Thorsten Warneke, Tim Rixen, Moritz Müller, Aazani Mujahid, and Justus Notholt
Biogeosciences, 13, 2415–2428, https://doi.org/10.5194/bg-13-2415-2016, https://doi.org/10.5194/bg-13-2415-2016, 2016
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Estuaries act as sources of the greenhouse gases nitrous oxide (N2O) and methane (CH4) to the atmosphere. We provide first measurements of N2O and CH4 in two estuaries in north-western Borneo, a region which is dominated by peatlands. We show that N2O and CH4 concentrations in these estuaries are moderate despite high organic carbon loads, that nutrient enhancement does not lead to enhanced N2O emissions, and that the wet season dominates the variability of the emissions in these systems.
Isaac D. Irby, Marjorie A. M. Friedrichs, Carl T. Friedrichs, Aaron J. Bever, Raleigh R. Hood, Lyon W. J. Lanerolle, Ming Li, Lewis Linker, Malcolm E. Scully, Kevin Sellner, Jian Shen, Jeremy Testa, Hao Wang, Ping Wang, and Meng Xia
Biogeosciences, 13, 2011–2028, https://doi.org/10.5194/bg-13-2011-2016, https://doi.org/10.5194/bg-13-2011-2016, 2016
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A comparison of eight hydrodynamic-oxygen models revealed that while models have difficulty resolving key drivers of dissolved oxygen (DO) variability, all models exhibit skill in reproducing the variability of DO itself. Further, simple oxygen models and complex biogeochemical models reproduced observed DO variability similarly well. Future advances in hypoxia simulations will depend more on the ability to reproduce the depth of the mixed layer than the degree of the vertical density gradient.
D. Müller, T. Warneke, T. Rixen, M. Müller, A. Mujahid, H. W. Bange, and J. Notholt
Biogeosciences, 13, 691–705, https://doi.org/10.5194/bg-13-691-2016, https://doi.org/10.5194/bg-13-691-2016, 2016
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We studied organic carbon and the dissolved greenhouse gases carbon dioxide (CO2) and carbon monoxide (CO) in two estuaries in Sarawak, Malaysia, whose coast is covered by carbon-rich peatlands. The estuaries received terrestrial organic carbon from peat-draining tributaries. A large fraction was converted to CO2 and a minor fraction to CO. Both gases were released to the atmosphere. This shows how these estuaries function as efficient filters between land and ocean in this important region.
A. Singh, S. E. Baer, U. Riebesell, A. C. Martiny, and M. W. Lomas
Biogeosciences, 12, 6389–6403, https://doi.org/10.5194/bg-12-6389-2015, https://doi.org/10.5194/bg-12-6389-2015, 2015
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Stoichiometry of macronutrients in the subtropical ocean is important to understand how biogeochemical cycles are coupled. We observed that elemental stoichiometry was much higher in the dissolved organic-matter pools than in the particulate organic matter pools. In addition ratios vary with depth due to changes in growth rates of specific phytoplankton groups, namely cyanobacteria. These data will improve biogeochemical models by placing observational constraints on these ratios.
D. Müller, T. Warneke, T. Rixen, M. Müller, S. Jamahari, N. Denis, A. Mujahid, and J. Notholt
Biogeosciences, 12, 5967–5979, https://doi.org/10.5194/bg-12-5967-2015, https://doi.org/10.5194/bg-12-5967-2015, 2015
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Tropical peatlands are an important source of organic carbon to rivers. However, due to the remoteness of these ecosystems, data are scarce. We present the first combined assessment of both lateral organic carbon fluxes and CO2 emissions from an undisturbed tropical peat-draining river. Compared to the organic carbon concentrations, CO2 fluxes to the atmosphere were actually relatively moderate, which we attributed to the short water residence time.
C. Le Quéré, R. Moriarty, R. M. Andrew, G. P. Peters, P. Ciais, P. Friedlingstein, S. D. Jones, S. Sitch, P. Tans, A. Arneth, T. A. Boden, L. Bopp, Y. Bozec, J. G. Canadell, L. P. Chini, F. Chevallier, C. E. Cosca, I. Harris, M. Hoppema, R. A. Houghton, J. I. House, A. K. Jain, T. Johannessen, E. Kato, R. F. Keeling, V. Kitidis, K. Klein Goldewijk, C. Koven, C. S. Landa, P. Landschützer, A. Lenton, I. D. Lima, G. Marland, J. T. Mathis, N. Metzl, Y. Nojiri, A. Olsen, T. Ono, S. Peng, W. Peters, B. Pfeil, B. Poulter, M. R. Raupach, P. Regnier, C. Rödenbeck, S. Saito, J. E. Salisbury, U. Schuster, J. Schwinger, R. Séférian, J. Segschneider, T. Steinhoff, B. D. Stocker, A. J. Sutton, T. Takahashi, B. Tilbrook, G. R. van der Werf, N. Viovy, Y.-P. Wang, R. Wanninkhof, A. Wiltshire, and N. Zeng
Earth Syst. Sci. Data, 7, 47–85, https://doi.org/10.5194/essd-7-47-2015, https://doi.org/10.5194/essd-7-47-2015, 2015
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Carbon dioxide (CO2) emissions from human activities (burning fossil fuels and cement production, deforestation and other land-use change) are set to rise again in 2014.
This study (updated yearly) makes an accurate assessment of anthropogenic CO2 emissions and their redistribution between the atmosphere, ocean, and terrestrial biosphere in order to better understand the global carbon cycle, support the development of climate policies, and project future climate change.
P. G. Strutton, V. J. Coles, R. R. Hood, R. J. Matear, M. J. McPhaden, and H. E. Phillips
Biogeosciences, 12, 2367–2382, https://doi.org/10.5194/bg-12-2367-2015, https://doi.org/10.5194/bg-12-2367-2015, 2015
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In 2010, a first-of-its-kind deployment of biological sensors on a mooring in the central Indian Ocean revealed interesting variability in chlorophyll (a proxy for ocean productivity) at timescales of about 2 weeks. Using the mooring data with satellite observations and a biogeochemical model, it was determined that local wind mixing and entrainment, rather than mixed Rossby gravity waves, were likely responsible for much of the observed variability.
F. Fendereski, M. Vogt, M. R. Payne, Z. Lachkar, N. Gruber, A. Salmanmahiny, and S. A. Hosseini
Biogeosciences, 11, 6451–6470, https://doi.org/10.5194/bg-11-6451-2014, https://doi.org/10.5194/bg-11-6451-2014, 2014
T. Rixen, A. Baum, B. Gaye, and B. Nagel
Biogeosciences, 11, 5733–5747, https://doi.org/10.5194/bg-11-5733-2014, https://doi.org/10.5194/bg-11-5733-2014, 2014
W. Koeve, O. Duteil, A. Oschlies, P. Kähler, and J. Segschneider
Geosci. Model Dev., 7, 2393–2408, https://doi.org/10.5194/gmd-7-2393-2014, https://doi.org/10.5194/gmd-7-2393-2014, 2014
M. R. Stukel, V. J. Coles, M. T. Brooks, and R. R. Hood
Biogeosciences, 11, 3259–3278, https://doi.org/10.5194/bg-11-3259-2014, https://doi.org/10.5194/bg-11-3259-2014, 2014
C. Le Quéré, G. P. Peters, R. J. Andres, R. M. Andrew, T. A. Boden, P. Ciais, P. Friedlingstein, R. A. Houghton, G. Marland, R. Moriarty, S. Sitch, P. Tans, A. Arneth, A. Arvanitis, D. C. E. Bakker, L. Bopp, J. G. Canadell, L. P. Chini, S. C. Doney, A. Harper, I. Harris, J. I. House, A. K. Jain, S. D. Jones, E. Kato, R. F. Keeling, K. Klein Goldewijk, A. Körtzinger, C. Koven, N. Lefèvre, F. Maignan, A. Omar, T. Ono, G.-H. Park, B. Pfeil, B. Poulter, M. R. Raupach, P. Regnier, C. Rödenbeck, S. Saito, J. Schwinger, J. Segschneider, B. D. Stocker, T. Takahashi, B. Tilbrook, S. van Heuven, N. Viovy, R. Wanninkhof, A. Wiltshire, and S. Zaehle
Earth Syst. Sci. Data, 6, 235–263, https://doi.org/10.5194/essd-6-235-2014, https://doi.org/10.5194/essd-6-235-2014, 2014
E. J. D'Sa, J. I. Goes, H. Gomes, and C. Mouw
Biogeosciences, 11, 3225–3244, https://doi.org/10.5194/bg-11-3225-2014, https://doi.org/10.5194/bg-11-3225-2014, 2014
A. Flohr, A. K. van der Plas, K.-C. Emeis, V. Mohrholz, and T. Rixen
Biogeosciences, 11, 885–897, https://doi.org/10.5194/bg-11-885-2014, https://doi.org/10.5194/bg-11-885-2014, 2014
G. Turi, Z. Lachkar, and N. Gruber
Biogeosciences, 11, 671–690, https://doi.org/10.5194/bg-11-671-2014, https://doi.org/10.5194/bg-11-671-2014, 2014
B. Gaye, B. Nagel, K. Dähnke, T. Rixen, N. Lahajnar, and K.-C. Emeis
Biogeosciences, 10, 7689–7702, https://doi.org/10.5194/bg-10-7689-2013, https://doi.org/10.5194/bg-10-7689-2013, 2013
V. Cocco, F. Joos, M. Steinacher, T. L. Frölicher, L. Bopp, J. Dunne, M. Gehlen, C. Heinze, J. Orr, A. Oschlies, B. Schneider, J. Segschneider, and J. Tjiputra
Biogeosciences, 10, 1849–1868, https://doi.org/10.5194/bg-10-1849-2013, https://doi.org/10.5194/bg-10-1849-2013, 2013
F. Joos, R. Roth, J. S. Fuglestvedt, G. P. Peters, I. G. Enting, W. von Bloh, V. Brovkin, E. J. Burke, M. Eby, N. R. Edwards, T. Friedrich, T. L. Frölicher, P. R. Halloran, P. B. Holden, C. Jones, T. Kleinen, F. T. Mackenzie, K. Matsumoto, M. Meinshausen, G.-K. Plattner, A. Reisinger, J. Segschneider, G. Shaffer, M. Steinacher, K. Strassmann, K. Tanaka, A. Timmermann, and A. J. Weaver
Atmos. Chem. Phys., 13, 2793–2825, https://doi.org/10.5194/acp-13-2793-2013, https://doi.org/10.5194/acp-13-2793-2013, 2013
J. Segschneider, A. Beitsch, C. Timmreck, V. Brovkin, T. Ilyina, J. Jungclaus, S. J. Lorenz, K. D. Six, and D. Zanchettin
Biogeosciences, 10, 669–687, https://doi.org/10.5194/bg-10-669-2013, https://doi.org/10.5194/bg-10-669-2013, 2013
P. Wang, A. B. Burd, M. A. Moran, R. R. Hood, V. J. Coles, and P. L. Yager
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-815-2013, https://doi.org/10.5194/bgd-10-815-2013, 2013
Revised manuscript not accepted
C. Hauri, N. Gruber, M. Vogt, S. C. Doney, R. A. Feely, Z. Lachkar, A. Leinweber, A. M. P. McDonnell, M. Munnich, and G.-K. Plattner
Biogeosciences, 10, 193–216, https://doi.org/10.5194/bg-10-193-2013, https://doi.org/10.5194/bg-10-193-2013, 2013
Related subject area
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Hydrological cycle amplification imposes spatial patterns on the climate change response of ocean pH and carbonate chemistry
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Evolution of oxygen and stratification and their relationship in the North Pacific Ocean in CMIP6 Earth system models
Evaluation of CMIP6 model performance in simulating historical biogeochemistry across the southern South China Sea
Drivers of decadal trends in the ocean carbon sink in the past, present, and future in Earth system models
Anthropogenic carbon storage and its decadal changes in the Atlantic between 1990–2020
Ocean alkalinity enhancement impacts: regrowth of marine microalgae in alkaline mineral concentrations simulating the initial concentrations after ship-based dispersions
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Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump
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Reconstructing ocean carbon storage with CMIP6 Earth system models and synthetic Argo observations
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The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle
Model estimates of metazoans' contributions to the biological carbon pump
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Nitrite cycling in the primary nitrite maxima of the eastern tropical North Pacific
Hotspots and drivers of compound marine heatwaves and low net primary production extremes
Ecosystem impacts of marine heat waves in the northeast Pacific
Tracing the role of Arctic shelf processes in Si and N cycling and export through the Fram Strait: insights from combined silicon and nitrate isotopes
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The response of diazotrophs to nutrient amendment in the South China Sea and western North Pacific
Influence of GEOTRACES data distribution and misfit function choice on objective parameter retrieval in a marine zinc cycle model
Physiological flexibility of phytoplankton impacts modelled chlorophyll and primary production across the North Pacific Ocean
Observation-constrained estimates of the global ocean carbon sink from Earth system models
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise)
Controlling factors on the global distribution of a representative marine non-cyanobacterial diazotroph phylotype (Gamma A)
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Global nutrient cycling by commercially targeted marine fish
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.
