Articles | Volume 22, issue 9
https://doi.org/10.5194/bg-22-2239-2025
© Author(s) 2025. 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-22-2239-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
13 May 2025
Research article |
| 13 May 2025
| 13 May 2025
Sea ice and mixed layer depth influence on nitrate depletion and associated isotopic effects in the Drake Passage–Weddell Sea region, Southern Ocean
Aymeric P. M. Servettaz
CORRESPONDING AUTHOR
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Institute of Arctic Climate and Environment Research, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Yuta Isaji
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Chisato Yoshikawa
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Yanghee Jang
Marine Radioactive Monitoring Group, Marine Environment Research Institute, Korea Marine Environment Management Corporation, Busan 49111, Republic of Korea
Boo-Keun Khim
CORRESPONDING AUTHOR
Department of Oceanography and Marine Research Institute, Pusan National University, Busan 46241, Republic of Korea
Yeongjun Ryu
Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
Daniel M. Sigman
Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
Nanako O. Ogawa
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Francisco J. Jiménez-Espejo
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
Instituto Andaluz de Ciencias de la Tierra, Spanish Research Council, 18100 Armilla, Granada, Spain
Naohiko Ohkouchi
Biogeochemistry Research Center, Japan Agency for Marine–Earth Science and Technology, Yokosuka, 237-0061 Kanagawa, Japan
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The Cryosphere, 17, 5373–5389, https://doi.org/10.5194/tc-17-5373-2023, https://doi.org/10.5194/tc-17-5373-2023, 2023
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It has been previously observed in polar regions that the atmospheric temperature is warmer during precipitation events. Here, we use a regional atmospheric model to quantify the temperature changes associated with snowfall events across Antarctica. We show that more intense snowfall is statistically associated with a warmer temperature anomaly compared to the seasonal average, with the largest anomalies seen in winter. This bias may affect water isotopes in ice cores deposited during snowfall.
Aymeric P. M. Servettaz, Anaïs J. Orsi, Mark A. J. Curran, Andrew D. Moy, Amaelle Landais, Joseph R. McConnell, Trevor J. Popp, Emmanuel Le Meur, Xavier Faïn, and Jérôme Chappellaz
Clim. Past, 19, 1125–1152, https://doi.org/10.5194/cp-19-1125-2023, https://doi.org/10.5194/cp-19-1125-2023, 2023
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We overcame the limitations of satellite and reanalysis sea surface salinity (SSS) datasets and produced a gap-free gridded SSS product with reasonable accuracy and a spatial resolution of 1 km using a machine learning model. Our data enabled the recognition of SSS distribution and movement patterns of the Changjiang diluted water (CDW) front in the East China Sea (ECS) during summer. These results will further advance our understanding and monitoring of long-term SSS variations in the ECS.
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It has been previously observed in polar regions that the atmospheric temperature is warmer during precipitation events. Here, we use a regional atmospheric model to quantify the temperature changes associated with snowfall events across Antarctica. We show that more intense snowfall is statistically associated with a warmer temperature anomaly compared to the seasonal average, with the largest anomalies seen in winter. This bias may affect water isotopes in ice cores deposited during snowfall.
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Molly O. Patterson, Richard H. Levy, Denise K. Kulhanek, Tina van de Flierdt, Huw Horgan, Gavin B. Dunbar, Timothy R. Naish, Jeanine Ash, Alex Pyne, Darcy Mandeno, Paul Winberry, David M. Harwood, Fabio Florindo, Francisco J. Jimenez-Espejo, Andreas Läufer, Kyu-Cheul Yoo, Osamu Seki, Paolo Stocchi, Johann P. Klages, Jae Il Lee, Florence Colleoni, Yusuke Suganuma, Edward Gasson, Christian Ohneiser, José-Abel Flores, David Try, Rachel Kirkman, Daleen Koch, and the SWAIS 2C Science Team
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Preprint withdrawn
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N. F. Ishikawa, M. Yamane, H. Suga, N. O. Ogawa, Y. Yokoyama, and N. Ohkouchi
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Weitian Ding, Urumu Tsunogai, and Fumiko Nakagawa
Biogeosciences, 21, 4717–4722, https://doi.org/10.5194/bg-21-4717-2024, https://doi.org/10.5194/bg-21-4717-2024, 2024
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Past studies have used the Δ17O of stream nitrate to estimate the gross nitrification rates (GNRs) in each forested catchment by approximating the Δ17O value of soil nitrate to be equal to that of stream nitrate. Based on inference and calculation of measured data, we found that this approximation resulted in an overestimated GNR. Therefore, it is essential to clarify and verify the Δ17O NO3− values in forested soils and streams before applying the Δ17O values of stream NO3− to GNR estimation.
Elise D. Rivett, Wenjuan Ma, Nathaniel E. Ostrom, and Eric L. Hegg
Biogeosciences, 21, 4549–4567, https://doi.org/10.5194/bg-21-4549-2024, https://doi.org/10.5194/bg-21-4549-2024, 2024
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Many different processes produce nitrous oxide (N2O), a potent greenhouse gas. Measuring the ratio of heavy and light nitrogen isotopes (15N/14N) for the non-exchangeable central and outer N atoms of N2O helps to distinguish sources of N2O. To accurately calculate the position-specific isotopic preference, we developed an expansion of the widely used Rayleigh model. Application of our new model to simulated and experimental data demonstrates its improved accuracy for analyzing N2O synthesis.
Eliza Harris, Philipp Fischer, Maciej P. Lewicki, Dominika Lewicka-Szczebak, Stephen J. Harris, and Fernando Perez-Cruz
Biogeosciences, 21, 3641–3663, https://doi.org/10.5194/bg-21-3641-2024, https://doi.org/10.5194/bg-21-3641-2024, 2024
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Greenhouse gases are produced and consumed via a number of pathways. Quantifying these pathways helps reduce the climate and environmental footprint of anthropogenic activities. The contribution of the pathways can be estimated from the isotopic composition, which acts as a fingerprint for these pathways. We have developed the Time-resolved FRactionation And Mixing Evaluation (TimeFRAME) model to simplify interpretation and estimate the contribution of different pathways and their uncertainty.
Kim A. P. Faassen, Jordi Vilà-Guerau de Arellano, Raquel González-Armas, Bert G. Heusinkveld, Ivan Mammarella, Wouter Peters, and Ingrid T. Luijkx
Biogeosciences, 21, 3015–3039, https://doi.org/10.5194/bg-21-3015-2024, https://doi.org/10.5194/bg-21-3015-2024, 2024
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The ratio between atmospheric O2 and CO2 can be used to characterize the carbon balance at the surface. By combining a model and observations from the Hyytiälä forest (Finland), we show that using atmospheric O2 and CO2 measurements from a single height provides a weak constraint on the surface CO2 exchange because large-scale processes such as entrainment confound this signal. We therefore recommend always using multiple heights of O2 and CO2 measurements to study surface CO2 exchange.
Nestor Gaviria-Lugo, Charlotte Läuchli, Hella Wittmann, Anne Bernhardt, Patrick Frings, Mahyar Mohtadi, Oliver Rach, and Dirk Sachse
Biogeosciences, 20, 4433–4453, https://doi.org/10.5194/bg-20-4433-2023, https://doi.org/10.5194/bg-20-4433-2023, 2023
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We analyzed how leaf wax hydrogen isotopes in continental and marine sediments respond to climate along one of the strongest aridity gradients in the world, from hyperarid to humid, along Chile. We found that under extreme aridity, the relationship between hydrogen isotopes in waxes and climate is non-linear, suggesting that we should be careful when reconstructing past hydrological changes using leaf wax hydrogen isotopes so as to avoid overestimating how much the climate has changed.
Ralf Conrad and Peter Claus
Biogeosciences, 20, 3625–3635, https://doi.org/10.5194/bg-20-3625-2023, https://doi.org/10.5194/bg-20-3625-2023, 2023
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Knowledge of carbon isotope fractionation is important for the assessment of the pathways involved in the degradation of organic matter. Propionate is an important intermediate. In the presence of sulfate, it was degraded by Syntrophobacter species via acetate to CO2. In the absence of sulfate, it was mainly consumed by Smithella and methanogenic archaeal species via butyrate and acetate to CH4. However, stable carbon isotope fractionation during the degradation process was quite small.
Alessandro Zanchetta, Linda M. J. Kooijmans, Steven van Heuven, Andrea Scifo, Hubertus A. Scheeren, Ivan Mammarella, Ute Karstens, Jin Ma, Maarten Krol, and Huilin Chen
Biogeosciences, 20, 3539–3553, https://doi.org/10.5194/bg-20-3539-2023, https://doi.org/10.5194/bg-20-3539-2023, 2023
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Carbonyl sulfide (COS) has been suggested as a tool to estimate carbon dioxide (CO2) uptake by plants during photosynthesis. However, understanding its sources and sinks is critical to preventing biases in this estimate. Combining observations and models, this study proves that regional sources occasionally influence the measurements at the 60 m tall Lutjewad tower (1 m a.s.l.; 53°24′ N, 6°21′ E) in the Netherlands. Moreover, it estimates nighttime COS fluxes to be −3.0 ± 2.6 pmol m−2 s−1.
