Articles | Volume 17, issue 19
https://doi.org/10.5194/bg-17-4919-2020
© 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-17-4919-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Effects of 238U variability and physical transport on water column 234Th downward fluxes in the coastal upwelling system off Peru
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Frédéric A. C. Le Moigne
Mediterranean Institute of Oceanography (UM 110, MIO), CNRS, IRD, Aix-Marseille Université, Marseille, France
Insa Rapp
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Jan Lüdke
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Beat Gasser
IAEA Environment Laboratories, 4 Quai Antoine 1er, 98000, Monaco
Marcus Dengler
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Volker Liebetrau
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Eric P. Achterberg
GEOMAR Helmholtz Center for Ocean Research Kiel, Wischhofstrasse 1–3,
24148 Kiel, Germany
Related authors
Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, https://doi.org/10.5194/bg-17-2263-2020, 2020
Short summary
Short summary
The production of N2O via nitrification and denitrification associated with low-O2 waters is a major source of oceanic N2O. We investigated the regulation and dynamics of these processes with respect to O2 and organic matter inputs. The transcription of the key nitrification gene amoA rapidly responded to changes in O2 and strongly correlated with N2O production rates. N2O production by denitrification was clearly stimulated by organic carbon, implying that its supply controls N2O production.
Ingeborg Bussmann, Eric P. Achterberg, Holger Brix, Nicolas Brüggemann, Götz Flöser, Claudia Schütze, and Philipp Fischer
Biogeosciences, 21, 3819–3838, https://doi.org/10.5194/bg-21-3819-2024, https://doi.org/10.5194/bg-21-3819-2024, 2024
Short summary
Short summary
Methane (CH4) is an important greenhouse gas and contributes to climate warming. However, the input of CH4 from coastal areas to the atmosphere is not well defined. Dissolved and atmospheric CH4 was determined at high spatial resolution in or above the North Sea. The atmospheric CH4 concentration was mainly influenced by wind direction. With our detailed study on the spatial distribution of CH4 fluxes we were able to provide a detailed and more realistic estimation of coastal CH4 fluxes.
Swantje Bastin, Aleksei Koldunov, Florian Schütte, Oliver Gutjahr, Marta Agnieszka Mrozowska, Tim Fischer, Radomyra Shevchenko, Arjun Kumar, Nikolay Koldunov, Helmuth Haak, Nils Brüggemann, Rebecca Hummels, Mia Sophie Specht, Johann Jungclaus, Sergey Danilov, Marcus Dengler, and Markus Jochum
EGUsphere, https://doi.org/10.5194/egusphere-2024-2281, https://doi.org/10.5194/egusphere-2024-2281, 2024
Short summary
Short summary
Vertical mixing is an important process e.g. for tropical sea surface temperature, but cannot be resolved by ocean models. Comparisons of mixing schemes and settings have usually been done with a single model, sometimes yielding conflicting results. We systematically compare two widely used schemes, TKE and KPP, with different parameter settings, in two different ocean models, and show that most effects from mixing scheme parameter changes are model dependent.
Jana Krause, Dustin Carroll, Juan Höfer, Jeremy Donaire, Eric Pieter Achterberg, Emilio Alarcón, Te Liu, Lorenz Meire, Kechen Zhu, and Mark James Hopwood
EGUsphere, https://doi.org/10.5194/egusphere-2023-2991, https://doi.org/10.5194/egusphere-2023-2991, 2024
Short summary
Short summary
Icebergs are a mechanism via which the cryosphere and ocean interact. Here we analyzed ice samples from both Arctic and Antarctic polar regions to assess the variability in the composition of calved ice. Our results show that low concentrations of nitrate and phosphate in ice are primarily atmospheric in origin, whereas sediments impart a low concentration of silica and modest concentrations of trace metals, especially iron and manganese.
Peter Brandt, Gaël Alory, Founi Mesmin Awo, Marcus Dengler, Sandrine Djakouré, Rodrigue Anicet Imbol Koungue, Julien Jouanno, Mareike Körner, Marisa Roch, and Mathieu Rouault
Ocean Sci., 19, 581–601, https://doi.org/10.5194/os-19-581-2023, https://doi.org/10.5194/os-19-581-2023, 2023
Short summary
Short summary
Tropical upwelling systems are among the most productive ecosystems globally. The tropical Atlantic upwelling undergoes a strong seasonal cycle that is forced by the wind. Local wind-driven upwelling and remote effects, particularly via the propagation of equatorial and coastal trapped waves, lead to an upward and downward movement of the nitracline. Turbulent mixing results in upward supply of nutrients. Here, we review the different physical processes responsible for biological productivity.
Kristian Spilling, Jonna Piiparinen, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Maria T. Camarena-Gómez, Elisabeth von der Esch, Martin A. Fischer, Markel Gómez-Letona, Nauzet Hernández-Hernández, Judith Meyer, Ruth A. Schmitz, and Ulf Riebesell
Biogeosciences, 20, 1605–1619, https://doi.org/10.5194/bg-20-1605-2023, https://doi.org/10.5194/bg-20-1605-2023, 2023
Short summary
Short summary
We carried out an enclosure experiment using surface water off Peru with different additions of oxygen minimum zone water. In this paper, we report on enzyme activity and provide data on the decomposition of organic matter. We found very high activity with respect to an enzyme breaking down protein, suggesting that this is important for nutrient recycling both at present and in the future ocean.
Mareike Körner, Peter Brandt, and Marcus Dengler
Ocean Sci., 19, 121–139, https://doi.org/10.5194/os-19-121-2023, https://doi.org/10.5194/os-19-121-2023, 2023
Short summary
Short summary
The coastal waters off Angola host a productive ecosystem. Surface waters at the coast are colder than further offshore. We find that surface heat fluxes warm the coastal region more strongly than the offshore region and cannot explain the differences. The influence of horizontal heat advection is minor on the surface temperature change. In contrast, ocean turbulence data suggest that cooling associated with vertical mixing is an important mechanism to explain the near-coastal cooling.
Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
Biogeosciences, 19, 295–312, https://doi.org/10.5194/bg-19-295-2022, https://doi.org/10.5194/bg-19-295-2022, 2022
Short summary
Short summary
Oxygen minimum zones in the ocean are characterized by enhanced carbon dioxide (CO2) levels and are being further acidified by increasing anthropogenic atmospheric CO2. Here we report CO2 system measurements in a mesocosm study offshore Peru during a rare coastal El Niño event to investigate how CO2 dynamics may respond to ongoing ocean deoxygenation. Our observations show that nitrogen limitation, productivity, and plankton community shift play an important role in driving the CO2 dynamics.
Léo Berline, Andrea Michelangelo Doglioli, Anne Petrenko, Stéphanie Barrillon, Boris Espinasse, Frederic A. C. Le Moigne, François Simon-Bot, Melilotus Thyssen, and François Carlotti
Biogeosciences, 18, 6377–6392, https://doi.org/10.5194/bg-18-6377-2021, https://doi.org/10.5194/bg-18-6377-2021, 2021
Short summary
Short summary
While the Ionian Sea is considered a nutrient-depleted and low-phytoplankton biomass area, it is a crossroad for water mass circulation. In the central Ionian Sea, we observed a strong contrast in particle distribution across a ~100 km long transect. Using remote sensing and Lagrangian simulations, we suggest that this contrast finds its origin in the long-distance transport of particles from the north, west and east of the Ionian Sea, where phytoplankton production was more intense.