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
EGUsphere, https://doi.org/10.5194/egusphere-2024-1388, https://doi.org/10.5194/egusphere-2024-1388, 2024
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The study evaluated CO2-carbonate system dynamics in the North Atlantic Subpolar Gyre from 2009 to 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.
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.
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.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
Biogeosciences, 19, 5807–5835, https://doi.org/10.5194/bg-19-5807-2022, https://doi.org/10.5194/bg-19-5807-2022, 2022
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Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Abigale M. Wyatt, Laure Resplandy, and Adrian Marchetti
Biogeosciences, 19, 5689–5705, https://doi.org/10.5194/bg-19-5689-2022, https://doi.org/10.5194/bg-19-5689-2022, 2022
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Marine heat waves (MHWs) are a frequent event in the northeast Pacific, with a large impact on the region's ecosystems. Large phytoplankton in the North Pacific Transition Zone are greatly affected by decreased nutrients, with less of an impact in the Alaskan Gyre. For small phytoplankton, MHWs increase the spring small phytoplankton population in both regions thanks to reduced light limitation. In both zones, this results in a significant decrease in the ratio of large to small phytoplankton.
Margot C. F. Debyser, Laetitia Pichevin, Robyn E. Tuerena, Paul A. Dodd, Antonia Doncila, and Raja S. Ganeshram
Biogeosciences, 19, 5499–5520, https://doi.org/10.5194/bg-19-5499-2022, https://doi.org/10.5194/bg-19-5499-2022, 2022
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We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.
Emily J. Zakem, Barbara Bayer, Wei Qin, Alyson E. Santoro, Yao Zhang, and Naomi M. Levine
Biogeosciences, 19, 5401–5418, https://doi.org/10.5194/bg-19-5401-2022, https://doi.org/10.5194/bg-19-5401-2022, 2022
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We use a microbial ecosystem model to quantitatively explain the mechanisms controlling observed relative abundances and nitrification rates of ammonia- and nitrite-oxidizing microorganisms in the ocean. We also estimate how much global carbon fixation can be associated with chemoautotrophic nitrification. Our results improve our understanding of the controls on nitrification, laying the groundwork for more accurate predictions in global climate models.
Zuozhu Wen, Thomas J. Browning, Rongbo Dai, Wenwei Wu, Weiying Li, Xiaohua Hu, Wenfang Lin, Lifang Wang, Xin Liu, Zhimian Cao, Haizheng Hong, and Dalin Shi
Biogeosciences, 19, 5237–5250, https://doi.org/10.5194/bg-19-5237-2022, https://doi.org/10.5194/bg-19-5237-2022, 2022
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Fe and P are key factors controlling the biogeography and activity of marine N2-fixing microorganisms. We found lower abundance and activity of N2 fixers in the northern South China Sea than around the western boundary of the North Pacific, and N2 fixation rates switched from Fe–P co-limitation to P limitation. We hypothesize the Fe supply rates and Fe utilization strategies of each N2 fixer are important in regulating spatial variability in community structure across the study area.
Claudia Eisenring, Sophy E. Oliver, Samar Khatiwala, and Gregory F. de Souza
Biogeosciences, 19, 5079–5106, https://doi.org/10.5194/bg-19-5079-2022, https://doi.org/10.5194/bg-19-5079-2022, 2022
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Given the sparsity of observational constraints on micronutrients such as zinc (Zn), we assess the sensitivities of a framework for objective parameter optimisation in an oceanic Zn cycling model. Our ensemble of optimisations towards synthetic data with varying kinds of uncertainty shows that deficiencies related to model complexity and the choice of the misfit function generally have a greater impact on the retrieval of model Zn uptake behaviour than does the limitation of data coverage.
Yoshikazu Sasai, Sherwood Lan Smith, Eko Siswanto, Hideharu Sasaki, and Masami Nonaka
Biogeosciences, 19, 4865–4882, https://doi.org/10.5194/bg-19-4865-2022, https://doi.org/10.5194/bg-19-4865-2022, 2022
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We have investigated the adaptive response of phytoplankton growth to changing light, nutrients, and temperature over the North Pacific using two physical-biological models. We compare modeled chlorophyll and primary production from an inflexible control model (InFlexPFT), which assumes fixed carbon (C):nitrogen (N):chlorophyll (Chl) ratios, to a recently developed flexible phytoplankton functional type model (FlexPFT), which incorporates photoacclimation and variable C:N:Chl ratios.
Jens Terhaar, Thomas L. Frölicher, and Fortunat Joos
Biogeosciences, 19, 4431–4457, https://doi.org/10.5194/bg-19-4431-2022, https://doi.org/10.5194/bg-19-4431-2022, 2022
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Estimates of the ocean sink of anthropogenic carbon vary across various approaches. We show that the global ocean carbon sink can be estimated by three parameters, two of which approximate the ocean ventilation in the Southern Ocean and the North Atlantic, and one of which approximates the chemical capacity of the ocean to take up carbon. With observations of these parameters, we estimate that the global ocean carbon sink is 10 % larger than previously assumed, and we cut uncertainties in half.
Natasha René van Horsten, Hélène Planquette, Géraldine Sarthou, Thomas James Ryan-Keogh, Nolwenn Lemaitre, Thato Nicholas Mtshali, Alakendra Roychoudhury, and Eva Bucciarelli
Biogeosciences, 19, 3209–3224, https://doi.org/10.5194/bg-19-3209-2022, https://doi.org/10.5194/bg-19-3209-2022, 2022
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The remineralisation proxy, barite, was measured along 30°E in the southern Indian Ocean during early austral winter. To our knowledge this is the first reported Southern Ocean winter study. Concentrations throughout the water column were comparable to observations during spring to autumn. By linking satellite primary production to this proxy a possible annual timescale is proposed. These findings also suggest possible carbon remineralisation from satellite data on a basin scale.
Zhibo Shao and Ya-Wei Luo
Biogeosciences, 19, 2939–2952, https://doi.org/10.5194/bg-19-2939-2022, https://doi.org/10.5194/bg-19-2939-2022, 2022
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Non-cyanobacterial diazotrophs (NCDs) may be an important player in fixing N2 in the ocean. By conducting meta-analyses, we found that a representative marine NCD phylotype, Gamma A, tends to inhabit ocean environments with high productivity, low iron concentration and high light intensity. It also appears to be more abundant inside cyclonic eddies. Our study suggests a niche differentiation of NCDs from cyanobacterial diazotrophs as the latter prefers low-productivity and high-iron oceans.
Coraline Leseurre, Claire Lo Monaco, Gilles Reverdin, Nicolas Metzl, Jonathan Fin, Claude Mignon, and Léa Benito
Biogeosciences, 19, 2599–2625, https://doi.org/10.5194/bg-19-2599-2022, https://doi.org/10.5194/bg-19-2599-2022, 2022
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Decadal trends of fugacity of CO2 (fCO2), total alkalinity (AT), total carbon (CT) and pH in surface waters are investigated in different domains of the southern Indian Ocean (45°S–57°S) from ongoing and station observations regularly conducted in summer over the period 1998–2019. The fCO2 increase and pH decrease are mainly driven by anthropogenic CO2 estimated just below the summer mixed layer, as well as by a warming south of the polar front or in the fertilized waters near Kerguelen Island.
Priscilla Le Mézo, Jérôme Guiet, Kim Scherrer, Daniele Bianchi, and Eric Galbraith
Biogeosciences, 19, 2537–2555, https://doi.org/10.5194/bg-19-2537-2022, https://doi.org/10.5194/bg-19-2537-2022, 2022
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This study quantifies the role of commercially targeted fish biomass in the cycling of three important nutrients (N, P, and Fe), relative to nutrients otherwise available in water and to nutrients required by primary producers, and the impact of fishing. We use a model of commercially targeted fish biomass constrained by fish catch and stock assessment data to assess the contributions of fish at the global scale, at the time of the global peak catch and prior to industrial fishing.
Cited articles
Acharya, S. S. and Panigrahi, M. K.: Eastward shift and maintenance of
Arabian Sea oxygen minimum zone: Understanding the paradox, Deep-Sea
Res. Pt. I, 115, 240–252, 2016.
Agnihotri, R., Bhattacharya, S. K., Sarin, M. M., and Somayajulu, B. L. K.:
Changes in surface productivity and subsurface denitrification during the
Holocene: a multiproxy study from the eastern Arabian Sea, The Holocene, 13,
701–713, 2003.
Al Azhar, M., Lachkar, Z., Lévy, M., and Smith, S.: Oxygen Minimum Zone
Contrasts Between the Arabian Sea and the Bay of Bengal Implied by
Differences in Remineralization Depth, Geophys. Res. Lett., 44,
11106–111114, 2017.
Al-Azri, A. R., Al-Hashmi, K. A., Al-Habsi, H., Al-Azri, N., and
Al-Khusaibi, S.: Abundance of harmful algal blooms in the coastal waters of
Oman: 2006–2011, Aquat. Ecosyst. Health, 18, 269–281,
2015.
Al-Hashmi, K. A., Smith, S. L., Claereboudt, M., Piontkovski, S. A., and
Al-Azri, A.: Dynamics of potentially harmful phytoplankton in a
semi-enclosed bay in the Sea of Oman, B. Mar. Sci.e, 91,
141–166, 2015.
Altabet, M. A.: Isotopic Tracers of the Marine Nitrogen Cycle: Present and
Past, in: Marine Organic Matter: Biomarkers, Isotopes and DNA, The Handbook
of Environmental Chemistry, edited by: Volkman, J. K., Springer, Berlin,
Heidelberg, 2006.
Altabet, M. A., Francois, R., Murray, D. W., and Prell, W. L.:
Climate-related variations in denitrification in the Arabian Sea from
sediment 15N ∕ 14N ratios, Nature, 373, 506–509, 1995.
Altabet, M. A., Murray, D. W., and Prell, W. L.: Climatically linked
oscillations in Arabian Sea denitrification over the past 1 m.y.:
Implications for the marine N cycle, Paleoceanography, 14, 732–743, 1999.
Altabet, M. A., Higginson, M. J., and Murray, D. W.: The effect of
millennial-scale changes in Arabian Sea denitrification on atmospheric
CO2, Nature, 415, 159–162, 2002.
Altieri, A. H., Harrison, S. B., Seemann, J., Collin, R., Diaz, R. J., and
Knowlton, N.: Tropical dead zones and mass mortalities on coral reefs,
P. Natl. Acad. Sci., 114, 3660, https://doi.org/10.1073/pnas.1621517114, 2017.
Andersson, J. H., Woulds, C., Schwartz, M., Cowie, G. L., Levin, L. A., Soetaert, K., and Middelburg, J. J.: Short-term fate of phytodetritus in sediments across the Arabian Sea Oxygen Minimum Zone, Biogeosciences, 5, 43–53, https://doi.org/10.5194/bg-5-43-2008, 2008.
Antoine, D., André, J.-M., and Morel, A.: Oceanic primary production –
2. Estimation at global scale from satellite (coastal zone color scanner)
chlorophyll, Global Biogeochem. Cy., 10, 57–69, 1996.
Armstrong, R. A., Lee, C., Hedges, J. I., Honjo, S., and Wakeham, S.: A new,
mechanistic model for organic carbon fluxes in the ocean: based on the
quantitative association of POC with ballast minerals, Deep-Sea Res.,
49, 219–236, 2002.