Joel T. Bostic, David M. Nelson, and Keith N. Eshleman
Biogeosciences, 20, 2485–2498, https://doi.org/10.5194/bg-20-2485-2023, https://doi.org/10.5194/bg-20-2485-2023, 2023
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Land-use changes can affect water quality. We used tracers of pollution sources and water flow paths to show that an urban watershed exports variable sources during storm events relative to a less developed watershed. Our results imply that changing precipitation patterns combined with increasing urbanization may alter sources of pollution in the future.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2405–2424, https://doi.org/10.5194/bg-20-2405-2023, https://doi.org/10.5194/bg-20-2405-2023, 2023
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Dissolved organic carbon (DOC) is a reservoir of prime importance in the C cycle of both continental and marine systems. It has also been suggested to influence the past Earth climate but is still poorly characterized in ancient-Earth-like environments. In this paper we show how DOC analyses from modern redox-stratified lakes can evidence specific metabolic reactions and environmental factors and how these can help us to interpret the C cycle of specific periods in the Earth's past.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2347–2367, https://doi.org/10.5194/bg-20-2347-2023, https://doi.org/10.5194/bg-20-2347-2023, 2023
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We describe the C cycle of four modern stratified water bodies from Mexico, a necessary step to better understand the C cycle of primitive-Earth-like environments, which were dominated by these kinds of conditions. We highlight the importance of local external factors on the C cycle of these systems. Notably, they influence the sensitivity of the carbonate record to environmental changes. We also show the strong C-cycle variability among these lakes and their organic C sediment record.
Yifan Ma, Kuanbo Zhou, Weifang Chen, Junhui Chen, Jin-Yu Terence Yang, and Minhan Dai
Biogeosciences, 20, 2013–2030, https://doi.org/10.5194/bg-20-2013-2023, https://doi.org/10.5194/bg-20-2013-2023, 2023
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We distinguished particulate organic carbon (POC) export fluxes out of the nutrient-depleted layer (NDL) and the euphotic zone. The amount of POC export flux at the NDL base suggests that the NDL could be a hotspot of particle export. The substantial POC export flux at the NDL base challenges traditional concepts that the NDL was limited in terms of POC export. The dominant nutrient source for POC export fluxes should be subsurface nutrients, which was determined by 15N isotopic mass balance.
Clémence Paul, Clément Piel, Joana Sauze, Nicolas Pasquier, Frédéric Prié, Sébastien Devidal, Roxanne Jacob, Arnaud Dapoigny, Olivier Jossoud, Alexandru Milcu, and Amaëlle Landais
Biogeosciences, 20, 1047–1062, https://doi.org/10.5194/bg-20-1047-2023, https://doi.org/10.5194/bg-20-1047-2023, 2023
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To improve the interpretation of the δ18Oatm and Δ17O of O2 in air bubbles in ice cores, we need to better quantify the oxygen fractionation coefficients associated with biological processes. We performed a simplified analogue of the terrestrial biosphere in a closed chamber. We found a respiration fractionation in agreement with the previous estimates at the microorganism scale, and a terrestrial photosynthetic fractionation was found. This has an impact on the estimation of the Dole effect.
Adam Francis, Raja S. Ganeshram, Robyn E. Tuerena, Robert G. M. Spencer, Robert M. Holmes, Jennifer A. Rogers, and Claire Mahaffey
Biogeosciences, 20, 365–382, https://doi.org/10.5194/bg-20-365-2023, https://doi.org/10.5194/bg-20-365-2023, 2023
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Climate change is causing extensive permafrost degradation and nutrient releases into rivers with great ecological impacts on the Arctic Ocean. We focused on nitrogen (N) release from this degradation and associated cycling using N isotopes, an understudied area. Many N species are released at degradation sites with exchanges between species. N inputs from permafrost degradation and seasonal river N trends were identified using isotopes, helping to predict climate change impacts.
Mohamed Ayache, Jean-Claude Dutay, Kazuyo Tachikawa, Thomas Arsouze, and Catherine Jeandel
Biogeosciences, 20, 205–227, https://doi.org/10.5194/bg-20-205-2023, https://doi.org/10.5194/bg-20-205-2023, 2023
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The neodymium (Nd) is one of the most useful tracers to fingerprint water mass provenance. However, the use of Nd is hampered by the lack of adequate quantification of the external sources. Here, we present the first simulation of dissolved Nd concentration and Nd isotopic composition in the Mediterranean Sea using a high-resolution model. We aim to better understand how the various external sources affect the Nd cycle and particularly assess how it is impacted by atmospheric inputs.
Marta Santos-Garcia, Raja S. Ganeshram, Robyn E. Tuerena, Margot C. F. Debyser, Katrine Husum, Philipp Assmy, and Haakon Hop
Biogeosciences, 19, 5973–6002, https://doi.org/10.5194/bg-19-5973-2022, https://doi.org/10.5194/bg-19-5973-2022, 2022
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Terrestrial sources of nitrate are important contributors to the nutrient pool in the fjords of Kongsfjorden and Rijpfjorden in Svalbard during the summer, and they sustain most of the fjord primary productivity. Ongoing tidewater glacier retreat is postulated to favour light limitation and less dynamic circulation in fjords. This is suggested to encourage the export of nutrients to the middle and outer part of the fjord system, which may enhance primary production within and in offshore areas.
Marlene Dordoni, Michael Seewald, Karsten Rinke, Kurt Friese, Robert van Geldern, Jakob Schmidmeier, and Johannes A. C. Barth
Biogeosciences, 19, 5343–5355, https://doi.org/10.5194/bg-19-5343-2022, https://doi.org/10.5194/bg-19-5343-2022, 2022
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Organic matter (OM) turnover into dissolved inorganic carbon (DIC) was investigated by means of carbon isotope mass balances in Germany's largest water reservoir. This includes a metalimnetic oxygen minimum (MOM). Autochthonous particulate organic carbon (POC) was the main contributor to DIC, with rates that were highest for the MOM. Generally low turnover rates outline the environmental fragility of this water body in the case that OM loads increase due to storm events or land use changes.
Frédérique M. S. A. Kirkels, Hugo J. de Boer, Paulina Concha Hernández, Chris R. T. Martes, Marcel T. J. van der Meer, Sayak Basu, Muhammed O. Usman, and Francien Peterse
Biogeosciences, 19, 4107–4127, https://doi.org/10.5194/bg-19-4107-2022, https://doi.org/10.5194/bg-19-4107-2022, 2022
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The distinct carbon isotopic values of C3 and C4 plants are widely used to reconstruct past hydroclimate, where more C3 plants reflect wetter and C4 plants drier conditions. Here we examine the impact of regional hydroclimatic conditions on plant isotopic values in the Godavari River basin, India. We find that it is crucial to identify regional plant isotopic values and consider drought stress, which introduces a bias in C3 / C4 plant estimates and associated hydroclimate reconstructions.
Mhlangabezi Mdutyana, Tanya Marshall, Xin Sun, Jessica M. Burger, Sandy J. Thomalla, Bess B. Ward, and Sarah E. Fawcett
Biogeosciences, 19, 3425–3444, https://doi.org/10.5194/bg-19-3425-2022, https://doi.org/10.5194/bg-19-3425-2022, 2022
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Nitrite-oxidizing bacteria in the winter Southern Ocean show a high affinity for nitrite but require a minimum (i.e., "threshold") concentration before they increase their rates of nitrite oxidation significantly. The classic Michaelis–Menten model thus cannot be used to derive the kinetic parameters, so a modified equation was employed that also yields the threshold nitrite concentration. Dissolved iron availability may play an important role in limiting nitrite oxidation.
Weitian Ding, Urumu Tsunogai, Fumiko Nakagawa, Takashi Sambuichi, Hiroyuki Sase, Masayuki Morohashi, and Hiroki Yotsuyanagi
Biogeosciences, 19, 3247–3261, https://doi.org/10.5194/bg-19-3247-2022, https://doi.org/10.5194/bg-19-3247-2022, 2022
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Excessive leaching of nitrate from forested catchments during storm events degrades water quality and causes eutrophication in downstream areas. Thus, tracing the source of nitrate increase during storm events in forested streams is important for sustainable forest management. Based on the isotopic compositions of stream nitrate, including Δ17O, this study clarifies that the source of stream nitrate increase during storm events was soil nitrate in the riparian zone.
Nicolas Séon, Romain Amiot, Guillaume Suan, Christophe Lécuyer, François Fourel, Fabien Demaret, Arnauld Vinçon-Laugier, Sylvain Charbonnier, and Peggy Vincent
Biogeosciences, 19, 2671–2681, https://doi.org/10.5194/bg-19-2671-2022, https://doi.org/10.5194/bg-19-2671-2022, 2022
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We analysed the oxygen isotope composition of bones and teeth of four marine species possessing regional heterothermies. We observed a consistent link between oxygen isotope composition and temperature heterogeneities recorded by classical methods. This opens up new perspectives on the determination of the thermoregulatory strategies of extant marine vertebrates where conventional methods are difficult to apply, but also allows us to investigate thermophysiologies of extinct vertebrates.
Yuwei Liu, Guofeng Zhu, Zhuanxia Zhang, Zhigang Sun, Leilei Yong, Liyuan Sang, Lei Wang, and Kailiang Zhao
Biogeosciences, 19, 877–889, https://doi.org/10.5194/bg-19-877-2022, https://doi.org/10.5194/bg-19-877-2022, 2022
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We took the water cycle process of soil–plant–atmospheric precipitation as the research objective. In the water cycle of soil–plant–atmospheric precipitation, precipitation plays the main controlling role. The main source of replenishment for alpine meadow plants is precipitation and alpine meltwater; the main source of replenishment for forest plants is soil water; and the plants in the arid foothills mainly use groundwater.