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
Short summary
Short summary
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.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
Short summary
Short summary
Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Neil J. Wyatt, Angela Milne, Eric P. Achterberg, Thomas J. Browning, Heather A. Bouman, E. Malcolm S. Woodward, and Maeve C. Lohan
Biogeosciences, 18, 4265–4280, https://doi.org/10.5194/bg-18-4265-2021, https://doi.org/10.5194/bg-18-4265-2021, 2021
Short summary
Short summary
Using data collected during two expeditions to the South Atlantic Ocean, we investigated how the interaction between external sources and biological activity influenced the availability of the trace metals zinc and cobalt. This is important as both metals play essential roles in the metabolism and growth of phytoplankton and thus influence primary productivity of the oceans. We found seasonal changes in both processes that helped explain upper-ocean trace metal cycling.
Maximiliano J. Vergara-Jara, Mark J. Hopwood, Thomas J. Browning, Insa Rapp, Rodrigo Torres, Brian Reid, Eric P. Achterberg, and José Luis Iriarte
Ocean Sci., 17, 561–578, https://doi.org/10.5194/os-17-561-2021, https://doi.org/10.5194/os-17-561-2021, 2021
Short summary
Short summary
Ash from the Calbuco 2015 eruption spread across northern Patagonia, the SE Pacific and the SW Atlantic. In the Pacific, a phytoplankton bloom corresponded closely to the volcanic ash plume, suggesting that ash fertilized this region of the ocean. No such fertilization was found in the Atlantic where nutrients plausibly supplied by ash were likely already in excess of phytoplankton demand. In Patagonia, the May bloom was more intense than usual, but the mechanistic link to ash was less clear.
Philippe Massicotte, Rainer M. W. Amon, David Antoine, Philippe Archambault, Sergio Balzano, Simon Bélanger, Ronald Benner, Dominique Boeuf, Annick Bricaud, Flavienne Bruyant, Gwenaëlle Chaillou, Malik Chami, Bruno Charrière, Jing Chen, Hervé Claustre, Pierre Coupel, Nicole Delsaut, David Doxaran, Jens Ehn, Cédric Fichot, Marie-Hélène Forget, Pingqing Fu, Jonathan Gagnon, Nicole Garcia, Beat Gasser, Jean-François Ghiglione, Gaby Gorsky, Michel Gosselin, Priscillia Gourvil, Yves Gratton, Pascal Guillot, Hermann J. Heipieper, Serge Heussner, Stanford B. Hooker, Yannick Huot, Christian Jeanthon, Wade Jeffrey, Fabien Joux, Kimitaka Kawamura, Bruno Lansard, Edouard Leymarie, Heike Link, Connie Lovejoy, Claudie Marec, Dominique Marie, Johannie Martin, Jacobo Martín, Guillaume Massé, Atsushi Matsuoka, Vanessa McKague, Alexandre Mignot, William L. Miller, Juan-Carlos Miquel, Alfonso Mucci, Kaori Ono, Eva Ortega-Retuerta, Christos Panagiotopoulos, Tim Papakyriakou, Marc Picheral, Louis Prieur, Patrick Raimbault, Joséphine Ras, Rick A. Reynolds, André Rochon, Jean-François Rontani, Catherine Schmechtig, Sabine Schmidt, Richard Sempéré, Yuan Shen, Guisheng Song, Dariusz Stramski, Eri Tachibana, Alexandre Thirouard, Imma Tolosa, Jean-Éric Tremblay, Mickael Vaïtilingom, Daniel Vaulot, Frédéric Vaultier, John K. Volkman, Huixiang Xie, Guangming Zheng, and Marcel Babin
Earth Syst. Sci. Data, 13, 1561–1592, https://doi.org/10.5194/essd-13-1561-2021, https://doi.org/10.5194/essd-13-1561-2021, 2021
Short summary
Short summary
The MALINA oceanographic expedition was conducted in the Mackenzie River and the Beaufort Sea systems. The sampling was performed across seven shelf–basin transects to capture the meridional gradient between the estuary and the open ocean. The main goal of this research program was to better understand how processes such as primary production are influencing the fate of organic matter originating from the surrounding terrestrial landscape during its transition toward the Arctic Ocean.
Gerd Krahmann, Damian L. Arévalo-Martínez, Andrew W. Dale, Marcus Dengler, Anja Engel, Nicolaas Glock, Patricia Grasse, Johannes Hahn, Helena Hauss, Mark Hopwood, Rainer Kiko, Alexandra Loginova, Carolin R. Löscher, Marie Maßmig, Alexandra-Sophie Roy, Renato Salvatteci, Stefan Sommer, Toste Tanhua, and Hela Mehrtens
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2020-308, https://doi.org/10.5194/essd-2020-308, 2021
Preprint withdrawn
Short summary
Short summary
The project "Climate-Biogeochemistry Interactions in the Tropical Ocean" (SFB 754) was a multidisciplinary research project active from 2008 to 2019 aimed at a better understanding of the coupling between the tropical climate and ocean circulation and the ocean's oxygen and nutrient balance. On 34 research cruises, mainly in the Southeast Tropical Pacific and the Northeast Tropical Atlantic, 1071 physical, chemical and biological data sets were collected.
Stéphanie H. M. Jacquet, Dominique Lefèvre, Christian Tamburini, Marc Garel, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 2205–2212, https://doi.org/10.5194/bg-18-2205-2021, https://doi.org/10.5194/bg-18-2205-2021, 2021
Short summary
Short summary
We present new data concerning the relation between biogenic barium (Baxs, a tracer of carbon remineralization at mesopelagic depths), O2 consumption and prokaryotic heterotrophic production (PHP) in the Mediterranean Sea. The purpose of this paper is to improve our understanding of the relation between Baxs, PHP and O2 and to test the validity of the Dehairs transfer function in the Mediterranean Sea. This relation has never been tested in the Mediterranean Sea.
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
Short summary
Short summary
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.
Jan Lüdke, Marcus Dengler, Stefan Sommer, David Clemens, Sören Thomsen, Gerd Krahmann, Andrew W. Dale, Eric P. Achterberg, and Martin Visbeck
Ocean Sci., 16, 1347–1366, https://doi.org/10.5194/os-16-1347-2020, https://doi.org/10.5194/os-16-1347-2020, 2020
Short summary
Short summary
We analyse the intraseasonal variability of the alongshore circulation off Peru in early 2017, this circulation is very important for the supply of nutrients to the upwelling regime. The causes of this variability and its impact on the biogeochemistry are investigated. The poleward flow is strengthened during the observed time period, likely by a downwelling coastal trapped wave. The stronger current causes an increase in nitrate and reduces the deficit of fixed nitrogen relative to phosphorus.