Aumont, O., Maier-Reimer, E., Blain, S., and Monfray, P.: An ecosystem model
of the global ocean including Fe, Si, P colimitations, Global Biogeochem.
Cy., 17, 1060, https://doi.org/10.1029/2001GB001745, 2003.
Aumont, O., Ethé, C., Tagliabue, A., Bopp, L., and Gehlen, M.: PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies, Geosci. Model Dev., 8, 2465–2513, https://doi.org/10.5194/gmd-8-2465-2015, 2015.
Aumont, O., Maury, O., Lefort, S., and Bopp, L.: Evaluating the Potential
Impacts of the Diurnal Vertical Migration by Marine Organisms on Marine
Biogeochemistry, Global Biogeochem. Cy., 32, 1622–1643, 2018.
Babbin, A. R., Keil, R. G., Devol, A. H., and Ward, B. B.: Organic Matter
Stoichiometry, Flux, and Oxygen Control Nitrogen Loss in the Ocean, Science,
344, 406–408, 2014.
Bahl, A., Gnanadesikan, A., and Pradal, M. A.: Variations in Ocean
Deoxygenation Across Earth System Models: Isolating the Role of
Parameterized Lateral Mixing, Global Biogeochem. Cy., 33, 703–724,
2019.
Bange, H. W., Rixen, T., Johansen, A. M., Siefert, R. L., Ramesh, R.,
Ittekkot, V., Hoffmann, M. R., and Andreae, M. O.: A revised nitrogen budget
for the Arabian Sea, Global Biogeochem. Cy., 14, 1283–1297, 2000.
Banse, K.: New views on the degradation and disposition of organic particles
as collected by sediment traps in the open sea, Deep-Sea Res., 37,
1177–1195, 1990.
Banse, K.: Grazing and Zooplankton Production as Key Controls of
Phytoplankton Production in the Open Ocean, Oceanography, 7, 13–20, 1994.
Banse, K., Naqvi, S. W. A., Narvekar, P. V., Postel, J. R., and Jayakumar, D. A.: Oxygen minimum zone of the open Arabian Sea: variability of oxygen and nitrite from daily to decadal timescales, Biogeosciences, 11, 2237–2261, https://doi.org/10.5194/bg-11-2237-2014, 2014.
Bauer, S., Hitchcock, G. L., and Olson, D. B.: Influence of
monsoonally-forced Ekman dynamics upon surface layer depth and plankton
biomass distribution in the Arabian Sea, Deep-Sea Res., 38, 531–553,
1991.
Behrenfeld, M. J. and Falkowski, P. G.: Photosynthetic rates derived from
satellite-based chlorophyll concentration, Limnol. Oceanogr., 42,
1–20, 1997.
Bettencourt, J. H., López, C., Hernández-García, E., Montes,
I., Sudre, J., Dewitte, B., Paulmier, A., and Garçon, V.: Boundaries of
the Peruvian oxygen minimum zone shaped by coherent mesoscale dynamics,
Nat. Geosci., 8, 937–940, 2015.
Bianchi, D., Galbraith, E. D., Carozza, D. A., Mislan, K. A. S., and Stock,
C. A.: Intensification of open-ocean oxygen depletion by vertically
migrating animals, Nat. Geosci., 6, 545–548, 2013.
Bianchi, D., Weber, T. S., Kiko, R., and Deutsch, C.: Global niche of marine
anaerobic metabolisms expanded by particle microenvironments, Nat.
Geosci., 11, 263–268, 2018.
Billett, D. S. M., Bett, B. J., Jacobs, C. L., Rouse, I. P., and Wigham, B.
D.: Mass deposition of jellyfish in the deep Arabian Sea, Limnol.d
Oceanogr., 51, 2077–2083, 2006.
Böll, A., Schulz, H., Munz, P., Rixen, T., Gaye, B., and Emeis, K.-C.:
Contrasting sea surface temperature of summer and winter monsoon variability
in the northern Arabian Sea over the last 25 ka, Palaeogeogr.
Palaeocl., 426, 10–21, 2015.
Böning, P. and Bard, E.: Millenial/centennial-scale thermocline
ventilation changes in the Indian Ocean as reflected by aragonite
preservation and geochemical variations in the Arabian Sea sediments,
Geochim. Cosmochim. Ac., 73, 6771–6788, 2009.
Bopp, L., Resplandy, L., Orr, J. C., Doney, S. C., Dunne, J. P., Gehlen, M., Halloran, P., Heinze, C., Ilyina, T., Séférian, R., Tjiputra, J., and Vichi, M.: Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models, Biogeosciences, 10, 6225–6245, https://doi.org/10.5194/bg-10-6225-2013, 2013.
Bopp, L., Resplandy, L., Untersee, A., Le Mezo, P., and Kageyama, M.: Ocean
(de)oxygenation from the Last Glacial Maximum to the twenty-first century:
insights from Earth System models, Philos. Trans. Roy.
Soc. A, 375, 20160323, https://doi.org/10.5194/bg-10-6225-2013,
2017.
Böttger-Schnack, R.: Vertical structure of small metazoan plankton,
especially noncalanoid copepods, I. Deep Arabian Sea, J. Plank.
Res., 18, 1073–1101, 1996.
Bourbonnais, A., Altabet, M. A., Charoenpong, C. N., Larkum, J., Hu, H.,
Bange, H. W., and Stramma, L.: N-loss isotope effects in the Peru oxygen
minimum zone studied using a mesoscale eddy as a natural tracer experiment,
Global Biogeochem. Cy., 29, 793–811, 2015.
Boyer, T. P., Antonov, J. I., Baranova, O. K., Coleman, C., Garcia, H. E.,
Grodsky, A., Johnson, D. R., Locarnini, R. A., Mishonov, A. V., O'Brien, T.
D., Paver, C. R., Reagan, J. R., Seidov, D., Smolyar, I. V., and Zweng, M.
M.: World Ocean Database 2013, Silver Spring, MD, NOAA Printing Officce, (NOAA Atlas NESDIS, 72), 208 pp., available at: http://hdl.handle.net/11329/357 (last access: 21 January 2018), 2013.
Brandes, J. A., Devol, A. H., Yoshinari, T., Jayakumar, A., and Naqvi, S. W.
A.: Isotopic composition of nitrate in the central Arabian Sea and eastern
tropical North Pacific: A tracer for mixing and nitrogen cycles, Limnol.
Oceanogr., 43, 1680–1689, 1998.
Brandt, P., Hormann, V., Körtzinger, A., Visbeck, M., Krahmann, G.,
Stramma, L., Lumpkin, R., and Schmid, C.: Changes in the ventilation of the
oxygen minimum zone of the tropical North Atlantic, J. Phys.
Oceanogr., 40, 1784–1801, 2010.
Brandt, P., Bange, H. W., Banyte, D., Dengler, M., Didwischus, S.-H., Fischer, T., Greatbatch, R. J., Hahn, J., Kanzow, T., Karstensen, J., Körtzinger, A., Krahmann, G., Schmidtko, S., Stramma, L., Tanhua, T., and Visbeck, M.: On the role of circulation and mixing in the ventilation of oxygen minimum zones with a focus on the eastern tropical North Atlantic, Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, 2015.
Breitburg, D., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P.,
Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K.,
Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W. A., Pitcher, G. C.,
Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M.,
Yasuhara, M., and Zhang, J.: Declining oxygen in the global ocean and
coastal waters, Science, 359, eaam7240, https://doi.org/10.1126/science.aam7240, 2018.
Bristow, L. A., Dalsgaard, T., Tiano, L., Mills, D. B., Bertagnolli, A. D.,
Wright, J. J., Hallam, S. J., Ulloa, O., Canfield, D. E., Revsbech, N. P.,
and Thamdrup, B.: Ammonium and nitrite oxidation at nanomolar oxygen
concentrations in oxygen minimum zone waters, P. Natl.
Acad. Sci., 113, 10601, https://doi.org/10.1073/pnas.1600359113, 2016.
Bristow, L. A., Callbeck, C. M., Larsen, M., Altabet, M. A., Dekaezemacker,
J., Forth, M., Gauns, M., Glud, R. N., Kuypers, M. M. M., Lavik, G.,
Milucka, J., Naqvi, S. W. A., Pratihary, A., Revsbech, N. P., Thamdrup, B.,
Treusch, A. H., and Canfield, D. E.: N2 production rates limited by nitrite
availability in the Bay of Bengal oxygen minimum zone, Nat. Geosci.,
10, 24–29, 2017.
Brock, J. C., McClain, C. R., Luther, M. E., and Hay, W. W.: The
Phytplankton Bloom in the Northwestern Arabian Sea During the Southwest
Monsoon of 1979, J. Geophys. Res., 96, 20623–20642, 1991.
Brock, J. C., McClain, C. R., and Hay, W. W.: A Southwest Monsoon
Hydrographic Climatology for the Northwestern Arabian Sea, Journal of
Geophysical Research, 97, 9455-9465, 1992.
Brocks, J. J., Jarrett, A. J. M., Sirantoine, E., Hallmann, C., Hoshino, Y.,
and Liyanage, T.: The rise of algae in Cryogenian oceans and the emergence
of animals, Nature, 548, 578–581, https://doi.org/10.1038/nature23457, 2017.
Broecker, W. S. and Peng, T.-H.: Tracers in the sea, Lamont-Doherty
Geological Observatory, Columbia University, Palisades, New York, 690 pp., 1982.
Bruce, J. G.: Some details of upwelling off the Somali and Arabian Coasts,
J. Mar. Res., 32, 419–423, 1974.
Burd, A. B., Hansell, D. A., Steinberg, D. K., Anderson, T. R., Arístegui, J., Baltar, F., Beaupré, S. R., Buesseler,
K. O., DeHairs, F., Jackson, G. A., Kadko, D. C., Koppelmann, R., Lampitt,
R. S., Nagata, T., Reinthaler, T., Robinson, C., Robison, B. H., Tamburini,
C., and Tanaka, T.: Assessing the apparent imbalance between geochemical and
biochemical indicators of meso- and bathypelagic biological activity: What
the @$,ôØ! is wrong with present calculations of
carbon budgets?, Deep-Sea Res. Pt. II,
57, 1557–1571, 2010.
Burdanowitz, N., Gaye, B., Hilbig, L., Lahajnar, N., Lückge, A., Rixen,
T., and Emeis, K.-C.: Holocene monsoon and sea level-related changes of
sedimentation in the northeastern Arabian Sea, Deep-Sea Res. Pt. II, 166, 6–18, https://doi.org/10.1016/j.dsr2.2019.03.003, 2019.
Cabré, A., Marinov, I., Bernardello, R., and Bianchi, D.: Oxygen minimum zones in the tropical Pacific across CMIP5 models: mean state differences and climate change trends, Biogeosciences, 12, 5429–5454, https://doi.org/10.5194/bg-12-5429-2015, 2015.
Canfield, D.: Oxygen, a four billion year history, Princeton University
Press, Prniceton, New Jersey, USA, 2014.
Canfield, D. E., Kraft, B., Löscher, C. R., Boyle, R. A., Thamdrup, B.,
and Stewart, F. J.: The regulation of oxygen to low concentrations in marine
oxygen-minimum zones, J. Mar. Res., 77, 297–324, 2019.
Carruthers, J. N., Gogate, S. S., Naidu, J. R., and Laevastu, T.: Shorewards
Upslope of the Layer of Minimum Oxygen Off Bombay: Its Influence on Marine
Biology, Especially Fisheries, Nature, 183, 1084–1087, 1959.
Cavan, E. L., Trimmer, M., Shelley, F., and Sanders, R.: Remineralization of
particulate organic carbon in an ocean oxygen minimum zone, Nat.
Commun., 8, 14847, https://doi.org/10.1038/ncomms14847, 2017.
Chelton, D. B., Gaube, P., Schlax, M. G., Early, J. J., and Samelson, R. M.:
The Influence of Nonlinear Mesoscale Eddies on Near-Surface Oceanic
Chlorophyll, Science, 334, 328, https://doi.org/10.1126/science.1208897, 2011.
Chen, G., Wang, D., and Hou, Y.: The features and interannual variability
mechanism of mesoscale eddies in the Bay of Bengal, Cont. Shelf
Res., 47, 178–185, 2012.
Cline, J. D. and Kaplan, I. R.: Isotopic fractionation of dissolved nitrate
during denitrification in the eastern tropical north pacific ocean, Mar.e
Chem., 3, 271–299, 1975.