Roberto Velázquez-Ochoa, María Julia Ochoa-Izaguirre, and Martín Federico Soto-Jiménez
Biogeosciences, 19, 1–27, https://doi.org/10.5194/bg-19-1-2022, https://doi.org/10.5194/bg-19-1-2022, 2022
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Our research is the first approximation to understand the δ13C macroalgal variability in one of the most diverse marine ecosystems in the world, the Gulf of California. The life-form is the principal cause of δ13C macroalgal variability, mainly taxonomy. However, changes in habitat characteristics and environmental conditions also influence the δ13C macroalgal variability. The δ13C macroalgae is indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation.
Raquel F. Flynn, Thomas G. Bornman, Jessica M. Burger, Shantelle Smith, Kurt A. M. Spence, and Sarah E. Fawcett
Biogeosciences, 18, 6031–6059, https://doi.org/10.5194/bg-18-6031-2021, https://doi.org/10.5194/bg-18-6031-2021, 2021
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Biological activity in the shallow Weddell Sea affects the biogeochemistry of recently formed deep waters. To investigate the drivers of carbon and nutrient export, we measured rates of primary production and nitrogen uptake, characterized the phytoplankton community, and estimated nutrient depletion ratios across the under-sampled western Weddell Sea in mid-summer. Carbon export was highest at the ice shelves and was determined by a combination of physical, chemical, and biological factors.
Stéphanie H. M. Jacquet, Christian Tamburini, Marc Garel, Aurélie Dufour, France Van Vambeke, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 5891–5902, https://doi.org/10.5194/bg-18-5891-2021, https://doi.org/10.5194/bg-18-5891-2021, 2021
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We compared carbon remineralization rates (MRs) in the western and central Mediterranean Sea in late spring during the PEACETIME cruise, as assessed using the barium tracer. We reported higher and deeper (up to 1000 m depth) MRs in the western basin, potentially sustained by an additional particle export event driven by deep convection. The central basin is the site of a mosaic of blooming and non-blooming water masses and showed lower MRs that were restricted to the upper mesopelagic layer.
Shinsuke Kawagucci, Yohei Matsui, Akiko Makabe, Tatsuhiro Fukuba, Yuji Onishi, Takuro Nunoura, and Taichi Yokokawa
Biogeosciences, 18, 5351–5362, https://doi.org/10.5194/bg-18-5351-2021, https://doi.org/10.5194/bg-18-5351-2021, 2021
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Hydrogen and carbon isotope ratios of methane as well as the relevant biogeochemical parameters and microbial community compositions in hydrothermal plumes in the Okinawa Trough were observed. We succeeded in simultaneously determining hydrogen and carbon isotope fractionation factors associated with aerobic oxidation of methane in seawater (εH = 49.4 ± 5.0 ‰, εC = 5.2 ± 0.4 ‰) – the former being the first of its kind ever reported.
Nicolai Schleinkofer, David Evans, Max Wisshak, Janina Vanessa Büscher, Jens Fiebig, André Freiwald, Sven Härter, Horst R. Marschall, Silke Voigt, and Jacek Raddatz
Biogeosciences, 18, 4733–4753, https://doi.org/10.5194/bg-18-4733-2021, https://doi.org/10.5194/bg-18-4733-2021, 2021
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We have measured the chemical composition of the carbonate shells of the parasitic foraminifera Hyrrokkin sarcophaga in order to test if it is influenced by the host organism (bivalve or coral). We find that both the chemical and isotopic composition is influenced by the host organism. For example strontium is enriched in foraminifera that grew on corals, whose skeleton is built from aragonite, which is naturally enriched in strontium compared to the bivalves' calcite shell.
Lena Rohe, Traute-Heidi Anderson, Heinz Flessa, Anette Goeske, Dominika Lewicka-Szczebak, Nicole Wrage-Mönnig, and Reinhard Well
Biogeosciences, 18, 4629–4650, https://doi.org/10.5194/bg-18-4629-2021, https://doi.org/10.5194/bg-18-4629-2021, 2021
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This is the first experimental setup combining a complex set of methods (microbial inhibitors and isotopic approaches) to differentiate between N2O produced by fungi or bacteria during denitrification in three soils. Quantifying the fungal fraction with inhibitors was not successful due to large amounts of uninhibited N2O production. All successful methods suggested a small or missing fungal contribution. Artefacts occurring with microbial inhibition to determine N2O fluxes are discussed.
Inga Köhler, Raul E. Martinez, David Piatka, Achim J. Herrmann, Arianna Gallo, Michelle M. Gehringer, and Johannes A. C. Barth
Biogeosciences, 18, 4535–4548, https://doi.org/10.5194/bg-18-4535-2021, https://doi.org/10.5194/bg-18-4535-2021, 2021
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We investigated how high Fe(II) levels influence the O2 budget of a circum-neutral Fe(II)-rich spring and if a combined study of dissolved O (DO) and its isotopic composition can help assess this effect. We showed that dissolved Fe(II) can exert strong effects on the δ18ODO even though a constant supply of atmospheric O2 occurs. In the presence of photosynthesis, direct effects of Fe oxidation become masked. Critical Fe(II) concentrations indirectly control the DO by enhancing photosynthesis.
Owen A. Sherwood, Samuel H. Davin, Nadine Lehmann, Carolyn Buchwald, Evan N. Edinger, Moritz F. Lehmann, and Markus Kienast
Biogeosciences, 18, 4491–4510, https://doi.org/10.5194/bg-18-4491-2021, https://doi.org/10.5194/bg-18-4491-2021, 2021
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Pacific water flowing eastward through the Canadian Arctic plays an important role in redistributing nutrients to the northwest Atlantic Ocean. Using samples collected from northern Baffin Bay to the southern Labrador Shelf, we show that stable isotopic ratios in seawater nitrate reflect the fraction of Pacific to Atlantic water. These results provide a new framework for interpreting patterns of nitrogen isotopic variability recorded in modern and archival organic materials in the region.
Franziska Slotta, Lukas Wacker, Frank Riedel, Karl-Uwe Heußner, Kai Hartmann, and Gerhard Helle
Biogeosciences, 18, 3539–3564, https://doi.org/10.5194/bg-18-3539-2021, https://doi.org/10.5194/bg-18-3539-2021, 2021
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The African baobab is a challenging climate and environmental archive for its semi-arid habitat due to dating uncertainties and parenchyma-rich wood anatomy. Annually resolved F14C data of tree-ring cellulose (1941–2005) from a tree in Oman show the annual character of the baobab’s growth rings but were up to 8.8 % lower than expected for 1964–1967. Subseasonal δ13C and δ18O patterns reveal years with low average monsoon rain as well as heavy rainfall events from pre-monsoonal cyclones.
Peter M. J. Douglas, Emerald Stratigopoulos, Sanga Park, and Dawson Phan
Biogeosciences, 18, 3505–3527, https://doi.org/10.5194/bg-18-3505-2021, https://doi.org/10.5194/bg-18-3505-2021, 2021
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Hydrogen isotopes could be a useful tool to help resolve the geographic distribution of methane emissions from freshwater environments. We analyzed an expanded global dataset of freshwater methane hydrogen isotope ratios and found significant geographic variation linked to water isotopic composition. This geographic variability could be used to resolve changing methane fluxes from freshwater environments and provide more accurate estimates of the relative balance of global methane sources.
Veronica R. Rollinson, Julie Granger, Sydney C. Clark, Mackenzie L. Blanusa, Claudia P. Koerting, Jamie M. P. Vaudrey, Lija A. Treibergs, Holly C. Westbrook, Catherine M. Matassa, Meredith G. Hastings, and Craig R. Tobias
Biogeosciences, 18, 3421–3444, https://doi.org/10.5194/bg-18-3421-2021, https://doi.org/10.5194/bg-18-3421-2021, 2021
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We measured nutrients and the naturally occurring nitrogen (N) and oxygen (O) stable isotope ratios of nitrate discharged from a New England river over an annual cycle, to monitor N loading and identify dominant sources from the watershed. We uncovered a seasonality to loading and sources of N from the watershed. Seasonality in the nitrate isotope ratios also informed on N cycling, conforming to theoretical expectations of riverine nutrient cycling.
Zixun Chen, Xuejun Liu, Xiaoqing Cui, Yaowen Han, Guoan Wang, and Jiazhu Li
Biogeosciences, 18, 2859–2870, https://doi.org/10.5194/bg-18-2859-2021, https://doi.org/10.5194/bg-18-2859-2021, 2021
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δ13C in plants is a sensitive long-term indicator of physiological acclimatization. The present study suggests that precipitation change and increasing atmospheric N deposition have little impact on δ13C of H. ammodendron, a dominant plant in central Asian deserts, but affect its gas exchange. In addition, this study shows that δ13C of H. ammodendron could not indicate its water use efficiency (WUE), suggesting that whether δ13C of C4 plants indicates WUE is species-specific.
Petra Zahajská, Carolina Olid, Johanna Stadmark, Sherilyn C. Fritz, Sophie Opfergelt, and Daniel J. Conley
Biogeosciences, 18, 2325–2345, https://doi.org/10.5194/bg-18-2325-2021, https://doi.org/10.5194/bg-18-2325-2021, 2021
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The drivers of high accumulation of single-cell siliceous algae (diatoms) in a high-latitude lake have not been fully characterized before. We studied silicon cycling of the lake through water, radon, silicon, and stable silicon isotope balances. Results showed that groundwater brings 3 times more water and dissolved silica than the stream inlet. We demonstrate that groundwater discharge and low sediment deposition have driven the high diatom accumulation in the studied lake in the past century.
Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, and Gideon M. Henderson
Biogeosciences, 18, 1645–1671, https://doi.org/10.5194/bg-18-1645-2021, https://doi.org/10.5194/bg-18-1645-2021, 2021
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The South Atlantic near 40° S is one of the high-productivity and most dynamic nutrient regions in the oceans, but the sources and fluxes of trace elements (TEs) to this region remain unclear. This study investigates seawater Ra-228 and provides important constraints on ocean mixing and dissolved TE fluxes to this region. Vertical mixing is a more important source than aeolian or shelf inputs in this region, but particulate or winter deep-mixing inputs may be required to balance the TE budgets.
Zhongjie Yu and Emily M. Elliott
Biogeosciences, 18, 805–829, https://doi.org/10.5194/bg-18-805-2021, https://doi.org/10.5194/bg-18-805-2021, 2021
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In this study, we demonstrated distinct nitrogen isotope effects for nitric oxide (NO) production from major microbial and chemical NO sources in an agricultural soil. These results highlight characteristic bond-forming and breaking mechanisms associated with microbial and chemical NO production and implicate that simultaneous isotopic analyses of NO and nitrous oxide (N2O) can lead to unprecedented insights into the sources and processes controlling NO and N2O emissions from agricultural soils.
Daniel A. Frick, Rainer Remus, Michael Sommer, Jürgen Augustin, Danuta Kaczorek, and Friedhelm von Blanckenburg
Biogeosciences, 17, 6475–6490, https://doi.org/10.5194/bg-17-6475-2020, https://doi.org/10.5194/bg-17-6475-2020, 2020
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Silicon is taken up by some plants to increase structural stability and to develop stress resistance and is rejected by others. To explore the underlying mechanisms, we used the stable isotopes of silicon that shift in their relative abundance depending on the biochemical transformation involved. On species with a rejective (tomato, mustard) and active (wheat) uptake mechanism, grown in hydroculture, we found that the transport of silicic acid is controlled by the precipitation of biogenic opal.
Quentin Charbonnier, Julien Bouchez, Jérôme Gaillardet, and Éric Gayer
Biogeosciences, 17, 5989–6015, https://doi.org/10.5194/bg-17-5989-2020, https://doi.org/10.5194/bg-17-5989-2020, 2020
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The abundance and isotope composition of the trace metal barium (Ba) allows us to track and quantify nutrient cycling throughout the Amazon Basin. In particular, we show that the Ba biological fingerprint evolves from that of a strong net nutrient uptake in the mountainous area of the Andes towards efficient nutrient recycling on the plains of the Lower Amazon. Our study highlights the fact that the geochemical signature of rock-derived nutrients transported by the Amazon is scarred by life.
Ajinkya G. Deshpande, Thomas W. Boutton, Ayumi Hyodo, Charles W. Lafon, and Georgianne W. Moore
Biogeosciences, 17, 5639–5653, https://doi.org/10.5194/bg-17-5639-2020, https://doi.org/10.5194/bg-17-5639-2020, 2020
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Wetland forests in the southern USA are threatened by changing climate and human-induced pressures. We used tree ring widths and C isotopes as indicators of forest growth and physiological stress, respectively, and compared these to past climate data. We observed that vegetation growing in the drier patches is susceptible to stress, while vegetation growth and physiology in wetter patches is less sensitive to unfavorable environmental conditions, highlighting the importance of optimal wetness.
Dominika Lewicka-Szczebak, Maciej Piotr Lewicki, and Reinhard Well
Biogeosciences, 17, 5513–5537, https://doi.org/10.5194/bg-17-5513-2020, https://doi.org/10.5194/bg-17-5513-2020, 2020
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We present the first validation of N2O isotopic approaches for estimating N2O source pathways and N2O reduction. These approaches are widely used for tracing soil nitrogen cycling, but the results of these estimations are very uncertain. Here we report the results from parallel treatments allowing for precise validation of these approaches, and we propose the best strategies for results interpretation, including the new idea of an isotope model integrating three isotopic signatures of N2O.
Markus Raitzsch, Claire Rollion-Bard, Ingo Horn, Grit Steinhoefel, Albert Benthien, Klaus-Uwe Richter, Matthieu Buisson, Pascale Louvat, and Jelle Bijma
Biogeosciences, 17, 5365–5375, https://doi.org/10.5194/bg-17-5365-2020, https://doi.org/10.5194/bg-17-5365-2020, 2020
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The isotopic composition of boron in carbonate shells of marine unicellular organisms is a popular tool to estimate seawater pH. Usually, many shells need to be dissolved and measured for boron isotopes, but the information on their spatial distribution is lost. Here, we investigate two techniques that allow for measuring boron isotopes within single shells and show that they yield robust mean values but provide additional information on the heterogeneity within and between single shells.
Florian Einsiedl, Anja Wunderlich, Mathieu Sebilo, Ömer K. Coskun, William D. Orsi, and Bernhard Mayer
Biogeosciences, 17, 5149–5161, https://doi.org/10.5194/bg-17-5149-2020, https://doi.org/10.5194/bg-17-5149-2020, 2020
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Nitrate pollution of freshwaters and methane emissions into the atmosphere are crucial factors in deteriorating the quality of drinking water and in contributing to global climate change. Here, we report vertical concentration and stable isotope profiles of CH4, NO3-, NO2-, and NH4+ in the water column of Fohnsee (southern Bavaria, Germany) that may indicate linkages between nitrate-dependent anaerobic methane oxidation and the anaerobic oxidation of ammonium.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
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Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Ralf A. Oeser and Friedhelm von Blanckenburg
Biogeosciences, 17, 4883–4917, https://doi.org/10.5194/bg-17-4883-2020, https://doi.org/10.5194/bg-17-4883-2020, 2020
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We present a novel strategy to decipher the relative impact of biogenic and abiotic drivers of weathering. We parameterized the nutrient fluxes in four ecosystems along a climate and vegetation gradient situated on the Chilean Coastal Cordillera. We investigated how nutrient demand by plants drives weathering. We found that the increase in biomass nutrient demand is accommodated by faster nutrient recycling rather than an increase in the weathering–release rates.
Tito Arosio, Malin M. Ziehmer, Kurt Nicolussi, Christian Schlüchter, and Markus Leuenberger
Biogeosciences, 17, 4871–4882, https://doi.org/10.5194/bg-17-4871-2020, https://doi.org/10.5194/bg-17-4871-2020, 2020
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Stable isotopes in tree-ring cellulose are tools for climatic reconstructions, but interpretation is challenging due to nonclimate trends. We analyzed the tree-age trends in tree-ring isotopes of deciduous larch and evergreen cembran pine. Samples covering the whole Holocene were collected at the tree line in the Alps. For cambial ages over 100 years, we prove the absence of age trends in δD, δ18O, and δ13C for both species. For lower cambial ages, trends differ for each isotope and species.
Yuyang He, Xiaobin Cao, and Huiming Bao
Biogeosciences, 17, 4785–4795, https://doi.org/10.5194/bg-17-4785-2020, https://doi.org/10.5194/bg-17-4785-2020, 2020
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Different carbon sites in a large organic molecule have different isotope compositions. Different carbon sites may not have the chance to exchange isotopes at all. The lack of appreciation of this notion might be blamed for an unsettled debate on the thermodynamic state of an organism. Here we demonstrate using minerals, N2O, and acetic acid that the dearth of exchange among different carbon sites renders them as independent as if they were different elements in organic molecules.
Cited articles
Altabet, M. A.: Isotopic Tracers of the Marine Nitrogen Cycle: Present and Past, in: Marine Organic Matter: Biomarkers, Isotopes and DNA, edited by: Volkman, J. K., Springer, Berlin, Heidelberg, https://doi.org/10.1007/698_2_008, 251–293, 2006.
Altabet, M. A. and Francois, R.: Nitrogen isotope biogeochemistry of the Antarctic Polar Frontal Zone at 170° W, Deep-Sea Res. Pt. II, 48, 4247–4273, https://doi.org/10.1016/S0967-0645(01)00088-1, 2001.
Annett, A. L., Fitzsimmons, J. N., Séguret, M. J. M., Lagerström, M., Meredith, M. P., Schofield, O., and Sherrell, R. M.: Controls on dissolved and particulate iron distributions in surface waters of the Western Antarctic Peninsula shelf, Mar. Chem., 196, 81–97, https://doi.org/10.1016/j.marchem.2017.06.004, 2017.
Aoyama, M.: Global certified-reference-material- or reference-material-scaled nutrient gridded dataset GND13, Earth Syst. Sci. Data, 12, 487–499, https://doi.org/10.5194/essd-12-487-2020, 2020.
Ardelan, M. V., Holm-Hansen, O., Hewes, C. D., Reiss, C. S., Silva, N. S., Dulaiova, H., Steinnes, E., and Sakshaug, E.: Natural iron enrichment around the Antarctic Peninsula in the Southern Ocean, Biogeosciences, 7, 11–25, https://doi.org/10.5194/bg-7-11-2010, 2010.
Argo: Argo float data and metadata from Global Data Assembly Centre (Argo GDAC), SEANOE [data set], https://doi.org/10.17882/42182, 2025.
Armstrong, F. A. J., Stearns, C. R., and Strickland, J. D. H.: The measurement of upwelling and subsequent biological process by means of the Technicon Autoanalyzer® and associated equipment, Deep Sea Research and Oceanographic Abstracts, 14, 381–389, https://doi.org/10.1016/0011-7471(67)90082-4, 1967.
Arrigo, K. R.: Sea ice as a habitat for primary producers, in: Sea Ice, edited by: Thomas, D. N., John Wiley & Sons, Ltd, https://doi.org/10.1002/9781118778371.ch14, 352–369, 2017.