Lennart Thomas Bach, Allanah Joy Paul, Tim Boxhammer, Elisabeth von der Esch, Michelle Graco, Kai Georg Schulz, Eric Achterberg, Paulina Aguayo, Javier Arístegui, Patrizia Ayón, Isabel Baños, Avy Bernales, Anne Sophie Boegeholz, Francisco Chavez, Gabriela Chavez, Shao-Min Chen, Kristin Doering, Alba Filella, Martin Fischer, Patricia Grasse, Mathias Haunost, Jan Hennke, Nauzet Hernández-Hernández, Mark Hopwood, Maricarmen Igarza, Verena Kalter, Leila Kittu, Peter Kohnert, Jesus Ledesma, Christian Lieberum, Silke Lischka, Carolin Löscher, Andrea Ludwig, Ursula Mendoza, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Joaquin Ortiz Cortes, Jonna Piiparinen, Claudia Sforna, Kristian Spilling, Sonia Sanchez, Carsten Spisla, Michael Sswat, Mabel Zavala Moreira, and Ulf Riebesell
Biogeosciences, 17, 4831–4852, https://doi.org/10.5194/bg-17-4831-2020, https://doi.org/10.5194/bg-17-4831-2020, 2020
Short summary
Short summary
The eastern boundary upwelling system off Peru is among Earth's most productive ocean ecosystems, but the factors that control its functioning are poorly constrained. Here we used mesocosms, moored ~ 6 km offshore Peru, to investigate how processes in plankton communities drive key biogeochemical processes. We show that nutrient and light co-limitation keep productivity and export at a remarkably constant level while stoichiometry changes strongly with shifts in plankton community structure.
Alexandra N. Loginova, Andrew W. Dale, Frédéric A. C. Le Moigne, Sören Thomsen, Stefan Sommer, David Clemens, Klaus Wallmann, and Anja Engel
Biogeosciences, 17, 4663–4679, https://doi.org/10.5194/bg-17-4663-2020, https://doi.org/10.5194/bg-17-4663-2020, 2020
Short summary
Short summary
We measured dissolved organic carbon (DOC), nitrogen (DON) and matter (DOM) optical properties in pore waters and near-bottom waters of the eastern tropical South Pacific off Peru. The difference between diffusion-driven and net fluxes of DOC and DON and qualitative changes in DOM optical properties suggested active microbial utilisation of the released DOM at the sediment–water interface. Our results suggest that the sediment release of DOM contributes to microbial processes in the area.
Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
Biogeosciences, 17, 3685–3704, https://doi.org/10.5194/bg-17-3685-2020, https://doi.org/10.5194/bg-17-3685-2020, 2020
Short summary
Short summary
We compare the cycling of Fe and Cd in sulfidic sediments of the Peruvian oxygen minimum zone. Due to the contrasting solubility of their sulfide minerals, the sedimentary Fe release and Cd burial fluxes covary with spatial and temporal distributions of H2S. Depending on the solubility of their sulfide minerals, sedimentary trace metal fluxes will respond differently to ocean deoxygenation/expansion of H2S concentrations, which may change trace metal stoichiometry of upwelling water masses.
Viena Puigcorbé, Pere Masqué, and Frédéric A. C. Le Moigne
Earth Syst. Sci. Data, 12, 1267–1285, https://doi.org/10.5194/essd-12-1267-2020, https://doi.org/10.5194/essd-12-1267-2020, 2020
Short summary
Short summary
The biological carbon pump is a mechanism by which the oceans capture atmospheric carbon dioxide thanks to microscopic marine algae. Quantifying its strength and efficiency is crucial to understand the global carbon budget and be able to forecast its trends. The radioactive pair 234Th : 238U has been extensively used for that purpose. This is a global compilation of carbon-to-234Th ratios (needed to convert the 234Th fluxes to carbon fluxes) that will contribute to improve our modeling efforts.
Mark J. Hopwood, Dustin Carroll, Thorben Dunse, Andy Hodson, Johnna M. Holding, José L. Iriarte, Sofia Ribeiro, Eric P. Achterberg, Carolina Cantoni, Daniel F. Carlson, Melissa Chierici, Jennifer S. Clarke, Stefano Cozzi, Agneta Fransson, Thomas Juul-Pedersen, Mie H. S. Winding, and Lorenz Meire
The Cryosphere, 14, 1347–1383, https://doi.org/10.5194/tc-14-1347-2020, https://doi.org/10.5194/tc-14-1347-2020, 2020
Short summary
Short summary
Here we compare and contrast results from five well-studied Arctic field sites in order to understand how glaciers affect marine biogeochemistry and marine primary production. The key questions are listed as follows. Where and when does glacial freshwater discharge promote or reduce marine primary production? How does spatio-temporal variability in glacial discharge affect marine primary production? And how far-reaching are the effects of glacial discharge on marine biogeochemistry?
Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, https://doi.org/10.5194/bg-17-2263-2020, 2020
Short summary
Short summary
The production of N2O via nitrification and denitrification associated with low-O2 waters is a major source of oceanic N2O. We investigated the regulation and dynamics of these processes with respect to O2 and organic matter inputs. The transcription of the key nitrification gene amoA rapidly responded to changes in O2 and strongly correlated with N2O production rates. N2O production by denitrification was clearly stimulated by organic carbon, implying that its supply controls N2O production.
Mark J. Hopwood, Nicolas Sanchez, Despo Polyviou, Øystein Leiknes, Julián Alberto Gallego-Urrea, Eric P. Achterberg, Murat V. Ardelan, Javier Aristegui, Lennart Bach, Sengul Besiktepe, Yohann Heriot, Ioanna Kalantzi, Tuba Terbıyık Kurt, Ioulia Santi, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1309–1326, https://doi.org/10.5194/bg-17-1309-2020, https://doi.org/10.5194/bg-17-1309-2020, 2020
Short summary
Short summary
Hydrogen peroxide, H2O2, is formed naturally in sunlight-exposed water by photochemistry. At high concentrations it is undesirable to biological cells because it is a stressor. Here, across a range of incubation experiments in diverse marine environments (Gran Canaria, the Mediterranean, Patagonia and Svalbard), we determine that two factors consistently affect the H2O2 concentrations irrespective of geographical location: bacteria abundance and experiment design.
Mark J. Hopwood, Carolina Santana-González, Julian Gallego-Urrea, Nicolas Sanchez, Eric P. Achterberg, Murat V. Ardelan, Martha Gledhill, Melchor González-Dávila, Linn Hoffmann, Øystein Leiknes, Juana Magdalena Santana-Casiano, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1327–1342, https://doi.org/10.5194/bg-17-1327-2020, https://doi.org/10.5194/bg-17-1327-2020, 2020
Short summary
Short summary
Fe is an essential micronutrient. Fe(III)-organic species are thought to account for > 99 % of dissolved Fe in seawater. Here we quantified Fe(II) during experiments in Svalbard, Gran Canaria, and Patagonia. Fe(II) was always a measurable fraction of dissolved Fe up to 65 %. Furthermore, when Fe(II) was allowed to decay in the dark, it remained present longer than predicted by kinetic equations, suggesting that Fe(II) is a more important fraction of dissolved Fe in seawater than widely recognized.
Marie Maßmig, Jan Lüdke, Gerd Krahmann, and Anja Engel
Biogeosciences, 17, 215–230, https://doi.org/10.5194/bg-17-215-2020, https://doi.org/10.5194/bg-17-215-2020, 2020
Short summary
Short summary
Little is known about the rates of bacterial element cycling in oxygen minimum zones (OMZs). We measured bacterial production and rates of extracellular hydrolytic enzymes at various in situ oxygen concentrations in the OMZ off Peru. Our field data show unhampered bacterial activity at low oxygen concentrations. Meanwhile bacterial degradation of organic matter substantially contributed to the formation of the OMZ.