Cocco, V., Joos, F., Steinacher, M., Frölicher, T. L., Bopp, L., Dunne, J., Gehlen, M., Heinze, C., Orr, J., Oschlies, A., Schneider, B., Segschneider, J., and Tjiputra, J.: Oxygen and indicators of stress for marine life in multi-model global warming projections, Biogeosciences, 10, 1849–1868, https://doi.org/10.5194/bg-10-1849-2013, 2013.
Contreras-Rosales, L. A., Schefuß, E., Meyer, V., Palamenghi, L.,
Lückge, A., and Jennerjahn, T. C.: Origin and fate of sedimentary
organic matter in the northern Bay of Bengal during the last 18 ka, Glob.
Planet. Change, 146, 53–66, 2016.
Couespel, D., Lévy, M., and Bopp, L.: Major Contribution of Reduced
Upper Ocean Oxygen Mixing to Global Ocean Deoxygenation in an Earth System
Model, Geophys. Res. Lett., 46, 12239–12249, 2019.
Cowie, G.: The biogeochemistry of Arabian Sea surficial sediments: A review
of recent studies, Prog. Oceanogr., 65, 260–289, 2005.
Cowie, G. L., Calvert, S. E., Pedersen, T. F., Schulz, H., and von Rad, U.:
Organic content and preservational controls in surficial shelf and slope
sediments from the Arabian Sea (Pakistan margin), Mar. Geol., 161,
23–38, 1999.
Cowie, G. L. and Levin, L. A.: Benthic biological and biogeochemical
patterns and processes across an oxygen minimum zone (Pakistan margin, NE
Arabian Sea), Deep-Sea Res. Pt. II,
56, 261–270, 2009.
Cowie, G. L., Mowbray, S., Lewis, M., Matheson, H., and McKenzie, R.: Carbon
and nitrogen elemental and stable isotopic compositions of surficial
sediments from the Pakistan margin of the Arabian Sea, Deep-Sea Res.
Pt. II, 56, 271–282, 2009.
Crusius, J., Calvert, S., Pedersen, T., and Sage, D.: Rhenium and molybdenum
enrichments in sediments as indicators of oxic, suboxic and sulfidic
conditions of deposition, Earth Planet. Sc. Lett., 145, 65–78,
1996.
Currie, R. I., Fisher, A. E., and Hargreaves, P. M.: Arabian Sea Upwelling.
in: Biology of the Indian Ocean, edited by: Zeitschel, B., Ecological Studies 3,
Springer Verlag, Berlin, 1973.
d'Ovidio, F., De Monte, S., Penna, A. D., Cotté, C., and Guinet, C.:
Ecological implications of eddy retention in the open ocean: a Lagrangian
approach, J. Phys. A, 46, 254023, https://doi.org/10.1088/1751-8113/46/25/254023,
2013.
Dalsgaard, T., Canfield, D. E., Petersen, J., Thamdrup, B., and
Acuna-Gonzalez, J.: N2 production by the anammox reaction in the anoxic
water column of Golfo Dulce, Costa Rica, Nature, 422, 606–608, 2003.
Dalsgaard, T., Stewart, F. J., Thamdrup, B., De Brabandere, L., Revsbech, N.
P., Ulloa, O., Canfield, D. E., and DeLong, E. F.: Oxygen at Nanomolar
Levels Reversibly Suppresses Process Rates and Gene Expression in Anammox
and Denitrification in the Oxygen Minimum Zone off Northern Chile, mBio, 5,
e01966-01914, https://doi.org/10.1128/mBio.01966-14, 2014.
Das, M., Singh, R. K., Gupta, A. K., and Bhaumik, A. K.: Holocene
strengthening of the Oxygen Minimum Zone in the northwestern Arabian Sea
linked to changes in intermediate water circulation or Indian monsoon
intensity?, Paleogeogr. Paleoclimatol., 483, 125–135, 2017.
del Giorgio, P. A. and Duarte, C. M.: Respiration in the open ocean, Nature,
420, 379–384, 2002.
Deuser, W. G., Ross, E. H., and Mlodzinska, Z. J.: Evidence for and rate of
denitrification in the Arabian Sea, Deep-Sea Res., 25, 431–445, 1978.
Diaz, R. J. and Rosenberg, R.: Spreading Dead Zones and Consequences for
Marine Ecosystems, Science, 321, 926–929, 2008.
Diaz, R. J., Rosenberg, R., and Sturdivant, K.: Hypoxia in estuaries and
semi-enclosed seas, in: Ocean deoxygenation: Everyone's problem, edited by: Laffoley,
D. and Baxter, J. M., IUCN, Gland, Switzerland 2019.
Dietrich, G.: Aufbau und Bewegung von Golfstrom und Agulhasstrom,
Naturwissenschaften, 24, 225–230, 1936.
Duteil, O., Koeve, W., Oschlies, A., Aumont, O., Bianchi, D., Bopp, L., Galbraith, E., Matear, R., Moore, J. K., Sarmiento, J. L., and Segschneider, J.: Preformed and regenerated phosphate in ocean general circulation models: can right total concentrations be wrong?, Biogeosciences, 9, 1797–1807, https://doi.org/10.5194/bg-9-1797-2012, 2012.
Ekau, W., Auel, H., Pörtner, H.-O., and Gilbert, D.: Impacts of hypoxia on the structure and processes in pelagic communities (zooplankton, macro-invertebrates and fish), Biogeosciences, 7, 1669–1699, https://doi.org/10.5194/bg-7-1669-2010, 2010.
Emerson, S.: Annual net community production and the biological carbon flux
in the ocean, Global Biogeochem. Cy., 28, 14–28, 2014.
Eppley, R. W. and Peterson, B. J.: Particulate organic matter flux and
planktonic new production in the deep ocean, Nature, 282, 677–680, 1979.
Escribano, R.: Zooplankton interactions with the oxygen minimum zone in the
eastern south pacific, Gayana (Concepción), 70, 19–21, 2006.
Eugster, O. and Gruber, N.: A probabilistic estimate of global marine
N-fixation and denitrification, Global Biogeochem. Cy., 26, GB4013, https://doi.org/10.1029/2012GB004300, 2012.
Falkowski, P. G., Katz, M. E., Knoll, A. H., Quigg, A., Raven, J. A.,
Schofield, O., and Taylor, F. J. R.: The Evolution of Modern Eukaryotic
Phytoplankton, Science, 305, 354–360, 2004.
Fassbender, A. J., Bourbonnais, A., Clayton, S., Gaube, P., Omand, M.,
Franks, P. J. S., Altabet, M. A., and McGillicuddy Jr., D. J.: Interpreting
mosaics of ocean biogeochemistry, EOS, 99, https://doi.org/10.1029/2018EO109707, 2018.
Fiedler, B., Grundle, D. S., Schütte, F., Karstensen, J., Löscher, C. R., Hauss, H., Wagner, H., Loginova, A., Kiko, R., Silva, P., Tanhua, T., and Körtzinger, A.: Oxygen utilization and downward carbon flux in an oxygen-depleted eddy in the eastern tropical North Atlantic, Biogeosciences, 13, 5633–5647, https://doi.org/10.5194/bg-13-5633-2016, 2016.
Filippelli, G. and Cowie, G.: Carbon and Phosphorus Cycling in Arabian Sea
Sediments across the Oxygen Minimum Zone, J. Oceanogr. Mar.e
Res., 5, 171, https://doi.org/10.4172/2572-3103.1000171, 2017.
Fu, W., Primeau, F., Keith Moore, J., Lindsay, K., and Randerson, J. T.:
Reversal of Increasing Tropical Ocean Hypoxia Trends With Sustained Climate
Warming, Global Biogeochem. Cy., 32, 551–564, 2018.
Ganeshram, R. S., Pedersen, T. F., Calvert, S. E., and Murray, J. W.: Large
changes in oceanic nutrient inventories from glacial to interglacial
periods, Nature, 376, 755–758, 1995.
Garcia, H. E., Locarnini, R. A., Boyer, T. P., Antonov, J. I., Zweng, M. M.,
Baranova, O. K., and Johnson, D. R.: World Ocean Atlas 2009, in: NOAA Atlas
NESDIS 71, edited by: Levitus, S., U.S. Government Printing Office, Washington,
D.C., 2010.
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, Vol. 3, Dissolved Oxygen, Apparent Oxygen Utilization, and Oxygen Saturation, edited by: S. Levitus, A. Mishonov Technical Ed., NOAA Atlas NESDIS 75, 27 pp., 2014.
Garrison, D. L., Gowing, M. M., and Hughes, M. P.: Nano- and microplankton
in the northern Arabian Sea during the Southwest Monsoon, August-September
1995 A US-JGOFS study, Deep-Sea Res. Pt. II, 45, 2269–2299, 1998.
Garrison, D. L., Gowing, M. M., Hughes, M. P., Campbell, L., Caron, D. A.,
Dennett, M. R., Shalapyonok, A., Olson, R. J., Landry, M. R., and Brown, S.
L.: Microbial food web structure in the Arabian Sea: a US JGOFS study, Deep-Sea Res. Pt. II, 47, 1387–1422, 2000.
Gaye, B., Nagel, B., Dähnke, K., Rixen, T., and Emeis, K.-C.: Evidence
of parallel denitrification and nitrite oxidation in the ODZ of the Arabian
Sea from paired stable isotopes of nitrate and nitrite, Global
Biogeochem. Cy., 27, GB004115, https://doi.org/10.1002/2011gb004115, 2013.
Gaye, B., Böll, A., Segschneider, J., Burdanowitz, N., Emeis, K.-C., Ramaswamy, V., Lahajnar, N., Lückge, A., and Rixen, T.: Glacial–interglacial changes and Holocene variations in Arabian Sea denitrification, Biogeosciences, 15, 507–527, https://doi.org/10.5194/bg-15-507-2018, 2018.
Gaye-Haake, B., Lahajnar, N., Emeis, K.-C., Unger, D., Rixen, T., Suthhof,
A., Ramaswamy, V., Schulz, H., Paropkari, A. L., Guptha, M. V. S., and
Ittekkot, V.: Stable nitrogen isotopic ratios of sinking particles and
sediments from the northern Indian Ocean, Mar. Chem., 96, 243–255,
2005.
Gilson, H. C.: The nitrogen cycle, Scientific Reports John Murray Expedition 1933–1934, Vol. 2, 21–81, 1937.
Gnanadesikan, A., Dunne, J. P., and John, J.: Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model, Biogeosciences, 9, 1159–1172, https://doi.org/10.5194/bg-9-1159-2012, 2012.
Gnanadesikan, A., Bianchi, D., and Pradal, M.-A.: Critical role for
mesoscale eddy diffusion in supplying oxygen to hypoxic ocean waters,
Geophys. Res. Lett., 40, 5194–5198, 2013.
Goes, J. I. and Gomes, H.: An ecosystem in transition: the emergence of
mixotrophy in the Arabian Sea, in: Aquatic Microbial Ecology and
Biogeochemistry: A Dual Perspective, edited by: Glibert, P. and Kana, T.,
Springer International Publishing, p. 245, 2016.
Goes, J. I., Tian, H., Gomes, H. d. R., Anderson, O. R., Al-Hashmi, K.,
deRada, S., Luo, H., Al-Kharusi, L., Al-Azri, A., and Martinson, D. G.:
Ecosystem state change in the Arabian Sea fuelled by the recent loss of snow
over the Himalayan-Tibetan Plateau region, Sci. Rep., 10, 7422, https://doi.org/10.1038/s41598-020-64360-2,
2020.
Gomes, d. R. H., Goes, J. I., Matondkar, S. G. P., Buskey, E. J., Basu, S.,
Parab, S., and Thoppil, P.: Massive outbreaks of Noctiluca scintillans
blooms in the Arabian Sea due to spread of hypoxia, Nat. Commun.,
5, 4862, https://doi.org/10.1038/ncomms5862, 2014.
Gomes, H., Goes, J. I., Matondkar, S. G. P., Parab, S. G., Al-Azri, A., and
Thoppil, P. G.: Unusual Blooms of the Green Noctiluca Miliaris (Dinophyceae) in the Arabian
Sea during the Winter Monsoon, in: Indian Ocean: Biogeochemical Processes
and Ecological Variability, edited by: Wiggert, J. D., Hood, R. R., Naqvi, S. W. A.,
Smith, S. L., and Brink, K. H., AGU Book Series, American Geophysical
Union, 2009.