Arrigo, K. R., Worthen, D., Schnell, A., and Lizotte, M. P.: Primary production in Southern Ocean waters, J. Geophys. Res.-Oceans, 103, 15587–15600, https://doi.org/10.1029/98JC00930, 1998.
Arrigo, K. R., van Dijken, G. L., and Bushinsky, S.: Primary production in the Southern Ocean, 1997–2006, J. Geophys. Res.-Oceans, 113, C08004, https://doi.org/10.1029/2007JC004551, 2008.
Arteaga, L. A., Boss, E., Behrenfeld, M. J., Westberry, T. K., and Sarmiento, J. L.: Seasonal modulation of phytoplankton biomass in the Southern Ocean, Nat. Commun., 11, 5364, https://doi.org/10.1038/s41467-020-19157-2, 2020.
Behera, N., Swain, D., and Sil, S.: Effect of Antarctic sea ice on chlorophyll concentration in the Southern Ocean, Deep-Sea Res. Pt. II, 178, 104853, https://doi.org/10.1016/j.dsr2.2020.104853, 2020.
Bélanger, S., Ehn, J. K., and Babin, M.: Impact of sea ice on the retrieval of water-leaving reflectance, chlorophyll a concentration and inherent optical properties from satellite ocean color data, Remote Sens. Environ., 111, 51–68, https://doi.org/10.1016/j.rse.2007.03.013, 2007.
Boyd, P. W. and Ellwood, M. J.: The biogeochemical cycle of iron in the ocean, Nat. Geosci., 3, 675–682, https://doi.org/10.1038/ngeo964, 2010.
Braman, R. S. and Hendrix, S. A.: Nanogram nitrite and nitrate determination in environmental and biological materials by vanadium(III) reduction with chemiluminescence detection, Anal. Chem., 61, 2715–2718, https://doi.org/10.1021/ac00199a007, 1989.
Briggs, E. M., Martz, T. R., Talley, L. D., Mazloff, M. R., and Johnson, K. S.: Physical and Biological Drivers of Biogeochemical Tracers Within the Seasonal Sea Ice Zone of the Southern Ocean From Profiling Floats, J. Geophys. Res.-Oceans, 123, 746–758, https://doi.org/10.1002/2017JC012846, 2018.
Castro, C. G., Ríos, A. F., Doval, M. D., and Pérez, F. F.: Nutrient utilisation and chlorophyll distribution in the Atlantic sector of the Southern Ocean during Austral summer 1995–96, Deep-Sea Res. Pt. II, 49, 623–641, https://doi.org/10.1016/S0967-0645(01)00115-1, 2002.
Codispoti, L. A., Kelly, V., Thessen, A., Matrai, P., Suttles, S., Hill, V., Steele, M., and Light, B.: Synthesis of primary production in the Arctic Ocean: III. Nitrate and phosphate based estimates of net community production, Prog. Oceanogr., 110, 126–150, https://doi.org/10.1016/j.pocean.2012.11.006, 2013.
de Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A., and Iudicone, D.: Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology, J. Geophys. Res.-Oceans, 109, C12003, https://doi.org/10.1029/2004JC002378, 2004.
DiFiore, P. J., Sigman, D. M., Trull, T. W., Lourey, M. J., Karsh, K., Cane, G., and Ho, R.: Nitrogen isotope constraints on subantarctic biogeochemistry, J. Geophys. Res.-Oceans, 111, C08016, https://doi.org/10.1029/2005JC003216, 2006.
DiFiore, P. J., Sigman, D. M., and Dunbar, R. B.: Upper ocean nitrogen fluxes in the Polar Antarctic Zone: Constraints from the nitrogen and oxygen isotopes of nitrate, Geochem. Geophy. Geosy., 10, Q11016, https://doi.org/10.1029/2009GC002468, 2009.
DiFiore, P. J., Sigman, D. M., Karsh, K. L., Trull, T. W., Dunbar, R. B., and Robinson, R. S.: Poleward decrease in the isotope effect of nitrate assimilation across the Southern Ocean, Geophys. Res. Lett., 37, L17601, https://doi.org/10.1029/2010GL044090, 2010.
Fahrbach, E.: Cruise Report for R/V Polarstern Expedition 06AQANTX_7 on WOCE section SR04, CLIVAR and Carbon Hydrographic Data Office (CCHDO), https://cchdo.ucsd.edu/cruise/06AQANTX_7 (last access: May 2025), 1993.
Fan, T., Deser, C., and Schneider, D. P.: Recent Antarctic sea ice trends in the context of Southern Ocean surface climate variations since 1950, Geophys. Res. Lett., 41, 2419–2426, https://doi.org/10.1002/2014GL059239, 2014.
Flynn, R. F., Bornman, T. G., Burger, J. M., Smith, S., Spence, K. A. M., and Fawcett, S. E.: Summertime productivity and carbon export potential in the Weddell Sea, with a focus on the waters adjacent to Larsen C Ice Shelf, Biogeosciences, 18, 6031–6059, https://doi.org/10.5194/bg-18-6031-2021, 2021.
Franck, V. M., Brzezinski, M. A., Coale, K. H., and Nelson, D. M.: Iron and silicic acid concentrations regulate Si uptake north and south of the Polar Frontal Zone in the Pacific Sector of the Southern Ocean, Deep-Sea Res. Pt. II, 47, 3315–3338, https://doi.org/10.1016/S0967-0645(00)00070-9, 2000.
Frants, M., Gille, S. T., Hatta, M., Hiscock, W. T., Kahru, M., Measures, C. I., Greg Mitchell, B., and Zhou, M.: Analysis of horizontal and vertical processes contributing to natural iron supply in the mixed layer in southern Drake Passage, Deep-Sea Res. Pt. II, 90, 68–76, https://doi.org/10.1016/j.dsr2.2012.06.001, 2013.
Frey, D. I., Krechik, V. A., Morozov, E. G., Drozd, I. D., Gordey, A. S., Latushkin, A. A., Mekhova, O. S., Mukhametianov, R. Z., Murzina, S. A., Ostroumova, S. A., Ponomarev, V. I., Salyuk, P. A., Smirnova, D. A., Shutov, S. A., and Zuev, O. A.: Water Exchange between Deep Basins of the Bransfield Strait, Water, 14, 3193, https://doi.org/10.3390/w14203193, 2022.
Fripiat, F., Sigman, D. M., Fawcett, S. E., Rafter, P. A., Weigand, M. A., and Tison, J.-L.: New insights into sea ice nitrogen biogeochemical dynamics from the nitrogen isotopes, Global Biogeochem. Cy., 28, 115–130, https://doi.org/10.1002/2013GB004729, 2014.
Fripiat, F., Elskens, M., Trull, T. W., Blain, S., Cavagna, A.-J., Fernandez, C., Fonseca-Batista, D., Planchon, F., Raimbault, P., Roukaerts, A., and Dehairs, F.: Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean, Global Biogeochem. Cy., 29, 1929–1943, https://doi.org/10.1002/2014GB005051, 2015.
Fripiat, F., Martínez-García, A., Fawcett, S. E., Kemeny, P. C., Studer, A. S., Smart, S. M., Rubach, F., Oleynik, S., Sigman, D. M., and Haug, G. H.: The isotope effect of nitrate assimilation in the Antarctic Zone: Improved estimates and paleoceanographic implications, Geochim. Cosmochim. Ac., 247, 261–279, https://doi.org/10.1016/j.gca.2018.12.003, 2019.
Garcia, H. E., Boyer, T. P., Baranova, O. K., Locarnini, R. A., Mishonov, A. V., Grodsky, A., Paver, C. R., Weathers, K. W., Smolyar, I. V., Reagan, J. R., Seidov, D., and Zweng, M. M.: World Ocean Atlas 2018, NOAA National Centers for Environmental Information [data set], https://www.ncei.noaa.gov/data/oceans/woa/WOA18/ (last access: July 2023), 2019.
Goeyens, L., Tréguer, P., Baumann, M. E. M., Baeyens, W., and Dehairs, F.: The leading role of ammonium in the nitrogen uptake regime of Southern Ocean marginal ice zones, J. Marine Syst., 6, 345–361, https://doi.org/10.1016/0924-7963(94)00033-8, 1995.
Gonçalves-Araujo, R., De Souza, M. S., Tavano, V. M., and Garcia, C. A. E.: Influence of oceanographic features on spatial and interannual variability of phytoplankton in the Bransfield Strait, Antarctica, J. Marine Syst., 142, 1–15, https://doi.org/10.1016/j.jmarsys.2014.09.007, 2015.
Gordon, A. L., Mensch, M., Zhaoqian, D., Smethie, W. M., and de Bettencourt, J.: Deep and bottom water of the Bransfield Strait eastern and central basins, J. Geophys. Res., 105, 11337–11346, https://doi.org/10.1029/2000JC900030, 2000.
Hatta, M., Measures, C. I., Selph, K. E., Zhou, M., and Hiscock, W. T.: Iron fluxes from the shelf regions near the South Shetland Islands in the Drake Passage during the austral-winter 2006, Deep-Sea Res. Pt. II, 90, 89–101, https://doi.org/10.1016/j.dsr2.2012.11.003, 2013.
Huneke, W. G. C., Huhn, O., and Schröeder, M.: Water masses in the Bransfield Strait and adjacent seas, austral summer 2013, Polar Biol., 39, 789–798, https://doi.org/10.1007/s00300-016-1936-8, 2016.