Insa Rapp, Christian Schlosser, Jan-Lukas Menzel Barraqueta, Bernhard Wenzel, Jan Lüdke, Jan Scholten, Beat Gasser, Patrick Reichert, Martha Gledhill, Marcus Dengler, and Eric P. Achterberg
Biogeosciences, 16, 4157–4182, https://doi.org/10.5194/bg-16-4157-2019, https://doi.org/10.5194/bg-16-4157-2019, 2019
Short summary
Short summary
The availability of iron (Fe) affects phytoplankton growth in large parts of the ocean. Shelf sediments, particularly in oxygen minimum zones, are a major source of Fe and other essential micronutrients, such as cobalt (Co) and manganese (Mn). We observed enhanced concentrations of Fe, Co, and Mn corresponding with low oxygen concentrations along the Mauritanian shelf, indicating that the projected future decrease in oxygen concentrations may result in increases in Fe, Mn, and Co concentrations.
Nicolai Schleinkofer, Jacek Raddatz, André Freiwald, David Evans, Lydia Beuck, Andres Rüggeberg, and Volker Liebetrau
Biogeosciences, 16, 3565–3582, https://doi.org/10.5194/bg-16-3565-2019, https://doi.org/10.5194/bg-16-3565-2019, 2019
Short summary
Short summary
In this study we tried to correlate Na / Ca ratios from cold-water corals with environmental parameters such as salinity, temperature and pH. We do not observe a correlation between Na / Ca ratios and seawater salinity, but we do observe a strong correlation with temperature. Na / Ca data from warm-water corals (Porites spp.) and bivalves (Mytilus edulis) support this correlation, indicating that similar controls on the incorporation of sodium exist in these aragonitic organisms.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328, https://doi.org/10.5194/bg-16-2307-2019, https://doi.org/10.5194/bg-16-2307-2019, 2019
Short summary
Short summary
We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Alexandra N. Loginova, Sören Thomsen, Marcus Dengler, Jan Lüdke, and Anja Engel
Biogeosciences, 16, 2033–2047, https://doi.org/10.5194/bg-16-2033-2019, https://doi.org/10.5194/bg-16-2033-2019, 2019
Short summary
Short summary
High primary production in the Peruvian upwelling system is followed by rapid heterotrophic utilization of organic matter and supports the formation of one of the most intense oxygen minimum zones (OMZs) in the world. Here, we estimated vertical fluxes of oxygen and dissolved organic matter (DOM) from the surface to the OMZ. Our results suggest that DOM remineralization substantially reduces oxygen concentration in the upper water column and controls the shape of the upper oxycline.
Jan-Lukas Menzel Barraqueta, Jessica K. Klar, Martha Gledhill, Christian Schlosser, Rachel Shelley, Hélène F. Planquette, Bernhard Wenzel, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 16, 1525–1542, https://doi.org/10.5194/bg-16-1525-2019, https://doi.org/10.5194/bg-16-1525-2019, 2019
Short summary
Short summary
We used surface water dissolved aluminium concentrations collected in four different GEOTRACES cruises to determine atmospheric deposition fluxes to the ocean. We calculate atmospheric deposition fluxes for largely under-sampled regions of the Atlantic Ocean and thus provide new constraints for models of atmospheric deposition. The use of the MADCOW model is of major importance as dissolved aluminium is analysed within the GEOTRACES project at high spatial resolution.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, https://doi.org/10.5194/bg-16-979-2019, 2019
Short summary
Short summary
Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
Carolina Cisternas-Novoa, Frédéric A. C. Le Moigne, and Anja Engel
Biogeosciences, 16, 927–947, https://doi.org/10.5194/bg-16-927-2019, https://doi.org/10.5194/bg-16-927-2019, 2019
Short summary
Short summary
We investigate the composition and vertical fluxes of POM in two deep basins of the Baltic Sea (GB: Gotland Basin and LD: Landsort Deep). The two basins showed different O2 regimes resulting from the intrusion of oxygen-rich water from the North Sea that ventilated the deep waters in GB, but not in LD.
In GB, O2 intrusions lead to a high abundance of manganese oxides that aggregate with POM, altering its composition and vertical flux and contributing to a higher POC transfer efficiency in GB.
Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Catherine Schmechtig, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, and Patricia Zunino
Biogeosciences, 15, 7097–7109, https://doi.org/10.5194/bg-15-7097-2018, https://doi.org/10.5194/bg-15-7097-2018, 2018
Short summary
Short summary
The GEOVIDE cruise (GEOTRACES Section GA01) was conducted in the North Atlantic Ocean and Labrador Sea in May–June 2014. In this special issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 17 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Sonja Geilert, Christian Hensen, Mark Schmidt, Volker Liebetrau, Florian Scholz, Mechthild Doll, Longhui Deng, Annika Fiskal, Mark A. Lever, Chih-Chieh Su, Stefan Schloemer, Sudipta Sarkar, Volker Thiel, and Christian Berndt
Biogeosciences, 15, 5715–5731, https://doi.org/10.5194/bg-15-5715-2018, https://doi.org/10.5194/bg-15-5715-2018, 2018
Short summary
Short summary
Abrupt climate changes in Earth’s history might have been triggered by magmatic intrusions into organic-rich sediments, which can potentially release large amounts of greenhouse gases. In the Guaymas Basin, vigorous hydrothermal venting at the ridge axis and off-axis inactive vents show that magmatic intrusions are an effective way to release carbon but must be considered as very short-lived processes in a geological sense. These results need to be taken into account in future climate models.
Jan-Lukas Menzel Barraqueta, Christian Schlosser, Hélène Planquette, Arthur Gourain, Marie Cheize, Julia Boutorh, Rachel Shelley, Leonardo Contreira Pereira, Martha Gledhill, Mark J. Hopwood, François Lacan, Pascale Lherminier, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, https://doi.org/10.5194/bg-15-5271-2018, 2018
Short summary
Short summary
In the North Atlantic and Labrador Sea, low aerosol deposition and enhanced primary productivity control the dissolved aluminium (dAl) surface distribution, while remineralization of particles seems to control the distribution at depth. DAl in the ocean allows us to indirectly quantify the amount of dust deposited to a given region for a given period. Hence, the study of its distribution, cycling, sources, and sinks is of major importance to improve aerosol deposition models and climate models.
Christian Schlosser, Katrin Schmidt, Alfred Aquilina, William B. Homoky, Maxi Castrillejo, Rachel A. Mills, Matthew D. Patey, Sophie Fielding, Angus Atkinson, and Eric P. Achterberg
Biogeosciences, 15, 4973–4993, https://doi.org/10.5194/bg-15-4973-2018, https://doi.org/10.5194/bg-15-4973-2018, 2018
Short summary
Short summary
Iron (Fe) emanating from the South Georgia shelf system fuels large phytoplankton blooms downstream of the island. However, the actual supply mechanisms of Fe are unclear. We found that shelf-sediment-derived iron and iron released from Antarctic krill control the Fe distribution in the shelf waters around South Georgia. The majority of the Fe appears to be derived from recycling of Fe-enriched particles that are transported with the water masses into the bloom region.