Gonzalez, R. R. and Quiñones, R. A.: Ldh activity in Euphausia mucronata
and Calanus chilensis: implications for vertical migration behaviour,
J. Plank. Res., 24, 1349–1356, 2002.
Gooday, A. J., Levin, L. A., Aranda da Silva, A., Bett, B. J., Cowie, G. L.,
Dissard, D., Gage, J. D., Hughes, D. J., Jeffreys, R., Lamont, P. A.,
Larkin, K. E., Murty, S. J., Schumacher, S., Whitcraft, C., and Woulds, C.:
Faunal responses to oxygen gradients on the Pakistan margin: A comparison of
foraminiferans, macrofauna and megafauna, Deep-Sea Res. Pt. II, 56, 488–502, 2009.
Goswami, S. C., Saparia, J. S., and Bhargava, R. M. S.(Eds.): Zooplankton standing stock
assessment and fishery resources in the Indian seas, Oxford & IBH
Publishing Co., New Delhi, 217–225, 1992.
Gruber, N.: The dynamics of the marine nitrogen cycle and its influence on
atmospheric CO2, in: Carbon-Climate Interactions, edited by: Follows, M. and Oguz, T., NATO ASI Series, New York, 2004.
Gruber, N., Lachkar, Z., Frenzel, H., Marchesiello, P., Munnich, M.,
McWilliams, J. C., Nagai, T., and Plattner, G.-K.: Eddy-induced reduction of
biological production in eastern boundary upwelling systems, Nat. Geosci.,
4, 787–792, 2011.
Gupta, G. V. M., Sudheesh, V., Sudharma, K. V., Saravanane, N., Dhanya, V.,
Dhanya, K. R., Lakshmi, G., Sudhakar, M., and Naqvi, S. W. A.: Evolution to
decay of upwelling and associated biogeochemistry over the southeastern
Arabian Sea shelf, J. Geophys. Res.-Biogeo., 121,
159–175, 2016.
Haake, B. and Ittekkot, V.: Die Wind-getriebene “biologische Pumpe” und der
Kohlenstoffentzug im Ozean, Naturwissenschaften, 77, 75–79, 1990.
Hamm, C. E.: Interactive aggregation and sedimentation of diatoms and
clay-sized lithogenic material, Limnol. Oceanogr., 47, 1790–1795,
2002.
Haq, S. M., Khan, J. A., and Chugtai, S.: The Distribution and Abundance of
Zooplankton along the Coast of Pakistan during Postmonsoon and Premonsoon
Periods, in: The Biology of the Indian Ocean, edited by: Zeitzschel, B. and Gerlach, S.
A., Springer Berlin Heidelberg, Berlin, Heidelberg, 1973.
Harrison, P. J., Piontkovski, S., and Al-Hashmi, K.: Understanding how
physical-biological coupling influences harmful algal blooms, low oxygen and
fish kills in the Sea of Oman and the Western Arabian Sea, Mar. Pollut.
Bull., , 114, 25–34, https://doi.org/10.1016/j.marpolbul.2016.11.008, 2017.
Helly, J. J. and Levin, L. A.: Global distribution of naturally occurring
marine hypoxia on continental margins, Deep-Sea Res. Pt. I, 51, 1159–1168, 2004.
Henschke, N., Everett, J. D., Richardson, A. J., and Suthers, I. M.:
Rethinking the Role of Salps in the Ocean, Trends Ecol. Evol.,
31, 720–733, 2016.
Herring, P. J., Fasham, M. J. R., Weeks, A. R., Hemmings, J. C. P., Roe, H.
S. J., Pugh, P. R., Holley, S., Crisp, N. A., and Angel, M. V.: Across-slope
relations between the biological populations, the euphotic zone and the
oxygen minimum layer off the coast of Oman during the southwest monsoon
(August, 1994), Prog. Oceanogr., 41, 69–109, 1998.
Higginson, M. J., Altabet, M. A., Murray, D. W., Murray, R. W., and Herbert,
T. D.: Geochemical evidence for abrupt changes in relative strength of the
Arabian monsoons during a stadial/interstadial climate transition,
Geochim. Cosmochim. Ac., 68, 3807–3826, 2004.
Himmler, T., Smrzka, D., Zwicker, J., Kasten, S., Shapiro, R. S., Bohrmann,
G., and Peckmann, J.: Stromatolites below the photic zone in the northern
Arabian Sea formed by calcifying chemotrophic microbial mats, Geology, 46,
339–342, 2018.
Hood, R. R., Beckley, L. E., and Wiggert, J. D.: Biogeochemical and
ecological impacts of boundary currents in the Indian Ocean, Prog.
Oceanogr., 156, 290–325, 2017.
Howell, E. A., Doney, S. C., Fine, R. A., and Olson, D. B.: Geochemical
estimates of denitrification in the Arabian Sea and the Bay of Bengal during
WOCE, Geophys. Res. Lett., 24, 2549–2552, 1997.
Hunter, W. R., Levin, L. A., Kitazato, H., and Witte, U.: Macrobenthic assemblage structure and organismal stoichiometry control faunal processing of particulate organic carbon and nitrogen in oxygen minimum zone sediments, Biogeosciences, 9, 993–1006, https://doi.org/10.5194/bg-9-993-2012, 2012.
Hupe, A. and Karstensen, J.: Redfield stoichiometry in Arabian Sea
subsurface waters, Global Biogeochem. Cy., 14, 357–372, 2000.
Ingole, B. S., Sautya, S., Sivadas, S., Singh, R., and Nanajkar, M.:
Macrofaunal community structure in the western Indian continental margin
including the oxygen minimum zone, Mar. Ecol., 31, 148–166, 2010.
Ito, T., Minobe, S., Long, M. C., and Deutsch, C.: Upper ocean O2 trends:
1958–2015, Geophys. Res. Lett., 44, 4214–4223, 2017.
Ittekkot, V.: The abiotically driven biological pump in the ocean and
short-term fluctuations in atmospheric CO2 contents, Glob.
Planet. Change, 8, 17–25, 1993.
Ivanenkov, V. N. and Rozanov, A. G.: Hydrogen sulphide contamination of the
intermediate water layers of the Arabian Sea and the Bay of Bengal,
Okeanologiya, 1, 443–449, 1961.
Ivanochko, T. S., Ganeshram, R. S., Brummer, G.-J. A., Ganssen, G., Jung, S.
J. A., Moreton, S. G., and Kroon, D.: Variations in tropical convection as
an amplifier of global climate change at the millennial scale, Earth
Planet. Sc. Lett., 235, 302–314, 2005.
Jeffreys, R. M., Wolff, G. A., and Cowie, G. L.: Influence of oxygen on
heterotrophic reworking of sedimentary lipids at the Pakistan margin, Deep-Sea Res. Pt. II, 56, 358–375, 2009.
Jeffreys, R. M., Levin, L. A., Lamont, P. A., Woulds, C., Whitcraft, C. R.,
Mendoza, G. F., Wolff, G. A., and Cowie, G. L.: Living on the edge:
single-species dominance at the Pakistan oxygen minimum zone boundary,
Mar. Ecol. Prog. Ser., 470, 79–99, 2012.
Jensen, M. M., Lam, P., Revsbech, N. P., Nagel, B., Gaye, B., Jetten, M. S.
M., and Kuypers, M. M. M.: Intensive nitrogen loss over the Omani Shelf due
to anammox coupled with dissimilatory nitrite reduction to ammonium, ISME J.,
5, 1660–1670, 2011.
Jilbert, T., Slomp, C. P., Gustafsson, B. G., and Boer, W.: Beyond the Fe-P-redox connection: preferential regeneration of phosphorus from organic matter as a key control on Baltic Sea nutrient cycles, Biogeosciences, 8, 1699–1720, https://doi.org/10.5194/bg-8-1699-2011, 2011.
Johnson, K. S., Riser, S. C., and Ravichandran, M.: Oxygen variability
controls denitrification in the bay of Bengal oxygen minimum zone,
Geophys. Res. Lett., 46, 804–811, 2019.
Kalvelage, T., Jensen, M. M., Contreras, S., Revsbech, N. P., Lam, P.,
Günter, M., LaRoche, J., Lavik, G., and Kuypers, M. M. M.: Oxygen
Sensitivity of Anammox and Coupled N-Cycle Processes in Oxygen Minimum
Zones, PLOS ONE, 6, e29299, https://doi.org/10.1371/journal.pone.0029299, 2011.
Karlson, K., Bonsdorff, E., and Rosenberg, R.: The Impact of Benthic
Macrofauna for Nutrient Fluxes from Baltic Sea Sediments, AMBIO, 36, 161–167, 167, 2007.
Karstensen, J., Stramma, L., and Visbeck, M.: Oxygen minimum zones in the
eastern tropical Atlantic and Pacific oceans, Prog. Oceanogr., 77,
331–350, 2008.
Karstensen, J., Schütte, F., Pietri, A., Krahmann, G., Fiedler, B., Grundle, D., Hauss, H., Körtzinger, A., Löscher, C. R., Testor, P., Vieira, N., and Visbeck, M.: Upwelling and isolation in oxygen-depleted anticyclonic modewater eddies and implications for nitrate cycling, Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, 2017.
Keeling, R. F., Körtzinger, A., and Gruber, N.: Ocean Deoxygenation in a
Warming World, Annu. Rev. Mar. Sci., 2, 199–229, 2009.
Kendall, C., Elliott, E. M., and Wankel, S. D.: Tracing anthropogenic inputs
of nitrogen to ecosystems, in: Stable Isotopes in Ecology and Environmental
Science, edited by: Michener, R. H. and Lajtha, K., Blackwell Publshing, 2007.
Kessarkar, P. M., Naqvi, S. W. A., Thamban, M., Fernandes, L. L., Siebert,
C., Rao, V. P., Kawahata, H., Ittekkot, V., and Frank, M.: Variations in
Denitrification and Ventilation Within the Arabian Sea Oxygen Minimum Zone
During the Holocene, Geochem. Geophy. Geosy., 19, 2179–2193,
2018.
Koho, K. A., Nierop, K. G. J., Moodley, L., Middelburg, J. J., Pozzato, L., Soetaert, K., van der Plicht, J., and Reichart, G.-J.: Microbial bioavailability regulates organic matter preservation in marine sediments, Biogeosciences, 10, 1131–1141, https://doi.org/10.5194/bg-10-1131-2013, 2013.
Kraal, P., Slomp, C. P., Reed, D. C., Reichart, G.-J., and Poulton, S. W.: Sedimentary phosphorus and iron cycling in and below the oxygen minimum zone of the northern Arabian Sea, Biogeosciences, 9, 2603–2624, https://doi.org/10.5194/bg-9-2603-2012, 2012.
Kumar, D., M., Naqvi, S. W. A., George, M. D., and Jayakumar, A.: A sink for
atmospheric carbon dioxide in the northeastern Indian Ocean, J.
Geophys. Res., 101, 18121–18125, 1996.
Kumar, S. P., Nuncio, M., Ramaiah, N., Sardesai, S., Narvekar, J.,
Fernandes, V., and Paul, J. T.: Eddy-mediated biological productivity in the
Bay of Bengal during fall and spring intermonsoons, Deep-Sea Res. Pt.
I, 54, 1619–1640, 2007.
Kurian, S., Kessarkar, P. M., Purnachandra Rao, V., Reshma, K., Sarkar, A.,
Pattan, J. N., and Naqvi, S. W. A.: Controls on organic matter distribution
in oxygen minimum zone sediments from the continental slope off western
India, J. Mar. Syst., 207, 103–118, https://doi.org/10.1016/j.jmarsys.2018.09.003, 2018. 103118, 2018.
Kuypers, M. M. M., Sleikers, A. O., Lavik, G., Schmid, M., Jorgensen, B. B.,
Kuenen, J. G., Damsté, J. S. S., Strous, M., and Jetten, M. S. M.:
Anaerobic ammonium oxidation by anammox bacteria in the Black Sea, Nature,
422, 608–611, 2001.