Jiang, M., Measures, C. I., Barbeau, K. A., Charette, M. A., Gille, S. T., Hatta, M., Kahru, M., Mitchell, B. G., Naveira Garabato, A. C., Reiss, C., Selph, K., and Zhou, M.: Fe sources and transport from the Antarctic Peninsula shelf to the southern Scotia Sea, Deep-Sea Res. Pt. I, 150, 103060, https://doi.org/10.1016/j.dsr.2019.06.006, 2019.
Johnson, K. S. and Coletti, L. J.: In situ ultraviolet spectrophotometry for high resolution and long-term monitoring of nitrate, bromide and bisulfide in the ocean, Deep-Sea Res. Pt. I, 49, 1291–1305, https://doi.org/10.1016/S0967-0637(02)00020-1, 2002.
Johnson, K. S., Coletti, L. J., Jannasch, H. W., Sakamoto, C. M., Swift, D. D., and Riser, S. C.: Long-Term Nitrate Measurements in the Ocean Using the in situ Ultraviolet Spectrophotometer: Sensor Integration into the APEX Profiling Float, J. Atmos. Ocean. Tech., 30, 1854–1866, https://doi.org/10.1175/JTECH-D-12-00221.1, 2013.
Johnson, K. S., Plant, J. N., Coletti, L. J., Jannasch, H. W., Sakamoto, C. M., Riser, S. C., Swift, D. D., Williams, N. L., Boss, E., Haëntjens, N., Talley, L. D., and Sarmiento, J. L.: Biogeochemical sensor performance in the SOCCOM profiling float array, J. Geophys. Res.-Oceans, 122, 6416–6436, https://doi.org/10.1002/2017JC012838, 2017.
Johnson, K. S., Fassbender, A., Gray, A., Nicholson, D., Purkey, S., Riser, S. C., Takeshita, Y., Talley, L. D., Wijffels, S. E., Gilson, J., Grady, L. A., Guisewhite, N., Maurer, T. L., Parise, K., Plant, J. N., Robbins, P., Rupan, R. A., and Swift, D. D.: Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) and Global Ocean Biogeochemistry (GO-BGC) Biogeochemical-Argo Float Data Archive, Library digital collections UC San Diego [data set], https://doi.org/10.6075/J0SJ1KT8 (last access: May 2025), 2023.
Jones, J. M., Gille, S. T., Goosse, H., Abram, N. J., Canziani, P. O., Charman, D. J., Clem, K. R., Crosta, X., de Lavergne, C., Eisenman, I., England, M. H., Fogt, R. L., Frankcombe, L. M., Marshall, G. J., Masson-Delmotte, V., Morrison, A. K., Orsi, A. J., Raphael, M. N., Renwick, J. A., Schneider, D. P., Simpkins, G. R., Steig, E. J., Stenni, B., Swingedouw, D., and Vance, T. R.: Assessing recent trends in high-latitude Southern Hemisphere surface climate, Nat. Clim. Change, 6, 917–926, https://doi.org/10.1038/nclimate3103, 2016.
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., Gandin, L., Iredell, M., Saha, S., White, G., Woollen, J., Zhu, Y., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, J., Mo, K. C., Ropelewski, C., Wang, J., Leetmaa, A., Reynolds, R., Jenne, R., and Joseph, D.: The NCEP/NCAR 40-Year Reanalysis Project, B. Am. Meteorol. Soc., 77, 437–472, https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2, 1996.
Kemeny, P. C., Weigand, M. A., Zhang, R., Carter, B. R., Karsh, K. L., Fawcett, S. E., and Sigman, D. M.: Enzyme-level interconversion of nitrate and nitrite in the fall mixed layer of the Antarctic Ocean, Global Biogeochem. Cy., 30, 1069–1085, https://doi.org/10.1002/2015GB005350, 2016.
Key, R. M., Olsen, A., van Heuven, S., Lauvset, S. K., Velo, A., Lin, X., Schirnick, C., Kozyr, A., Tanhua, T., Hoppema, M., Jutterström, S., Steinfeldt, R., Jeansson, E., Ishii, M., Perez, F. F., and Suzuki, T.: Global Ocean Data Analysis Project, Version 2 (GLODAPv2), NOAA National Centers for Environmental Information [data set], https://doi.org/10.3334/CDIAC/OTG.NDP093_GLODAPv2 (last access: May 2025), 2015.
Klunder, M. B., Laan, P., De Baar, H. J. W., Middag, R., Neven, I., and Van Ooijen, J.: Dissolved Fe across the Weddell Sea and Drake Passage: impact of DFe on nutrient uptake, Biogeosciences, 11, 651–669, https://doi.org/10.5194/bg-11-651-2014, 2014.
Kwok, R. and Kacimi, S.: Three years of sea ice freeboard, snow depth, and ice thickness of the Weddell Sea from Operation IceBridge and CryoSat-2, The Cryosphere, 12, 2789–2801, https://doi.org/10.5194/tc-12-2789-2018, 2018.
La, H. S., Park, K., Chae, J. Y., Park, T., and Park, J.: Climatic factors and their robust evidences controlling phytoplankton biomass in the Bransfield Strait, Terr. Atmos. Ocean. Sci., 30, 821–830, https://doi.org/10.3319/TAO.2019.04.30.01, 2019.
Lannuzel, D., Vancoppenolle, M., van der Merwe, P., de Jong, J., Meiners, K. M., Grotti, M., Nishioka, J., and Schoemann, V.: Iron in sea ice: Review and new insights, Elementa: Science of the Anthropocene, 4, 000130, https://doi.org/10.12952/journal.elementa.000130, 2016.
Lauvset, S. K., Lange, N., Tanhua, T., Bittig, H. C., Olsen, A., Kozyr, A., Alin, S., Álvarez, M., Azetsu-Scott, K., Barbero, L., Becker, S., Brown, P. J., Carter, B. R., da Cunha, L. C., Feely, R. A., Hoppema, M., Humphreys, M. P., Ishii, M., Jeansson, E., Jiang, L.-Q., Jones, S. D., Lo Monaco, C., Murata, A., Müller, J. D., Pérez, F. F., Pfeil, B., Schirnick, C., Steinfeldt, R., Suzuki, T., Tilbrook, B., Ulfsbo, A., Velo, A., Woosley, R. J., and Key, R. M.: GLODAPv2.2022: the latest version of the global interior ocean biogeochemical data product, Earth Syst. Sci. Data, 14, 5543–5572, https://doi.org/10.5194/essd-14-5543-2022, 2022a.
Lauvset, S. K., Lange, N., Tanhua, T., Bittig, H. C., Olsen, A., Kozyr, A., Alin, S., Álvarez, M., Azetsu-Scott, K., Barbero, L., Becker, S., Brown, P. J., Carter, B. R., Cotrim da Cunha, L., Feely, R. A., Hoppema, M., Humphreys, M. P., Ishii, M., Jeansson, E., Jiang, L.-Q., Jones, S. D., Lo Monaco, C., Murata, A., Müller, J. D., Pérez, F. F., Pfeil, B., Schirnick, C., Steinfeldt, R., Suzuki, T., Tilbrook, B., Ulfsbo, A., Velo, A., Woosley, R. J., and Key, R. M.: Global Ocean Data Analysis Project version 2.2022 (GLODAPv2.2022) NCEI Accession 0257247, NOAA National Centers for Environmental Information [data set], https://doi.org/10.25921/1f4w-0t92 (last access: May 2025), 2022b.
Lavergne, T., Sørensen, A. M., Kern, S., Tonboe, R., Notz, D., Aaboe, S., Bell, L., Dybkjær, G., Eastwood, S., Gabarro, C., Heygster, G., Killie, M. A., Brandt Kreiner, M., Lavelle, J., Saldo, R., Sandven, S., and Pedersen, L. T.: Version 2 of the EUMETSAT OSI SAF and ESA CCI sea-ice concentration climate data records, The Cryosphere, 13, 49–78, https://doi.org/10.5194/tc-13-49-2019, 2019.
Lavergne, T., Sørensen, A., Tonboe, R., Strong, C., Kreiner, M., Saldo, R., Birkedal, A., Baordo, F., Rusin, J., Aspenes, T., and Eastwood, S.: Monitoring of Sea Ice Concentration, Area, and Extent in the polar regions: 40+ years of data from EUMETSAT OSI SAF and ESA CCI, IAF Global Space Conference on Climate Change, Oslo, Norway, 23–25 May 2023, https://doi.org/10.5281/zenodo.10014534, 2023.
Lewis, M. R., Hebert, D., Harrison, W. G., Platt, T., and Oakey, N. S.: Vertical Nitrate Fluxes in the Oligotrophic Ocean, Science, 234, 870–873, https://doi.org/10.1126/science.234.4778.870, 1986.
Lourey, M. J. and Trull, T. W.: Seasonal nutrient depletion and carbon export in the Subantarctic and Polar Frontal zones of the Southern Ocean south of Australia, J. Geophys. Res.-Oceans, 106, 31463–31487, https://doi.org/10.1029/2000JC000287, 2001.
Lourey, M. J., Trull, T. W., and Sigman, D. M.: Sensitivity of δ15N of nitrate, surface suspended and deep sinking particulate nitrogen to seasonal nitrate depletion in the Southern Ocean, Global Biogeochem. Cy., 17, 1081, https://doi.org/10.1029/2002GB001973, 2003.
MacIntyre, G., Plache, B., Lewis, M. R., Andrea, J., Feener, S., McLean, S. D., Johnson, K. S., Coletti, L. J., and Jannasch, H. W.: ISUS/SUNA nitrate measurements in networked ocean observing systems, in: OCEANS 2009, 26–29 October 2009, Biloxi, MS, United States of America, 7 pp., https://doi.org/10.23919/OCEANS.2009.5422251, 2009.