Anja Engel, Hannes Wagner, Frédéric A. C. Le Moigne, and Samuel T. Wilson
Biogeosciences, 14, 1825–1838, https://doi.org/10.5194/bg-14-1825-2017, https://doi.org/10.5194/bg-14-1825-2017, 2017
Short summary
Short summary
To better understand the role of oxygen for the biological carbon pump, we studied particle fluxes through hypoxic waters in the eastern tropical North Atlantic. Attenuation of organic carbon fluxes over depth was lower than expected from seawater temperatures, indicating co-effects of oxygen concentration. Differences were observed for individual organic components, suggesting that future carbon export fluxes may depend on changes in surface ocean organic matter quality under global change.
Thomas Hornick, Lennart T. Bach, Katharine J. Crawfurd, Kristian Spilling, Eric P. Achterberg, Jason N. Woodhouse, Kai G. Schulz, Corina P. D. Brussaard, Ulf Riebesell, and Hans-Peter Grossart
Biogeosciences, 14, 1–15, https://doi.org/10.5194/bg-14-1-2017, https://doi.org/10.5194/bg-14-1-2017, 2017
Kristian Spilling, Kai G. Schulz, Allanah J. Paul, Tim Boxhammer, Eric P. Achterberg, Thomas Hornick, Silke Lischka, Annegret Stuhr, Rafael Bermúdez, Jan Czerny, Kate Crawfurd, Corina P. D. Brussaard, Hans-Peter Grossart, and Ulf Riebesell
Biogeosciences, 13, 6081–6093, https://doi.org/10.5194/bg-13-6081-2016, https://doi.org/10.5194/bg-13-6081-2016, 2016
Short summary
Short summary
We performed an experiment in the Baltic Sea in order to investigate the consequences of the increasing CO2 levels on biological processes in the free water mass. There was more accumulation of organic carbon at high CO2 levels. Surprisingly, this was caused by reduced loss processes (respiration and bacterial production) in a high-CO2 environment, and not by increased photosynthetic fixation of CO2. Our carbon budget can be used to better disentangle the effects of ocean acidification.
Allanah J. Paul, Eric P. Achterberg, Lennart T. Bach, Tim Boxhammer, Jan Czerny, Mathias Haunost, Kai-Georg Schulz, Annegret Stuhr, and Ulf Riebesell
Biogeosciences, 13, 3901–3913, https://doi.org/10.5194/bg-13-3901-2016, https://doi.org/10.5194/bg-13-3901-2016, 2016
Matthew P. Humphreys, Florence M. Greatrix, Eithne Tynan, Eric P. Achterberg, Alex M. Griffiths, Claudia H. Fry, Rebecca Garley, Alison McDonald, and Adrian J. Boyce
Earth Syst. Sci. Data, 8, 221–233, https://doi.org/10.5194/essd-8-221-2016, https://doi.org/10.5194/essd-8-221-2016, 2016
Short summary
Short summary
This paper reports the stable isotope composition of dissolved inorganic carbon in seawater for a transect from west to east across the North Atlantic Ocean. The results can be used to study oceanic uptake of anthropogenic carbon dioxide, and also to investigate the natural biological carbon pump. We also provide stable DIC isotope results for two batches of Dickson seawater CRMs to enable intercomparisons with other studies.
Monika Nausch, Lennart Thomas Bach, Jan Czerny, Josephine Goldstein, Hans-Peter Grossart, Dana Hellemann, Thomas Hornick, Eric Pieter Achterberg, Kai-Georg Schulz, and Ulf Riebesell
Biogeosciences, 13, 3035–3050, https://doi.org/10.5194/bg-13-3035-2016, https://doi.org/10.5194/bg-13-3035-2016, 2016
Short summary
Short summary
Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. Therefore, we conducted a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012. We compared the phosphorus dynamics in different mesocosm treatment
Lorenzo Rovelli, Marcus Dengler, Mark Schmidt, Stefan Sommer, Peter Linke, and Daniel F. McGinnis
Biogeosciences, 13, 1609–1620, https://doi.org/10.5194/bg-13-1609-2016, https://doi.org/10.5194/bg-13-1609-2016, 2016
R. Steinfeldt, J. Sültenfuß, M. Dengler, T. Fischer, and M. Rhein
Biogeosciences, 12, 7519–7533, https://doi.org/10.5194/bg-12-7519-2015, https://doi.org/10.5194/bg-12-7519-2015, 2015
Short summary
Short summary
The coastal upwelling systems, e.g. off Peru and Mauritania,
are key regions for the emissions of climate relevant trace gases
from the ocean into the atmosphere. Here, gases and nutrients are
transported into the ocean mixed layer from below. The upwelling velocities,
however, are too small to be measured directly.
We use the enhancement of helium-3 in upwelled
waters to quantify the vertical velocity,
which varies between 1.0 and 2.5 metres per day in the coastal regions.
A. J. Paul, L. T. Bach, K.-G. Schulz, T. Boxhammer, J. Czerny, E. P. Achterberg, D. Hellemann, Y. Trense, M. Nausch, M. Sswat, and U. Riebesell
Biogeosciences, 12, 6181–6203, https://doi.org/10.5194/bg-12-6181-2015, https://doi.org/10.5194/bg-12-6181-2015, 2015
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, and K. W. Fomba
Biogeosciences, 12, 5771–5792, https://doi.org/10.5194/bg-12-5771-2015, https://doi.org/10.5194/bg-12-5771-2015, 2015
Short summary
Short summary
A new technique to determine a size-fractionated global soil elemental emission inventory based on a global soil and mineralogical data set is introduced. Spatial variability of mineral dust elemental fractions (8 elements, e.g., Ca, Fe, Al) is identified on a global scale, particularly for Ca. The Ca/Al ratio ranged between 0.1 and 5.0 and is confirmed as an indicator of dust source regions by a global dust model. Total and soluble dust element fluxes into different ocean basins are estimated.
J.-C. Miquel, B. Gasser, J. Martín, C. Marec, M. Babin, L. Fortier, and A. Forest
Biogeosciences, 12, 5103–5117, https://doi.org/10.5194/bg-12-5103-2015, https://doi.org/10.5194/bg-12-5103-2015, 2015
Short summary
Short summary
POC fluxes obtained in the Eastern Beaufort Sea in August 2009 from drifting sediment traps were low (1-15 mg C m-2d-1), compared to long-term data which show higher but variable fluxes (10-40 mg C m-2d-1).
Composition of sinking particles, especially faecal pellets, highlighted the role of the zooplankton community and its trophic structure in the transition of carbon from the productive surface zone to the deep ocean. Carbon flux at this season results from a heterotrophic driven ecosystem.
M. P. Humphreys, E. P. Achterberg, A. M. Griffiths, A. McDonald, and A. J. Boyce
Earth Syst. Sci. Data, 7, 127–135, https://doi.org/10.5194/essd-7-127-2015, https://doi.org/10.5194/essd-7-127-2015, 2015
Short summary
Short summary
We present measurements of the stable carbon isotope composition of seawater dissolved inorganic carbon. The samples were collected during two research cruises in boreal summer 2012 in the northeastern Atlantic and Nordic Seas. The results can be used to investigate the marine carbon cycle, providing information about biological productivity and oceanic uptake of anthropogenic carbon dioxide.