Kwiatkowski, L., Torres, O., Bopp, L., Aumont, O., Chamberlain, M., Christian, J. R., Dunne, J. P., Gehlen, M., Ilyina, T., John, J. G., Lenton, A., Li, H., Lovenduski, N. S., Orr, J. C., Palmieri, J., Santana-Falcón, Y., Schwinger, J., Séférian, R., Stock, C. A., Tagliabue, A., Takano, Y., Tjiputra, J., Toyama, K., Tsujino, H., Watanabe, M., Yamamoto, A., Yool, A., and Ziehn, T.: Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections, Biogeosciences, 17, 3439–3470, https://doi.org/10.5194/bg-17-3439-2020, 2020.
Lachkar, Z., Smith, S., Lévy, M., and Pauluis, O.: Eddies reduce
denitrification and compress habitats in the Arabian Sea, Geophys.
Res. Lett., 43, 9148–9156, 2016.
Lachkar, Z., Lévy, M., and Smith, S.: Intensification and deepening of the Arabian Sea oxygen minimum zone in response to increase in Indian monsoon wind intensity, Biogeosciences, 15, 159–186, https://doi.org/10.5194/bg-15-159-2018, 2018.
Lachkar, Z., Lévy, M., and Smith, K. S.: Strong Intensification of the
Arabian Sea Oxygen Minimum Zone in Response to Arabian Gulf Warming,
Geophys. Res. Lett., 46, 5420–5429, 2019.
Laufkötter, C., John, J. G., Stock, C. A., and Dunne, J. P.: Temperature
and oxygen dependence of the remineralization of organic matter, Global
Biogeochem. Cy., 31, 1038–1050, 2017.
Law, G. T. W., Cowie, G. L., Breuer, E. R., Schwartz, M. C., Martyn Harvey,
S., Woulds, C., Shimmield, T. M., Shimmield, G. B., and Doig, K. A.: Rates
and Regulation of Microbially Mediated Aerobic and Anaerobic Carbon
Oxidation Reactions in Continental Margin Sediments from the Northeastern
Arabian Sea (Pakistan Margin), Indian Ocean Biogeochemical Processes and
Ecological Variability, in: Geophysical Monograph Series, 299–319, https://doi.org/10.1029/2008GM000765,
2009.
Lengger, S. K., Rush, D., Mayser, J. P., Blewett, J., Schwartz-Narbonne, R., Talbot, H. M., Middelburg, J. J., Jetten, M. S. M., Schouten, S., Sinninghe Damsté, J. S., and Pancost, R. D.: Dark carbon fixation in the Arabian Sea oxygen minimum zone contributes to sedimentary organic carbon (SOM), Global Biogeochem. Cy., 33, 1715–1732, https://doi.org/10.1029/2019GB006282, 2019.
Lengger, S., Rush, D., Mayser, J. P., Blewett, J., Schwartz-Narbonne, R.,
Talbot, H., Middelburg, J. J., Jetten, M. S. M., Schouten, S., Sinninghe
Damsté, J. S., and Pancost, R. D.: Dark carbon fixation contributes to
sedimentary organic carbon in the Arabian Sea oxygen minimum zone, Global
Biogeochem. Cy., 33, 1715–1732, https://doi.org/10.1029/2019GB006282, 2020.
Lenton, T. M. and Watson, A. J.: Revolutions that made the Earth, Oxford
University Press, Oxford, 196 pp., 2011.
Levin, L. A., Huggett, C. L., and Wishner, K. F.: Control of deep-sea
benthic community structure by oxygen and organic-matter gradients in the
eastern Pacific Ocean, J. Mar. Res., 49, 763–800, 1991.
Levin, L. A., Ekau, W., Gooday, A. J., Jorissen, F., Middelburg, J. J., Naqvi, S. W. A., Neira, C., Rabalais, N. N., and Zhang, J.: Effects of natural and human-induced hypoxia on coastal benthos, Biogeosciences, 6, 2063–2098, https://doi.org/10.5194/bg-6-2063-2009, 2009a.
Levin, L. A., Whitcraft, C. R., Mendoza, G. F., Gonzalez, J. P., and Cowie,
G.: Oxygen and organic matter thresholds for benthic faunal activity on the
Pakistan margin oxygen minimum zone (700–1100 m), Deep-Sea Res. Pt. II, 56, 449–471, 2009b.
Levin, L. A., Gage, J. D., Martin, C., and Lamont, P. A.: Macrobenthic
community structure within and beneath the oxygen minimum zone, NW Arabian
Sea, Deep-Sea Res. Pt. II, 47,
189–226, 2000.
Longhurst, A. R.: Vertical distribution of zooplankton in relation to the
eastern Pacific oxygen minimum, Deep-Sea Res. Oceanogr.c
Abstract., 14, 51–63, 1967.
Lotliker, A. A., Baliarsingh, S. K., Trainer, V. L., Wells, M. L., Wilson,
C., Udaya Bhaskar, T. V. S., Samanta, A., and Shahimol, S. R.:
Characterization of oceanic Noctiluca blooms not associated with hypoxia in
the Northeastern Arabian Sea, Harmful Algae, 74, 46–57, 2018.
Lucas, C. H., Jones, D. O. B., Hollyhead, C. J., Condon, R. H., Duarte, C.
M., Graham, W. M., Robinson, K. L., Pitt, K. A., Schildhauer, M., and
Regetz, J.: Gelatinous zooplankton biomass in the global oceans: geographic
variation and environmental drivers, Glob. Ecol. Biogeogr., 23,
701–714, 2014.
Lyons, T. W., Reinhard, C. T., and Planavsky, N. J.: The rise of oxygen in
Earth/'s early ocean and atmosphere, Nature, 506, 307–315, 2014.
Mahesh, B. S. and Banakar, V. K.: Change in the intensity of low-salinity
water inflow from the Bay of Bengal into the Eastern Arabian Sea from the
Last Glacial Maximum to the Holocene: Implications for monsoon variations,
Paleogeogr. Paleocl., 397, 31–37, 2014.
Mariotti, A., Germon, J. C., Hubert, P., Kaiser, P., Letolle, R., Tardieux,
A., and Tardieux, P.: Experimental determination of nitrogen kinetic isotope
fractionation: Some principles; illustration for the denitrification and
nitrification processes, Plant Soil, 62, 413–430, 1981.
Martin, B., Koppelmann, R., and Kassatov, P.: Ecological relevance of salps
and doliolids in the northern Benguela Upwelling System, J. Plank.
Res., 39, 290–304, 2017.
McCartney, M. S.: Subantarctic Mode Water, in: A Voyage of Discovery: George
Deacon 70th Anniversary Volume, edited by: Angel, M. V., Supplement to Deep-Sea
Research, Pergamon Press, Oxford, UK, 1977.
McCreary Jr., J. P., Yu, Z., Hood, R. R., Vinaychandran, P. N., Furue, R.,
Ishida, A., and Richards, K. J.: Dynamics of the Indian-Ocean oxygen minimum
zones, Prog. Oceanogr., 112/113, 15–37, 2013.
McElroy, M. B.: Marine biological controls on atmospheric CO2 and
climate, Nature, 302, 328–329, 1983.
McGillicuddy, D. J.: Mechanisms of Physical-Biological-Biogeochemical
Interaction at the Oceanic Mesoscale, Annu. Rev. Mar. Sci.e, 8,
125–159, 2016.
Middelburg, J. J.: Chemoautotrophy in the ocean, Geophys. Res.h
Lett., 38, L24604, https://doi.org/10.1029/2011gl049725, 2011.
Middelburg, J. J. and Levin, L. A.: Coastal hypoxia and sediment biogeochemistry, Biogeosciences, 6, 1273–1293, https://doi.org/10.5194/bg-6-1273-2009, 2009.
Möbius, J., Gaye, B., Lahajnar, N., Bahlmann, E., and Emeis, K.-C.:
Influence of diagenesis on sedimentary 15∘ N in the Arabian Sea over the last
130 kyr, Mar. Geol., 284, 127–138, 2011.
Morcos, S. A. and AbdAllah, A. M.: Oceanography of the Gulf of Aden: John Murray–Mabahiss Expedition 1933–1934 Revisited, Egypt. J. Aquat. Res., 38, 77–91, https://doi.org/10.1016/j.ejar.2012.12.001, 2012.
Naidu, P. D. and Govil, P.: New evidence on the sequence of deglacial
warming in the tropical Indian Ocean, J. Quaternary Sci., 25,
1138–1143, 2010.
Naqvi, S. A. S.: Evidence for ocean deoxygenation and its patterns: Indian
Ocean, in: Ocean deoxygenation: Everyone's problem, edited by: Laffoley, D. and Baxter,
J. M., IUCN, Gland, Switzerland, 2019.
Naqvi, S. W. A. and Shailaja, M. S.: Activity of the respiratory electron
transport system and respiration rates within the oxygen minimum layer of
the Arabian Sea, Deep-Sea Res. Pt. II, 40, 687–695, 1993.
Naqvi, S. W. A., Noronha, R. J., and Reddy, C. V. G.: Denitrification in the
Arabian Sea, Deep-Sea Res., 29, 459–469, 1982.
Naqvi, S. W. A., Yoshinari, T., Jayakumar, A., Altabet, M. A., Narvekar, P.
V., Devol, A. H., Brandes, J. A., and Codispoti, L. A.: Budgetary and
biogeochemical implications of N2O isotope signatures in the Arabian
Sea, Nature, 394, 462–464, 1998.
Naqvi, S. W. A., Jayakumar, D. A., Narvekar, P. V., Naik, H., Sarma, V. V.
S. S., D'Souza, W., Joseph, S., and George, M. D.: Increased marine
production of N2O due to intensifying anoxia on the Indian continental
shelf, Nature, 408, 346–349, 2000.
Naqvi, S. W. A., Moffett, J. W., Gauns, M. U., Narvekar, P. V., Pratihary, A. K., Naik, H., Shenoy, D. M., Jayakumar, D. A., Goepfert, T. J., Patra, P. K., Al-Azri, A., and Ahmed, S. I.: The Arabian Sea as a high-nutrient, low-chlorophyll region during the late Southwest Monsoon, Biogeosciences, 7, 2091–2100, https://doi.org/10.5194/bg-7-2091-2010, 2010.
Naqvi, W. A.: Geographical extent of denitrification in the Arabian Sea in
relation to some physical processes, Oceanol. Ac., 14, 281–290, 1991.
Olson, D. B., Hitchcock, G. L., Fine, R. A., and Warren, B. A.: Maintenance
of the low-oxygen layer in the central Arabian Sea, Deep-Sea Res. Pt. II,
40, 673–685, 1993.
Oschlies, A., Duteil, O., Getzlaff, J., Koeve, W., Landolfi, A., and
Schmidtko, S.: Patterns of deoxygenation: sensitivity to natural and
anthropogenic drivers, Philosophical Transactions of the Royal Society A:
Mathematical, Phys. Eng. Sci., 375, 20160325, https://doi.org/10.1098/rsta.2016.0325, 2017.
Oschlies, A., Brandt, P., Stramma, L., and Schmidtko, S.: Drivers and
mechanisms of ocean deoxygenation, Nat. Geosci., 11, 467–473, 2018.
Oschlies, A. and Garcon, V.: Eddy-induced enhancement of primary production
in a model of the North Atlantic Ocean, Nature, 394, 266–269, https://doi.org/10.1038/28373 1998.
Oschlies, A., Schulz, K. G., Riebesell, U., and Schmittner, A.: Simulated
21st century's increase in oceanic suboxia by CO2-enhanced biotic
carbon export, Global Biogeochem. Cy., 22, GB4008, https://doi.org/10.1029/2007gb003147, 2008.
Oschlies, A., Koeve, W., Landolfi, A., and Kähler, P.: Loss of fixed
nitrogen causes net oxygen gain in a warmer future ocean, Nat.
Commun., 10, 2805, https://doi.org/10.1038/s41467-019-10813-w, 2019.
Palter, J. B. and Trossman, D. S.: The Sensitivity of Future Ocean Oxygen to
Changes in Ocean Circulation, Global Biogeochem. Cy., 32, 738–751,
2018.
Park, W., Keenlyside, N., Latif, M., Stroh, A., Redler, R., Roeckner, E.,
and Madec, G.: Tropical Pacific Climate and Its Response to Global Warming
in the Kiel Climate Model, J. Climate, 22, 71–92, 2009.