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, https://doi.org/10.1007/BF02374138, 1981.
Marshall, J. and Speer, K.: Closure of the meridional overturning circulation through Southern Ocean upwelling, Nat. Geosci., 5, 171–180, https://doi.org/10.1038/ngeo1391, 2012.
Maurer, T. L., Plant, J. N., and Johnson, K. S.: Delayed-Mode Quality Control of Oxygen, Nitrate, and pH Data on SOCCOM Biogeochemical Profiling Floats, Front. Mar. Sci., 8, 683207, https://doi.org/10.3389/fmars.2021.683207, 2021.
Mdutyana, M., Thomalla, S. J., Philibert, R., Ward, B. B., and Fawcett, S. E.: The Seasonal Cycle of Nitrogen Uptake and Nitrification in the Atlantic Sector of the Southern Ocean, Global Biogeochem. Cy., 34, e2019GB006363, https://doi.org/10.1029/2019GB006363, 2020.
Measures, C. I., Brown, M. T., Selph, K. E., Apprill, A., Zhou, M., Hatta, M., and Hiscock, W. T.: The influence of shelf processes in delivering dissolved iron to the HNLC waters of the Drake Passage, Antarctica, Deep-Sea Res. Pt. II, 90, 77–88, https://doi.org/10.1016/j.dsr2.2012.11.004, 2013.
Mengesha, S., Dehairs, F., Fiala, M., Elskens, M., and Goeyens, L.: Seasonal variation of phytoplankton community structure and nitrogen uptake regime in the Indian Sector of the Southern Ocean, Polar Biol., 20, 259–272, https://doi.org/10.1007/s003000050302, 1998.
Moffat, C. and Meredith, M.: Shelf–ocean exchange and hydrography west of the Antarctic Peninsula: a review, Philos. T. R. Soc. A, 376, 20170164, https://doi.org/10.1098/rsta.2017.0164, 2018.
Moline, M. and Prézelin, B.: Long-term monitoring and analyses of physical factors regulating variability in coastal Antarctic phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales, Mar. Ecol. Prog. Ser., 145, 143–160, https://doi.org/10.3354/meps145143, 1996.
Moore, J. K., Doney, S. C., Glover, D. M., and Fung, I. Y.: Iron cycling and nutrient-limitation patterns in surface waters of the World Ocean, Deep-Sea Res. Pt. II, 49, 463–507, https://doi.org/10.1016/S0967-0645(01)00109-6, 2002.
Moreau, S., Mostajir, B., Bélanger, S., Schloss, I. R., Vancoppenolle, M., Demers, S., and Ferreyra, G. A.: Climate change enhances primary production in the western Antarctic Peninsula, Glob. Change Biol., 21, 2191–2205, https://doi.org/10.1111/gcb.12878, 2015.
Moreau, S., Boyd, P. W., and Strutton, P. G.: Remote assessment of the fate of phytoplankton in the Southern Ocean sea-ice zone, Nat. Commun., 11, 3108, https://doi.org/10.1038/s41467-020-16931-0, 2020.
Morrison, A. K., Frölicher, T. L., and Sarmiento, J. L.: Upwelling in the Southern Ocean, Phys. Today, 68, 27–32, https://doi.org/10.1063/PT.3.2654, 2015.
Needoba, J. A. and Harrison, P. J.: Influence of low light and a light: dark cycle on NO
Needoba, J. A., Sigman, D. M., and Harrison, P. J.: The mechanism of isotope fractionation during algal nitrate assimilation as illuminated by the 15N/14N of intracellular nitrate, J. Phycol., 40, 517–522, https://doi.org/10.1111/j.1529-8817.2004.03172.x, 2004.
Nelson, D. M., Anderson, R. F., Barber, R. T., Brzezinski, M. A., Buesseler, K. O., Chase, Z., Collier, R. W., Dickson, M.-L., François, R., Hiscock, M. R., Honjo, S., Marra, J., Martin, W. R., Sambrotto, R. N., Sayles, F. L., and Sigmon, D. E.: Vertical budgets for organic carbon and biogenic silica in the Pacific sector of the Southern Ocean, 1996–1998, Deep-Sea Res. Pt. II, 49, 1645–1674, https://doi.org/10.1016/S0967-0645(02)00005-X, 2002.
Ohkouchi, N. and Takano, Y.: Organic Nitrogen: Sources, Fates, and Chemistry, in: Treatise on Geochemistry, vol. 12, edited by: Holland, H. D. and Turekian, K. K., Elsevier, https://doi.org/10.1016/B978-0-08-095975-7.01015-9, 251–289, 2014.
Olsen, A., Key, R. M., van Heuven, S., Lauvset, S. K., Velo, A., Lin, X., Schirnick, C., Kozyr, A., Tanhua, T., Hoppema, M., Jutterström, S., Steinfeldt, R., Jeansson, E., Ishii, M., Pérez, F. F., and Suzuki, T.: The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally consistent data product for the world ocean, Earth Syst. Sci. Data, 8, 297–323, https://doi.org/10.5194/essd-8-297-2016, 2016.
OSI SAF: Global Sea Ice Concentration Climate Data Record v3.0 – Multimission, EUMETSAT SAF on Ocean and Sea Ice [data set], https://doi.org/10.15770/EUM_SAF_OSI_0013, (last access: 7 September 2023), 2022a.
OSI SAF: Global Sea Ice Concentration Interim Climate Data Record Release 3 – DMSP, EUMETSAT SAF on Ocean and Sea Ice [data set], https://doi.org/10.15770/EUM_SAF_OSI_0014, (last access: 7 September 2023), 2022b.
Parkinson, C. L. and Cavalieri, D. J.: Antarctic sea ice variability and trends, 1979–2010, The Cryosphere, 6, 871–880, https://doi.org/10.5194/tc-6-871-2012, 2012.
Pellichero, V., Sallée, J.-B., Schmidtko, S., Roquet, F., and Charrassin, J.-B.: The ocean mixed layer under Southern Ocean sea-ice: Seasonal cycle and forcing, J. Geophys. Res.-Oceans, 122, 1608–1633, https://doi.org/10.1002/2016JC011970, 2017.
Pollard, R. T., Rhines, P. B., and Thompson, R. O. R. Y.: The deepening of the wind-Mixed layer, Geophysical Fluid Dynamics, 4, 381–404, https://doi.org/10.1080/03091927208236105, 1973.
Pondaven, P., Ragueneau, O., Tréguer, P., Hauvespre, A., Dezileau, L., and Reyss, J. L.: Resolving the `opal paradox' in the Southern Ocean, Nature, 405, 168–172, https://doi.org/10.1038/35012046, 2000.
Romanova, N. D., Mosharov, S. A., Vorobieva, O. V., and Bardyukova, E. V.: Quantitative and Productional Characteristics of Microplankton in the Powell Basin and Bransfield Strait in Summer, in: Antarctic Peninsula Region of the Southern Ocean: Oceanography and Ecology, edited by: Morozov, E. G., Flint, M. V., and Spiridonov, V. A., Springer International Publishing, Cham, https://doi.org/10.1007/978-3-030-78927-5_14, 197–207, 2021.
Russo, A. D. P. G., de Souza, M. S., Borges Mendes, C. R., Maria Tavano, V., and Eiras Garcia, C. A.: Spatial variability of photophysiology and primary production rates of the phytoplankton communities across the western Antarctic Peninsula in late summer 2013, Deep-Sea Res. Pt. II, 149, 99–110, https://doi.org/10.1016/j.dsr2.2017.09.021, 2018.
Sallée, J. B., Speer, K. G., and Rintoul, S. R.: Zonally asymmetric response of the Southern Ocean mixed-layer depth to the Southern Annular Mode, Nat. Geosci., 3, 273–279, https://doi.org/10.1038/ngeo812, 2010.
Sambrotto, R. N. and Mace, B. J.: Coupling of biological and physical regimes across the Antarctic Polar Front as reflected by nitrogen production and recycling, Deep-Sea Res. Pt. II, 47, 3339–3367, https://doi.org/10.1016/S0967-0645(00)00071-0, 2000.
Sangrà, P., Gordo, C., Hernández-Arencibia, M., Marrero-Díaz, A., Rodríguez-Santana, A., Stegner, A., Martínez-Marrero, A., Pelegrí, J. L., and Pichon, T.: The Bransfield current system, Deep-Sea Res. Pt. I, 58, 390–402, https://doi.org/10.1016/j.dsr.2011.01.011, 2011.
Savidge, G., Priddle, J., Gilpin, L. C., Bathmann, U., Murphy, E. J., Owens, N. J. P., Pollard, R. T., Turner, D. R., Veth, C., and Boyd, P.: An assessment of the role of the marginal ice zone in the carbon cycle of the Southern Ocean, Antarct. Sci., 8, 349–358, https://doi.org/10.1017/S0954102096000521, 1996.
Savoye, N., Dehairs, F., Elskens, M., Cardinal, D., Kopczyńska, E. E., Trull, T. W., Wright, S., Baeyens, W., and Griffiths, F. B.: Regional variation of spring N-uptake and new production in the Southern Ocean, Geophys. Res. Lett., 31, L03301, https://doi.org/10.1029/2003GL018946, 2004.