A. W. Dale, S. Sommer, U. Lomnitz, I. Montes, T. Treude, V. Liebetrau, J. Gier, C. Hensen, M. Dengler, K. Stolpovsky, L. D. Bryant, and K. Wallmann
Biogeosciences, 12, 1537–1559, https://doi.org/10.5194/bg-12-1537-2015, https://doi.org/10.5194/bg-12-1537-2015, 2015
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
Short summary
Short summary
Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
T. Fischer, D. Banyte, P. Brandt, M. Dengler, G. Krahmann, T. Tanhua, and M. Visbeck
Biogeosciences, 10, 5079–5093, https://doi.org/10.5194/bg-10-5079-2013, https://doi.org/10.5194/bg-10-5079-2013, 2013
A. Forest, M. Babin, L. Stemmann, M. Picheral, M. Sampei, L. Fortier, Y. Gratton, S. Bélanger, E. Devred, J. Sahlin, D. Doxaran, F. Joux, E. Ortega-Retuerta, J. Martín, W. H. Jeffrey, B. Gasser, and J. Carlos Miquel
Biogeosciences, 10, 2833–2866, https://doi.org/10.5194/bg-10-2833-2013, https://doi.org/10.5194/bg-10-2833-2013, 2013
Related subject area
Biogeochemistry: Stable Isotopes & Other Tracers
Position-specific kinetic isotope effects for nitrous oxide: a new expansion of the Rayleigh model
Technical note: A Bayesian mixing model to unravel isotopic data and quantify trace gas production and consumption pathways for time series data – Time-resolved FRactionation And Mixing Evaluation (TimeFRAME)
Separating above-canopy CO2 and O2 measurements into their atmospheric and biospheric signatures
How long does carbon stay in a near-pristine central Amazon forest? An empirical estimate with radiocarbon
Errors associated with calculating the gross nitrification rates in forested catchments using the triple oxygen isotopic composition (Δ17O) of stream nitrate
Climatic controls on leaf wax hydrogen isotope ratios in terrestrial and marine sediments along a hyperarid-to-humid gradient
Fractionation of stable carbon isotopes during microbial propionate consumption in anoxic rice paddy soils
Sources and sinks of carbonyl sulfide inferred from tower and mobile atmospheric observations in the Netherlands
Downpour dynamics: outsized impacts of storm events on unprocessed atmospheric nitrate export in an urban watershed
The hidden role of dissolved organic carbon in the biogeochemical cycle of carbon in modern redox-stratified lakes
Biogeochemical processes captured by carbon isotopes in redox-stratified water columns: a comparative study of four modern stratified lakes along an alkalinity gradient
Partitioning of carbon export in the euphotic zone of the oligotrophic South China Sea
Determination of respiration and photosynthesis fractionation factors for atmospheric dioxygen inferred from a vegetation–soil–atmosphere analogue of the terrestrial biosphere in closed chambers
Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies
Neodymium budget in the Mediterranean Sea: evaluating the role of atmospheric dusts using a high-resolution dynamical-biogeochemical model
Nitrate isotope investigations reveal future impacts of climate change on nitrogen inputs and cycling in Arctic fjords: Kongsfjorden and Rijpfjorden (Svalbard)
Mineralization of autochthonous particulate organic carbon is a fast channel of organic matter turnover in Germany's largest drinking water reservoir
Carbon isotopic ratios of modern C3 and C4 vegetation on the Indian peninsula and changes along the plant–soil–river continuum – implications for vegetation reconstructions
Controls on nitrite oxidation in the upper Southern Ocean: insights from winter kinetics experiments in the Indian sector
Tracing the source of nitrate in a forested stream showing elevated concentrations during storm events
Intra-skeletal variability in phosphate oxygen isotope composition reveals regional heterothermies in marine vertebrates
Isotopic differences in soil–plant–atmosphere continuum composition and control factors of different vegetation zones on the northern slope of the Qilian Mountains
An analysis of the variability in δ13C in macroalgae from the Gulf of California: indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation
Summertime productivity and carbon export potential in the Weddell Sea, with a focus on the waters adjacent to Larsen C Ice Shelf
Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)
Hydrogen and carbon isotope fractionation factors of aerobic methane oxidation in deep-sea water
Host-influenced geochemical signature in the parasitic foraminifera Hyrrokkin sarcophaga
Comparing modified substrate-induced respiration with selective inhibition (SIRIN) and N2O isotope approaches to estimate fungal contribution to denitrification in three arable soils under anoxic conditions
How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Fürth, Germany
Stable isotope ratios in seawater nitrate reflect the influence of Pacific water along the northwest Atlantic margin
High-resolution 14C bomb peak dating and climate response analyses of subseasonal stable isotope signals in wood of the African baobab – a case study from Oman
Geographic variability in freshwater methane hydrogen isotope ratios and its implications for global isotopic source signatures
Seasonality of nitrogen sources, cycling, and loading in a New England river discerned from nitrate isotope ratios
Evaluating the response of δ13C in Haloxylon ammodendron, a dominant C4 species in Asian desert ecosystems, to water and nitrogen addition as well as the availability of its δ13C as an indicator of water use efficiency
Modern silicon dynamics of a small high-latitude subarctic lake
Radium-228-derived ocean mixing and trace element inputs in the South Atlantic
Nitrogen isotopic fractionations during nitric oxide production in an agricultural soil
Silicon uptake and isotope fractionation dynamics by crop species
Barium stable isotopes as a fingerprint of biological cycling in the Amazon River basin
Bottomland hardwood forest growth and stress response to hydroclimatic variation: evidence from dendrochronology and tree ring Δ13C values
N2O isotope approaches for source partitioning of N2O production and estimation of N2O reduction – validation with the 15N gas-flux method in laboratory and field studies
Technical note: Single-shell δ11B analysis of Cibicidoides wuellerstorfi using femtosecond laser ablation MC-ICPMS and secondary ion mass spectrometry
Biogeochemical evidence of anaerobic methane oxidation and anaerobic ammonium oxidation in a stratified lake using stable isotopes
Do degree and rate of silicate weathering depend on plant productivity?
Alpine Holocene tree-ring dataset: age-related trends in the stable isotopes of cellulose show species-specific patterns
Ideas and perspectives: The same carbon behaves like different elements – an insight into position-specific isotope distributions
Seasonal dynamics of the COS and CO2 exchange of a managed temperate grassland
Leaf-scale quantification of the effect of photosynthetic gas exchange on Δ17O of atmospheric CO2
The stable carbon isotope signature of methane produced by saprotrophic fungi
Understanding the effects of early degradation on isotopic tracers: implications for sediment source attribution using compound-specific isotope analysis (CSIA)
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Ingrid Chanca, Ingeborg Levin, Susan Trumbore, Kita Macario, Jost Lavric, Carlos Alberto Quesada, Alessandro Carioca de Araújo, Cléo Quaresma Dias Júnior, Hella van Asperen, Samuel Hammer, and Carlos Sierra
EGUsphere, https://doi.org/10.5194/egusphere-2024-883, https://doi.org/10.5194/egusphere-2024-883, 2024
Short summary
Short summary
Assessing the net carbon (C) budget of the Amazon entails considering the magnitude and timing of C absorption and losses through respiration (transit time of C). Radiocarbon-based estimates of the transit time of C in the Amazon Tall Tower Observatory (ATTO) suggest a doubling of the transit time from 6 ± 2 years and 18 ± 5 years (October 2019 and December 2021, respectively). This variability indicates that only a fraction of newly fixed C can be stored for decades or longer.