Pichevin, L., Bard, E., Martinez, P., and Billy, I.: Evidence of ventilation
changes in the Arabian Sea during the late Quaternary: Implication for
denitrification and nitrous oxide emission, Global Biogeochem. Cy.,
21, GB4008, https://doi.org/10.1029/2006gb002852, 2007.
Piontkovski, S. A. and Al-Oufi, H. S.: The Omani shelf hypoxia and the
warming Arabian Sea, Int. J. Environ. Stud., 72,
256–264, 2015.
Piontkovski, S. A., Queste, B. Y., Al-Hashmi, K. A., Al-Shaaibi, A.,
Bryantseva, Y. V., and Popova, E. A.: Subsurface algal blooms of the
northwestern Arabian Sea, Mar. Ecol. Prog. Ser.s, 566, 67–78, 2017.
Pozzato, L., van Oevelen, D., Moodley, L., Soetaert, K., and Middelburg, J.
J.: Carbon processing at the deep-sea floor of the Arabian Sea oxygen
minimum zone: A tracer approach, J. Sea Res., 78, 45–58, 2013.
Prakash, S., Ramesh, R., Sheshshayee, M. S., Dwivedi, R. M., and Raman, M.:
Quantification of new production during a winter Noctiluca scintillans bloom in the Arabian Sea,
Geophys. Res. Lett., 35, L08604, https://doi.org/10.1029/2008gl033819, 2008.
Prakash, S., Roy, R., and Lotliker, A.: Revisiting the Noctiluca scintillans
paradox in northern Arabian Sea, Current Sci., 113, 1429–1434, 2017.
Prasanna Kumar, S., Nuncio, M., Narvekar, J., Kumar, A., Sardesai, d. S., De
Souza, S., Gauns, M., Ramaiah, N., and Madhupratap, M.: Are eddies nature's
trigger to enhance biological productivity in the Bay of Bengal?,
Geophys. Res. Lett., 31, L07309, https://doi.org/10.1029/2003GL019274, 2004.
Pratihary, A. K., Naqvi, S. W. A., Narvenkar, G., Kurian, S., Naik, H., Naik, R., and Manjunatha, B. R.: Benthic mineralization and nutrient exchange over the inner continental shelf of western India, Biogeosciences, 11, 2771–2791, https://doi.org/10.5194/bg-11-2771-2014, 2014.
Queste, B. Y., Vic, C., Heywood, K. J., and Piontkovski, S. A.: Physical
Controls on Oxygen Distribution and Denitrification Potential in the North
West Arabian Sea, Geophys. Res. Lett., 45, 4143–4152, 2018.
Raman, A. V., Damodaran, R., Levin, L. A., Ganesh, T., Rao, Y. K. V.,
Nanduri, S., and Madhusoodhanan, R.: Macrobenthos relative to the oxygen
minimum zone on the East Indian margin, Bay of Bengal, Mar. Ecol., 36,
679–700, 2015.
Ramaswamy, V., Nair, R. R., Manganini, S., Haake, B., and Ittekkot, V.:
Lithogenic fluxes to the deep Arabian Sea measured by sediment traps, Deep-Sea Res., 38, 169–184, 1991.
Rao, C. K., Naqvi, S. W. A., Kumar, M. D., Varaprasad, S. J. D., Jayakumar,
D. A., George, M. D., and Singbal, S. Y. S.: Hydrochemistry of the Bay of
Bengal: possible reasons for a different water-column cycling of carbon and
nitrogen from the Arabian Sea, Mar. Chem., 47, 279–290, 1994.
Rao, R. R., Molinari, R. L., and Festa, J. F.: Evolution of the
Climatological Near-Surface Thermal Structure of the Tropical Indian Ocean –
1. Description of Mean Monthly Mixed Layer Depth, and Sea Surface
Temperature, Surface Current, and Surface Meteorological Fields, J.
Geophys. Res., 94, 10801–10815, 1989.
Resplandy, L.: Will ocean zones with low oxygen levels expand or shrink?,
Nature, 557, 314–315, 2018.
Resplandy, L., Lévy, M., Madec, G., Pous, S., Aumont, O., and Kumar, D.:
Contribution of mesoscale processes to nutrient budgets in the Arabian Sea,
J. Geophys. Res.-Ocean., 116, C11007, https://doi.org/10.1029/2011JC007006, 2011.
Resplandy, L., Lévy, M., Bopp, L., Echevin, V., Pous, S., Sarma, V. V. S. S., and Kumar, D.: Controlling factors of the oxygen balance in the Arabian Sea's OMZ, Biogeosciences, 9, 5095–5109, https://doi.org/10.5194/bg-9-5095-2012, 2012.
Resplandy, L., Lévy, M., and McGillicuddy Jr., D. J.: Effects of
Eddy-Driven Subduction on Ocean Biological Carbon Pump, Global
Biogeochem. Cy., 33, 1071–1084, 2019.
Rixen, T. and Ittekkot, V.: Nitrogen deficits in the Arabian Sea,
implications from a three component mixing analysis, Deep-Sea Res. Pt. II,
1879–1891, 2005.
Rixen, T., Haake, B., and Ittekkot, V.: Sedimentation in the western Arabian
Sea: the role of coastal and open-ocean upwelling, Deep-Sea Res. Pt. II, 47,
2155–2178, 2000.
Rixen, T., Goyet, C., and Ittekkot, V.: Diatoms and their influence on the biologically mediated uptake of atmospheric CO2 in the Arabian Sea upwelling system, Biogeosciences, 3, 1–13, https://doi.org/10.5194/bg-3-1-2006, 2006.
Rixen, T., Gaye, B., and Emeis, K.-C.: The monsoon, carbon fluxes, and the
organic carbon pump in the northern Indian Ocean, Prog. Oceanogr.,
175, 24–39, 2019a.
Rixen, T., Gaye, B., Emeis, K.-C., and Ramaswamy, V.: The ballast effect of lithogenic matter and its influences on the carbon fluxes in the Indian Ocean, Biogeosciences, 16, 485–503, https://doi.org/10.5194/bg-16-485-2019, 2019b.
Rixen, T., Baum, A., Gaye, B., and Nagel, B.: Seasonal and interannual variations in the nitrogen cycle in the Arabian Sea, Biogeosciences, 11, 5733–5747, https://doi.org/10.5194/bg-11-5733-2014, 2014.
Rosenberg, R.: Marine benthic faunal successional stages and related
sediment activity, Sci. Mar., 66, 107–119, 2001.
Saltzman, J. and Wishner, K. F.: Zooplankton ecology in the eastern tropical
Pacific oxygen minimum zone above a seamount: 2. Vertical distribution of
copepods, Deep-Sea Res. Pt. I, 44,
931–954, 1997.
Sánchez-Baracaldo, P.: Origin of marine planktonic cyanobacteria,
Sci. Rep., 5, 17418, https://doi.org/10.1038/srep17418, 2015.
Saraswathy, M. and Iyer, H. K.: Ecology of Pleuromamma indica Wolfenden (Copepoda – Calanoida)
in the Indian Ocean, Indian J. Mar. Sci., 15, 219–222, 1986.
Sarkar, A., Sengupta, S., McArthur, J. M., Bera, M. K., Bushan, R., Samanta,
A., and Agrawal, S.: Evolution of Ganges-Brahmaputra western delta plain:
clues from sedimentology and carbon isotopes, Quaternary Sci. Rev.,
28, 2564–2581, 2009.
Sarma, V. and Udaya Bhaskar, T.: Ventilation of oxygen to oxygen minimum
zone due to anticyclonic eddies in the Bay of Bengal, J. Geophys.
Res.-Biogeo., 123, 2145–2153, 2018.
Sarma, V., Jagadeesan, L., Dalabehera, H., Rao, D., Kumar, G., Durgadevi,
D., Yadav, K., Behera, S., and Priya, M.: Role of eddies on intensity of
oxygen minimum zone in the Bay of Bengal, Cont. Shelf Res., 168,
48–53, 2018.
Sastry, J. S. and D'Souza, R. S.: Upwelling & Upward Mixing in the
Arabian Sea, Indian J. Mar. Sci., 1, 17–27, 1972.
Schlitzer, R.: Applying the adjoint method for biogeochemical modeling,
Export of particulate organic matter in the World Ocean, in: Inverse Methods
in Biogeochemical Cycles, edited by: Kasibhata, P., AGU Monograph, AGU, 2000.
Schlitzer, R.: Carbon export fluxes in the Southern Ocean: results from
inverse modeling and comparison with satellite-based estimates, Deep-Sea
Res. Pt. II, 49, 1623–1644, 2002.
Schmidt, H., Czeschel, R., and Visbeck, M.: Seasonal variability of the circulation in the Arabian Sea at intermediate depth and its link to the Oxygen Minimum Zone, Ocean Sci. Discuss., https://doi.org/10.5194/os-2020-9, in review, 2020.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic
oxygen content during the past five decades, Nature, 542, 335–339, https://doi.org/10.1038/nature21399, 2017.
Schott, F. and McCreary Jr., J. P.: The monsoon circulation of the Indian
Ocean, Prog. Oceanogr., 51, 1–123, 2001.
Schott, G.: Geographie des Indischen und Stillen Ozeans, Boysen, Hamburg,
Germany, 1935.
Schunck, H., Lavik, G., Desai, D. K., Großkopf, T., Kalvelage, T.,
Löscher, C. R., Paulmier, A., Contreras, S., Siegel, H., Holtappels, M.,
Rosenstiel, P., Schilhabel, M. B., Graco, M., Schmitz, R. A., Kuypers, M. M.
M., and LaRoche, J.: Giant Hydrogen Sulfide Plume in the Oxygen Minimum Zone
off Peru Supports Chemolithoautotrophy, PLOS ONE, 8, e68661, https://doi.org/10.1371/journal.pone.0068661, 2013.
Schütte, F., Karstensen, J., Krahmann, G., Hauss, H., Fiedler, B., Brandt, P., Visbeck, M., and Körtzinger, A.: Characterization of “dead-zone” eddies in the eastern tropical North Atlantic, Biogeosciences, 13, 5865–5881, https://doi.org/10.5194/bg-13-5865-2016, 2016.
Schwartz, M. C., Woulds, C., and Cowie, G. L.: Sedimentary denitrification
rates across the Arabian Sea oxygen minimum zone, Deep-Sea Res. Pt. II, 56, 324–332, 2009.
Séférian, R., Berthet, S., Yool, A., Palmiéri, J., Bopp, L.,
Tagliabue, A., Kwiatkowski, L., Aumont, O., Christian, J., Dunne, J.,
Gehlen, M., Ilyina, T., John, J. G., Li, H., Long, M. C., Luo, J. Y.,
Nakano, H., Romanou, A., Schwinger, J., Stock, C., Santana-Falcón, Y.,
Takano, Y., Tjiputra, J., Tsujino, H., Watanabe, M., Wu, T., Wu, F., and
Yamamoto, A.: Tracking Improvement in Simulated Marine Biogeochemistry
Between CMIP5 and CMIP6, Curr. Clim. Change Rep., 6, 95–119, 2020.
Segschneider, J. and Bendtsen, J.: Temperature-dependent remineralization in
a warming ocean increases surface pCO2 through changes in marine ecosystem
composition, Global Biogeochem. Cy., 27, 1214–1225, 2013.
Segschneider, J., Schneider, B., and Khon, V.: Climate and marine biogeochemistry during the Holocene from transient model simulations, Biogeosciences, 15, 3243–3266, https://doi.org/10.5194/bg-15-3243-2018, 2018.
Seiwell, H. R.: The minimum oxygen concentration in the western basin of the
North Atlantic, Papers Phys. Oceanogr. Meteorol., 5, 3–18,
1937.
Sen Gupta, R. and Naqvi, S. W. A.: Chemical Oceanography of the Indian
Ocean, North of the Equator, Deep-Sea Res., 31, 671–706, 1984.
Sewell, R. B. S. and Fage, L.: Minimum Oxygen Layer in the Ocean, Nature,
162, 949–951, 1948.
Shenoy, D. M., Suresh, I., Uskaikar, H., Kurian, S., Vidya, P. J.,
Shirodkar, G., Gauns, M. U., and Naqvi, S. W. A.: Variability of dissolved
oxygen in the Arabian Sea Oxygen Minimum Zone and its driving mechanisms,
J. Mar. Syst., 204, 103310, https://doi.org/10.1016/j.jmarsys.2020.103310, 2020.
Shetye, S. R. and Shenoi, S. S. C.: Seasonal cycle of surface circulation in
the coastal North Indian Ocean, P. Indian A.