Servettaz, A. P. M.: Figure Notebook for “Sea ice and mixed layer depth influence on nitrate depletion and associated isotopic effects in the Drake Passage–Weddell Sea region, Southern Ocean” by Servettaz, A. P. M., Isaji, Y., Yoshikawa, C., Jang, Y., Khim, B.-K., Ryu, Y., Sigman, D. M., Ogawa, N. O., Jiménez-Espejo, F. J., and Ohkouchi, N., in Biogeosciences, 2025, Zenodo [code], https://doi.org/10.5281/zenodo.14958219, 2025.
Sherrell, R. M., Annett, A. L., Fitzsimmons, J. N., Roccanova, V. J., and Meredith, M. P.: A `shallow bathtub ring' of local sedimentary iron input maintains the Palmer Deep biological hotspot on the West Antarctic Peninsula shelf, Philos. T. R. Soc. A, 376, 20170171, https://doi.org/10.1098/rsta.2017.0171, 2018.
Sigman, D. M. and Fripiat, F.: Nitrogen Isotopes in the Ocean, in: Encyclopedia of Ocean Sciences, vol. 1, edited by: Cochran, J. K., Bokuniewicz, H. J., and Yager, P. L., Elsevier, https://doi.org/10.1016/B978-0-12-409548-9.11605-7, 263–278, 2019.
Sigman, D. M., Altabet, M. A., McCorkle, D. C., Francois, R., and Fischer, G.: The δ15N of nitrate in the southern ocean: Consumption of nitrate in surface waters, Global Biogeochem. Cy., 13, 1149–1166, https://doi.org/10.1029/1999GB900038, 1999.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M., and Böhlke, J. K.: A Bacterial Method for the Nitrogen Isotopic Analysis of Nitrate in Seawater and Freshwater, Anal. Chem., 73, 4145–4153, https://doi.org/10.1021/ac010088e, 2001.
Smart, S. M., Fawcett, S. E., Thomalla, S. J., Weigand, M. A., Reason, C. J. C., and Sigman, D. M.: Isotopic evidence for nitrification in the Antarctic winter mixed layer, Global Biogeochem. Cy., 29, 427–445, https://doi.org/10.1002/2014GB005013, 2015.
Smith, W. O. and Nelson, D. M.: Importance of Ice Edge Phytoplankton Production in the Southern Ocean, BioScience, 36, 251–257, https://doi.org/10.2307/1310215, 1986.
Soppa, M., Völker, C., and Bracher, A.: Diatom Phenology in the Southern Ocean: Mean Patterns, Trends and the Role of Climate Oscillations, Remote Sens.-Basel, 8, 420, https://doi.org/10.3390/rs8050420, 2016.
Spira, T., Swart, S., Giddy, I., and du Plessis, M.: The Observed Spatiotemporal Variability of Antarctic Winter Water, J. Geophys. Res.-Oceans, 129, e2024JC021017, https://doi.org/10.1029/2024JC021017, 2024.
Studer, A. S., Sigman, D. M., Martínez-García, A., Benz, V., Winckler, G., Kuhn, G., Esper, O., Lamy, F., Jaccard, S. L., Wacker, L., Oleynik, S., Gersonde, R., and Haug, G. H.: Antarctic Zone nutrient conditions during the last two glacial cycles: ANTARCTIC ZONE NUTRIENT CONDITIONS, Paleoceanography, 30, 845–862, https://doi.org/10.1002/2014PA002745, 2015.
Taylor, M. H., Losch, M., and Bracher, A.: On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach, J. Geophys. Res.-Oceans, 118, 63–75, https://doi.org/10.1029/2012JC008418, 2013.
Thomas, R. K., Fawcett, S. E., Forrer, H. J., Robinson, C. M., and Knapp, A. N.: Estimates of the Isotope Effect for Nitrate Assimilation in the Indian Sector of the Southern Ocean, J. Geophys. Res.-Oceans, 129, e2023JC020830, https://doi.org/10.1029/2023JC020830, 2024.
Thompson, A. F., Heywood, K. J., Thorpe, S. E., Renner, A. H. H., and Trasviña, A.: Surface Circulation at the Tip of the Antarctic Peninsula from Drifters, J. Phys. Oceanogr., 39, 3–26, https://doi.org/10.1175/2008JPO3995.1, 2009.
Uotila, P., Holland, P. R., Vihma, T., Marsland, S. J., and Kimura, N.: Is realistic Antarctic sea-ice extent in climate models the result of excessive ice drift?, Ocean Model., 79, 33–42, https://doi.org/10.1016/j.ocemod.2014.04.004, 2014.
Vernet, M., Martinson, D., Iannuzzi, R., Stammerjohn, S., Kozlowski, W., Sines, K., Smith, R., and Garibotti, I.: Primary production within the sea-ice zone west of the Antarctic Peninsula: I—Sea ice, summer mixed layer, and irradiance, Deep-Sea Res. Pt. II, 55, 2068–2085, https://doi.org/10.1016/j.dsr2.2008.05.021, 2008.
von Berg, L., Prend, C. J., Campbell, E. C., Mazloff, M. R., Talley, L. D., and Gille, S. T.: Weddell Sea Phytoplankton Blooms Modulated by Sea Ice Variability and Polynya Formation, Geophys. Res. Lett., 47, e2020GL087954, https://doi.org/10.1029/2020GL087954, 2020.
Vorrath, M.-E., Müller, J., Rebolledo, L., Cárdenas, P., Shi, X., Esper, O., Opel, T., Geibert, W., Muñoz, P., Haas, C., Kuhn, G., Lange, C. B., Lohmann, G., and Mollenhauer, G.: Sea ice dynamics in the Bransfield Strait, Antarctic Peninsula, during the past 240 years: a multi-proxy intercomparison study, Clim. Past, 16, 2459–2483, https://doi.org/10.5194/cp-16-2459-2020, 2020.
Wang, X. and Wu, Z.: Variability in Polar Sea Ice (1989–2018), IEEE Geosci. Remote S., 18, 1520–1524, https://doi.org/10.1109/LGRS.2020.3004257, 2021.
Wanninkhof, R., Johnson, K., Williams, N., Sarmiento, J., Riser, S., Briggs, E., Bushinsky, S., Carter, B., Dickson, A., Feely, R., Gray, A., Juranek, L., Key, R., Talley, L., Russel, J., and Verdy, A.: An Evaluation of pH and NO3 Sensor Data from SOCCOM Floats and their Utilization to Develop Ocean Inorganic Carbon Products, Digital Commons at The University of South Florida, 1342, 30 pp., https://digitalcommons.usf.edu/msc_facpub/1342/ (last access: April 2024), 2016.
Waser, N., Yin, K., Yu, Z., Tada, K., Harrison, P., Turpin, D., and Calvert, S.: Nitrogen isotope fractionation during nitrate, ammonium and urea uptake by marine diatoms and coccolithophores under various conditions of N availability, Mar. Ecol. Prog. Ser., 169, 29–41, https://doi.org/10.3354/meps169029, 1998.
Weigand, M. A., Foriel, J., Barnett, B., Oleynik, S., and Sigman, D. M.: Updates to instrumentation and protocols for isotopic analysis of nitrate by the denitrifier method, Rapid Commun. Mass Sp., 30, 1365–1383, https://doi.org/10.1002/rcm.7570, 2016.
Williams, G., Maksym, T., Wilkinson, J., Kunz, C., Murphy, C., Kimball, P., and Singh, H.: Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles, Nat. Geosci., 8, 61–67, https://doi.org/10.1038/ngeo2299, 2015.
Yoshikawa, C., Yamanaka, Y., and Nakatsuka, T.: An Ecosystem Model Including Nitrogen Isotopes: Perspectives on a Study of the Marine Nitrogen Cycle, J. Oceanogr., 61, 921–942, https://doi.org/10.1007/s10872-006-0010-5, 2005.
Yoshikawa, C., Ogawa, N. O., Chikaraishi, Y., Makabe, A., Matsui, Y., Sasai, Y., Wakita, M., Honda, M. C., Mino, Y., Aita, M. N., Fujiki, T., Nunoura, T., Harada, N., and Ohkouchi, N.: Nitrogen Isotopes of Sinking Particles Reveal the Seasonal Transition of the Nitrogen Source for Phytoplankton, Geophys. Res. Lett., 49, e2022GL098670, https://doi.org/10.1029/2022GL098670, 2022.
Yoshikawa, C., Shigemitsu, M., Yamamoto, A., Oka, A., and Ohkouchi, N.: A nitrogen isoscape of phytoplankton in the western North Pacific created with a marine nitrogen isotope model, Front. Mar. Sci., 11, 1294608, https://doi.org/10.3389/fmars.2024.1294608, 2024.
Zehr, J. P. and Capone, D. G.: Biogeography of N2 Fixation in the Surface Ocean, in: Marine Nitrogen Fixation, edited by: Zehr, J. P. and Capone, D. G., Springer International Publishing, Cham, https://doi.org/10.1007/978-3-030-67746-6_7, 117–141, 2021.
Zhou, X., Zhu, G., and Hu, S.: Influence of tides on mass transport in the Bransfield Strait and the adjacent areas, Antarctic, Polar Sci., 23, 100506, https://doi.org/10.1016/j.polar.2020.100506, 2020.
Short summary
Phytoplankton blooms occur after sea ice retreats in the Southern Ocean. In this study we investigate the influence of seasonal cycle of sea ice concentration on nitrate depletion, testing the hypothesis that meltwater release stabilizes the water column and favors nutrient utilization. We find that, at a regional scale, nitrate depletion and vertical mixing are weakly correlated with sea ice cycle. Nitrate depletion is rather linked to other oceanographic processes controlling mixing depth.
Phytoplankton blooms occur after sea ice retreats in the Southern Ocean. In this study we...
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