Weitian Ding, Urumu Tsunogai, and Fumiko Nakagawa
EGUsphere, https://doi.org/10.5194/egusphere-2023-2753, https://doi.org/10.5194/egusphere-2023-2753, 2023
Short summary
Short summary
Past studies have used the Δ17O of stream nitrate to estimate the GNR in each forested catchment by approximating the Δ17O value of soil nitrate to be equal to that of stream nitrate. Based on formulaic inference and simulated 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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Felix M. Spielmann, Albin Hammerle, Florian Kitz, Katharina Gerdel, and Georg Wohlfahrt
Biogeosciences, 17, 4281–4295, https://doi.org/10.5194/bg-17-4281-2020, https://doi.org/10.5194/bg-17-4281-2020, 2020
Short summary
Short summary
Carbonyl sulfide (COS) can be used as a proxy for plant photosynthesis on an ecosystem scale. However, the relationships between COS and CO2 fluxes and their dependence on daily to seasonal changes in environmental drivers are still poorly understood. We examined COS and CO2 ecosystem fluxes above an agriculturally used mountain grassland for 6 months. Harvesting of the grassland disturbed the otherwise stable COS-to-CO2 uptake ratio. We even found the canopy to release COS during those times.
Getachew Agmuas Adnew, Thijs L. Pons, Gerbrand Koren, Wouter Peters, and Thomas Röckmann
Biogeosciences, 17, 3903–3922, https://doi.org/10.5194/bg-17-3903-2020, https://doi.org/10.5194/bg-17-3903-2020, 2020
Short summary
Short summary
We measured the effect of photosynthesis, the largest flux in the carbon cycle, on the triple oxygen isotope composition of atmospheric CO2 at the leaf level during gas exchange using three plant species. The main factors that limit the impact of land vegetation on the triple oxygen isotope composition of atmospheric CO2 are identified, characterized and discussed. The effect of photosynthesis on the isotopic composition of CO2 is commonly quantified as discrimination (ΔA).
Moritz Schroll, Frank Keppler, Markus Greule, Christian Eckhardt, Holger Zorn, and Katharina Lenhart
Biogeosciences, 17, 3891–3901, https://doi.org/10.5194/bg-17-3891-2020, https://doi.org/10.5194/bg-17-3891-2020, 2020
Short summary
Short summary
Fungi have recently been identified to produce the greenhouse gas methane. Here, we investigated the stable carbon isotope values of methane produced by saprotrophic fungi. Our results show that stable isotope values of methane from fungi are dependent on the fungal species and the metabolized substrate. They cover a broad range and overlap with stable carbon isotope values of methane reported for methanogenic archaea, the thermogenic degradation of organic matter, and other eukaryotes.
Pranav Hirave, Guido L. B. Wiesenberg, Axel Birkholz, and Christine Alewell
Biogeosciences, 17, 2169–2180, https://doi.org/10.5194/bg-17-2169-2020, https://doi.org/10.5194/bg-17-2169-2020, 2020
Short summary
Short summary
Sediment input into water bodies is a prominent threat to freshwater ecosystems. We tested the stability of tracers employed in freshwater sediment tracing based on compound-specific isotope analysis during early degradation in soil. While bulk δ13C values showed no stability, δ13C values of plant-derived fatty acids and n-alkanes were stably transferred to the soil without soil particle size dependency after an early degradation in organic horizons, thus indicating their suitability as tracers.
Cited articles
Abernathey, R. P. and Marshall, J.: Global surface eddy diffusivities
derived from satellite altimetry, J. Geophys. Res.-Oceans,
118, 901-916, https://doi.org/10.1002/jgrc.20066, 2013.
Anderson, R. F., Fleisher, M. Q., and LeHuray, A. P.: Concentration,
oxidation state, and particulate flux of uranium in the Black Sea,
Geochim. Cosmochim. Ac., 53, 2215–2224, https://doi.org/10.1016/0016-7037(89)90345-1, 1989.
Arthur, M. A., Dean, W. E., and Laarkamp, K.: Organic carbon accumulation
and preservation in surface sediments on the Peru margin, Chem. Geol.,
152, 273–286, https://doi.org/10.1016/S0009-2541(98)00120-X,
1998.
Bacon, M., Cochran, J., Hirschberg, D., Hammar, T., and Fleer, A.: Export
flux of carbon at the equator during the EqPac time-series cruises estimated
from 234Th measurements, Deep-Sea Res. Pt. II, 43, 1133–1153, https://doi.org/10.1016/0967-0645(96)00016-1, 1996.
Barnes, C. and Cochran, J.: Uranium removal in oceanic sediments and the
oceanic U balance, Earth Planet. Sc. Lett., 97, 94–101,
https://doi.org/10.1016/0012-821X(90)90101-3, 1990.
Barnes, C. E. and Cochran, J. K.: Geochemistry of uranium in Black Sea
sediments, Deep.-Sea Res., 38,
S1237–S1254, https://doi.org/10.1016/S0198-0149(10)80032-9,
1991.
Barnes, C. E. and Cochran, J. K.: Uranium geochemistry in estuarine
sediments: Controls on removal and release processes, Geochim. Cosmochim. Ac., 57, 555–569, https://doi.org/10.1016/0016-7037(93)90367-6, 1993.
Benitez-Nelson, C. R., Buesseler, K. O., and Crossin, G.: Upper ocean carbon
export, horizontal transport, and vertical eddy diffusivity in the
southwestern Gulf of Maine, Cont. Shelf. Res., 20, 707–736,
https://doi.org/10.1016/S0278-4343(99)00093-X, 2000.
Bentamy, A. and Croize-Fillon: Gridded surface wind fields from Metop/ASCAT
measurements, Int. J. Remote Sens., 33, 1729–1754,
https://doi.org/10.1080/01431161.2011.600348, 2010.
Bewers, J. and Yeats, P.: Oceanic residence times of trace metals, Nature,
268, 595–598, https://doi.org/10.1038/268595a0, 1977.
Bhat, S., Krishnaswamy, S., Lal, D., and Moore, W.: 234Th ∕238U
ratios in the ocean, Earth Planet. Sc. Lett., 5, 483–491,
https://doi.org/10.1016/S0012-821X(68)80083-4, 1968.
Black, E. E., Buesseler, K. O., Pike, S. M., and Lam, P. J.: 234Th as a
tracer of particulate export and remineralization in the southeastern
tropical Pacific, Mar. Chem., 201, 35–50, https://doi.org/10.1016/j.marchem.2017.06.009, 2018.
Black, E. E., Lam, P. J., Lee, J. M., and Buesseler, K. O.: Insights From
the 238U–234Th Method Into the Coupling of Biological Export and
the Cycling of Cadmium, Cobalt, and Manganese in the Southeast Pacific
Ocean, Global Biogeochem. Cy., 33, 15–36, https://doi.org/10.1029/2018GB005985, 2019.
Böning, P., Brumsack, H.-J., Böttcher, M. E., Schnetger, B., Kriete,
C., Kallmeyer, J., and Borchers, S. L.: Geochemistry of Peruvian
near-surface sediments, Geochim. Cosmochim. Ac., 68, 4429–4451,
https://doi.org/10.1016/j.gca.2004.04.027, 2004.