S.-Earth, 97, 53–62, 1988.
Shetye, S. R., Gouveia, A. D., Shenoi, S. S. C., Sundar, D., Michael, G. S.,
Almeida, A. M., and Santanam, K.: Hydrography and circulation off the west
coast of India during the Southwest Monsoon 1987, J. Mar.
Res., 48, 359–378, 1990.
Sigman, D. M., Granger, J., DiFiore, P. J., Lehmann, M. F., Ho, R., Cane,
G., and van Geen, A.: Coupled nitrogen and oxygen isotope measurements of
nitrate along the eastern North Pacific margin, Global Biogeochem.
Cy., 19, GB4022, https://doi.org/10.1029/2005GB002458, 2005.
Singh, A., Gandhi, N., Ramesh, R., and Prakash, S.: Role of cyclonic eddy in
enhancing primary and new production in the Bay of Bengal, J. Sea
Res., 97, 5–13, 2015.
Smallwood, B. J., Wolff, G. A., Bett, B. J., Smith, C. R., Hoover, D., Gage,
J. D., and Patience, A.: Megafauna Can Control the Quality of Organic Matter
in Marine Sediments, Naturwissenschaften, 86, 320–324, 1999.
Smith, C. R., A. Levin, L., Hoover, D. J., McMurtry, G., and Gage, J. D.:
Variations in bioturbation across the oxygen minimum zone in the northwest
Arabian Sea, Deep-Sea Res. Pt. II, 47,
227–257, 2000.
Smith, S. L.: Understanding the Arabian Sea: Reflections on the 1994–1996
Arabian Sea Expedition, Deep-Sea Res. Pt. II, 48, 1385–1402, 2001.
Smith, S. L. and Madhupratap, M.: Mesozooplankton of the Arabian Sea:
Patterns influenced by seasons, upwelling, and oxygen concentrations,
Prog. Oceanogr., 65, 214–239, 2005.
Smith, S. L., Roman, M., Prusova, I., Wishner, K., Gowing, M., Codispoti, L.
A., Barber, R., Marra, J., and Flagg, C.: Seasonal response of zooplankton
to monsoonal reversals in the Arabian Sea, Deep-Sea Res. Pt. II, 45, 2369–2403, 1998a.
Smith, S. L., Codispoti, L. A., Morrison, J. M., and Barber, R. T.: The
1994–1996 Arabian Sea Expedition: An integrated, interdisciplinary
investigation of the response of the northwestern Indian Ocean to monsoonal
forcing, Deep-Sea Res. Pt. II, 45,
1905–1915, 1998b.
Smith, T. M., Reynolds, R. W., Peterson, T. C., and Lawrimore, J.:
Improvements to NOAA's historival merged land-ocean surface temperature
analysis (1880–2006), J. Climate, 21, 2283–2296, 2008.
Sokoll, S., Holtappels, M., Lam, P., Collins, G., Schlüter, M., Lavik,
G., and Kuypers, M.: Benthic Nitrogen Loss in the Arabian Sea Off Pakistan,
Front. Microbiol., 3, 1–17, 2012.
Somasundar, K., Rajendran, A., Dileep Kumar, M., and Sen Gupta, R.: Carbon
and nitrogen budgets of the Arabian Sea, Mar. Chem., 30, 363–377,
1990.
Somes, C. J., Oschlies, A., and Schmittner, A.: Isotopic constraints on the pre-industrial oceanic nitrogen budget, Biogeosciences, 10, 5889–5910, https://doi.org/10.5194/bg-10-5889-2013, 2013.
Stramma, L., Fischer, J., and Schott, F.: The flow field off southwest India
at 8∘ N during the southwest monsoon of August 1993, J. Mar.
Res., 54, 55-72, 1996.
Stramma, L., Johnson, G. C., Sprintall, J., and Mohrholz, V.: Expanding
oxygen-minimum zones in the tropical oceans, Science, 320, 655–658, 2008.
Stramma, L., Johnson, G. C., Firing, E., and Schmidtko, S.: Eastern Pacific
oxygen minimum zones: Supply paths and multidecadal changes, J. Geophys.
Res., 115, C09011, https://doi.org/10.1029/2009jc005976, 2010a.
Stramma, L., Schmidtko, S., Levin, L. A., and Johnson, G. C.: Ocean oxygen
minima expansions and their biological impacts, Deep-Sea Res. Pt. I, 57, 587–595, 2010b.
Sudheesh, V., Gupta, G. V. M., Sudharma, K. V., Naik, H., Shenoy, D. M.,
Sudhakar, M., and Naqvi, S. W. A.: Upwelling intensity modulates N2O
concentrations over the western Indian shelf, J. Geophys.
Res.-Ocean., 121, 8551–8565, 2016.
Suess, E.: Particulate organic carbon flux in the oceans – surface
productivity and oxygen utilization, Nature, 288, 260–263, 1980.
Suthhof, A., Ittekkot, V., and Gaye-Haake, B.: Millenial-scale oscillation
of denitrification intensitiy in the Arabian Sea during the late Quaternary
and its potential influence on atmospheric N2O and global climate,
Global Biogeochem. Cy., 15, 637–650, 2001.
Sverdrup, H. U.: On the Explanation of the Oxygen Minima and Maxima in the
Oceans1), ICES J. Mar. Sci., 13, 163–172, 1938.
Sverdrup, H. U., Johnson, M. W., and Flemming, R. H.: The Oceans, their
physics chemistry and general biology, Prentice-Hall, Englewood Cliffs,
N.J., 1942.
Swallow, J. C.: Some aspects of the physical oceanography of the Indian
Ocean, Deep-Sea Res. Pt. A, 31, 639–650,
1984.
Sweetman, A. K., Chelsky, A., Pitt, K. A., Andrade, H., van Oevelen, D., and
Renaud, P. E.: Jellyfish decomposition at the seafloor rapidly alters
biogeochemical cycling and carbon flow through benthic food-webs, Limnol. Oceanogr., 61, 1449–1461, 2016.
Taylor, K. E., Stouffer, R. J., and Meehl, G. A.: An Overview of CMIP5 and the Experiment Design, Bull. Am. Meteorol. Soc., 93, 485–498 https://doi.org/10.1175/BAMS-D-11-00094.1, 2012.
Tesdal, J.-E., Galbraith, E. D., and Kienast, M.: Nitrogen isotopes in bulk marine sediment: linking seafloor observations with subseafloor records, Biogeosciences, 10, 101–118, https://doi.org/10.5194/bg-10-101-2013, 2013.
Thamdrup, B., Dalsgaard, T., and Revsbech, N. P.: Widespread functional
anoxia in the oxygen minimum zone of the Eastern South Pacific, Deep-Sea
Res. Pt. I, 65, 36–45, 2012.
Ulloa, O., Canfield, D. E., DeLong, E. F., Letelier, R. M., and Stewart, F.
J.: Microbial oceanography of anoxic oxygen minimum zones, P.
Natl. Acad. Sci., 109, 15996, https://doi.org/10.1073/pnas.1205009109, 2012.
Unger, D., Schaefer, P., Ittekkot, V., and Gaye, B.: Nitrogen isotopic
composition of sinking particles from the southern Bay of Bengal: Evidence
for variable nitrogen sources, Deep-Sea Res., 1, 53, 1658–1676, 2006.
Van Mooy, B. A. S., Keil, R. G., and Devol, A. H.: Impact of suboxia on
sinking particulate organic carbon: Enhanced carbon flux and preferential
degradation of amino acids via denitrification, Geochim. Cosmochim.
Ac., 66, 457–465, 2002.
Vaquer-Sunyer, R. and Duarte, C. M.: Thresholds of hypoxia for marine
biodiversity, P. Natl. Acad. Sci., 105, 15452, https://doi.org/10.1073/pnas.0803833105,
2008.
Vic, C., Roullet, G., Capet, X., Carton, X., Molemaker, M. J., and Gula, J.:
Eddy topography interactions and the fate of the Persian Gulf Outflow,
J. Geophys. Res.-Ocean., 120, 6700–6717, 2015.
Vinogradov, M. E. and Voronina, N. M.: Influence of the oxygen deficit on
the distribution of plankton in the Arabian Sea, Deep-Sea Res.
Oceanogr. Abstracts, 9, 523–530, 1962.
Voss, M., Deutsch, B., Elmgren, R., Humborg, C., Kuuppo, P., Pastuszak, M., Rolff, C., and Schulte, U.: Source identification of nitrate by means of isotopic tracers in the Baltic Sea catchments, Biogeosciences, 3, 663–676, https://doi.org/10.5194/bg-3-663-2006, 2006.
Wang, L., Lin, X., Goes, J. I., and Lin, S.: Phylogenetic Analyses of Three
Genes of Pedinomonas noctilucae, the Green Endosymbiont of the Marine
Dinoflagellate Noctiluca scintillans, Reveal its Affiliation to the Order
Marsupiomonadales (Chlorophyta, Pedinophyceae) under the Reinstated Name
Protoeuglena noctilucae, Protist, 167, 205–216, 2016.
Ward, B. B., Devol, A. H., Rich, J. J., Chang, B. X., Bulow, S. E., Naik,
H., Pratihary, A., and Jayakumar, A.: Denitrification as the dominant
nitrogen loss process in the Arabian Sea, Nature, 461, 78–81, 2009.
Weeks, S. J., Currie, B., and Bakun, A.: Massive emissions of toxic gas in
the Atlantic, Nature, 415, 493–494, 2002.
White, C. M., Woulds, C., Cowie, G. L., Stott, A., and Kitazato, H.:
Resilience of benthic ecosystem C-cycling to future changes in dissolved
oxygen availability, Deep-Sea Res. Pt. II, 161, 29–37, 2019.
Wishner, K. F., Ashjian, C. J., Gelfman, C., Gowing, M. M., Kann, L., Levin,
L. A., Mullineaux, L. S., and Saltzman, J.: Pelagic and benthic ecology of
the lower interface of the Eastern Tropical Pacific oxygen minimum zone,
Deep-Sea Res. Pt. I, 42, 93–115, 1995.
Wishner, K. F., Gowing, M. M., and Gelfman, C.: Mesozooplankton biomass in
the upper 1000 m in the Arabian Sea: overall seasonal and geographic
patterns, and relationship to oxygen gradients, Deep-Sea Res. Pt. II, 45, 2405–2432, 1998.
Wishner, K. F., Gelfman, C., Gowing, M. M., Outram, D. M., Rapien, M., and
Williams, R. L.: Vertical zonation and distributions of calanoid copepods
through the lower oxycline of the Arabian Sea oxygen minimum zone, Prog. Oceanogr., 78, 163–191, 2008.
Woulds, C., Cowie, G. L., Levin, L. A., Andersson, J. H., Middelburg, J. J.,
Vandewiele, S., Lamont, P. A., Larkin, K. E., Gooday, A. J., Schumacher, S.,
Whitcraft, C., Jeffreys, R. M., and Schwartz, M.: Oxygen as a control on sea
floor biological communities and their roles in sedimentary carbon cycling,
Limnol. Oceanogr., 52, 1698–1709, 2007.
Woulds, C., Andersson, J. H., Cowie, G. L., Middelburg, J. J., and Levin, L.
A.: The short-term fate of organic carbon in marine sediments: Comparing the
Pakistan margin to other regions, Deep-Sea Res. Pt. II, 56, 393–402, 2009.
Wyrtki, K.: Physical Oceanography of the Indian Ocean, in: The Biology of
the Indian Ocean, edited by: Zeitschel, B., Springer Verlag, Berlin, Heidelberg,
New York, 1973.
You, Y.: Seasonal variations of thermocline circulation and ventilation in
the Indian Ocean, J. Geophys. Res., 102, 10391–10422,
1997.
Short summary
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to human-induced global changes. This includes the occurrence of anoxic events on the Indian shelf and affects benthic ecosystems and the pelagic ecosystem structure in the Arabian Sea. Consequences for biogeochemical cycles are unknown, which, in addition to the poor representation of mesoscale features, reduces the reliability of predictions of the future OMZ development in the northern Indian Ocean.
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to...
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