Buckingham, C. E., Lucas, N. S., Belcher, S. E., Rippeth, T. P., Grant, A.
L. M., Le Sommer, J., Ajayi, A. O., and Naveira Garabato, A. C.: The
Contribution of Surface and Submesoscale Processes to Turbulence in the Open
Ocean Surface Boundary Layer, J. Adv. Model. Earth Sy.,
11, 4066–4094, https://doi.org/10.1029/2019MS001801, 2019.
Buesseler, K., Ball, L., Andrews, J., Benitez-Nelson, C., Belastock, R.,
Chai, F., and Chao, Y.: Upper ocean export of particulate organic carbon in
the Arabian Sea derived from thorium-234, Deep-Sea Res. Pt. II, 45, 2461–2487, https://doi.org/10.1016/S0967-0645(98)80022-2, 1998.
Buesseler, K. O., Bacon, M. P., Cochran, J. K., and Livingston, H. D.:
Carbon and nitrogen export during the JGOFS North Atlantic Bloom Experiment
estimated from 234Th : 238U disequilibria, Deep.-Sea Res., 39, 1115–1137, https://doi.org/10.1016/0198-0149(92)90060-7, 1992.
Buesseler, K. O., Andrews, J. A., Hartman, M. C., Belastock, R., and Chai,
F.: Regional estimates of the export flux of particulate organic carbon
derived from thorium-234 during the JGOFS EqPac program, Deep-Sea Res. Pt. II, 42, 777–804, https://doi.org/10.1016/0967-0645(95)00043-P, 1995.
Buesseler, K. O., Andrews, J., Pike, S. M., Charette, M. A., Goldson, L. E.,
Brzezinski, M. A., and Lance, V.: Particle export during the southern ocean
iron experiment (SOFeX), Limnol. Oceanogr., 50, 311–327, https://doi.org/10.4319/lo.2005.50.1.0311, 2005.
Buesseler, K. O., Benitez-Nelson, C. R., Moran, S., Burd, A., Charette, M.,
Cochran, J. K., Coppola, L., Fisher, N., Fowler, S., and Gardner, W.: An
assessment of particulate organic carbon to thorium-234 ratios in the ocean
and their impact on the application of 234Th as a POC flux proxy,
Mar. Chem., 100, 213–233, https://doi.org/10.1016/j.marchem.2005.10.013, 2006.
Buesseler, K. O. and Boyd, P. W.: Shedding light on processes that control
particle export and flux attenuation in the twilight zone of the open ocean,
Limnol. Oceanogr., 54, 1210–1232, https://doi.org/10.4319/lo.2009.54.4.1210, 2009.
Cai, P., Chen, W., Dai, M., Wan, Z., Wang, D., Li, Q., Tang, T., and Lv, D.:
A high-resolution study of particle export in the southern South China Sea
based on 234Th : 238U disequilibrium, J. Geophys. Res.-Oceans, 113, C04019, https://doi.org/10.1029/2007JC004268,
2008.
Charette, M. A., Moran, S. B., Pike, S. M., and Smith, J. N.: Investigating
the carbon cycle in the Gulf of Maine using the natural tracer thorium 234,
J. Geophys. Res.-Oceans, 106, 11553–11579, https://doi.org/10.1029/1999JC000277, 2001.
Charette, M. A., Gonneea, M. E., Morris, P. J., Statham, P., Fones, G.,
Planquette, H., Salter, I., and Garabato, A. N.: Radium isotopes as tracers
of iron sources fueling a Southern Ocean phytoplankton bloom, Deep-Sea Res. Pt. II, 54, 1989–1998, https://doi.org/10.1016/j.dsr2.2007.06.003, 2007.
Chen, J., Edwards, R. L., and Wasserburg, G. J.: 238U, 234U and
232Th in seawater, Earth Planet. Sc. Lett., 80, 241–251,
https://doi.org/10.1016/0012-821X(86)90108-1, 1986.
Coale, K. H. and Bruland, K. W.: 234Th: 238U disequilibria within
the California Current 1, Limnol. Oceanogr., 30, 22–33, https://doi.org/10.4319/lo.1985.30.1.0022, 1985.
Coale, K. H. and Bruland, K. W.: Oceanic stratified euphotic zone as
elucidated by 234Th: 238U disequilibria 1, Limnol. Oceanogr., 32, 189–200, https://doi.org/10.4319/lo.1987.32.1.0189, 1987.
Cochran, J. and Masqué, P.: Short-lived U/Th series radionuclides in
the ocean: tracers for scavenging rates, export fluxes and particle
dynamics, Rev. Mineral. Geochem., 52, 461–492, https://doi.org/10.2113/0520461, 2003.
Dengler, M. and Sommer, S.: Coupled benthic and pelagic oxygen, nutrient
and trace metal cycling, ventilation and carbon degradation in the oxygen
minimum zone of the Peruvian continental margin (SFB 754), Cruise No. M 136,
11.04.–03.05.2017 Callao (Peru)–Callao Solute-Flux Peru I,
METEOR-Berichte, https://doi.org/10.3289/CR_M136, 2017.
Dunne, J. P. and Murray, J. W.: Sensitivity of 234Th export to
physical processes in the central equatorial Pacific, Deep-Sea Res. Pt. I, 46, 831–854, https://doi.org/10.1016/S0967-0637(98)00098-3, 1999.
Echevin, V. M., Colas, F., Espinoza-Morriberon, D., Anculle, T., Vasquez,
L., and Gutierrez, D.: Forcings and evolution of the 2017 coastal El
Niño off Northern Peru and Ecuador, Front. Mar. Sci., 5, 367,
https://doi.org/10.3389/fmars.2018.00367, 2018.
Fischer, J., Brandt, P., Dengler, M., Müller, M., and Symonds, D.:
Surveying the upper ocean with the Ocean Surveyor: a new phased array
Doppler current profiler, J. Atmos. Ocean. Tech., 20,
742–751, https://doi.org/10.1175/1520-0426(2003)20<742:STUOWT>2.0.CO;2, 2003.
Garreaud, R. D.: A plausible atmospheric trigger for the 2017 coastal El
Niño, Int. J. Climatol., 38, e1296–e1302, https://doi.org/10.1002/joc.5426, 2018.
Gregg, M., D'Asaro, E., Riley, J., and Kunze, E.: Mixing efficiency in the
ocean, Annu. Rev. Mar. Sci., 10, 443–473, https://doi.org/10.1146/annurev-marine-121916-063643, 2018.
Gustafsson, Ö., Buesseler, K. O., Rockwell Geyer, W., Bradley Moran, S.,
and Gschwend, P. M.: An assessment of the relative importance of horizontal
and vertical transport of particle-reactive chemicals in the coastal ocean,
Cont. Shelf. Res., 18, 805–829, https://doi.org/10.1016/S0278-4343(98)00015-6, 1998.
Hahn, J., Brandt, P., Greatbatch, R. J., Krahmann, G., and Körtzinger,
A.: Oxygen variance and meridional oxygen supply in the Tropical North East
Atlantic oxygen minimum zone, Clim. Dynam., 43, 2999–3024, https://doi.org/10.1007/s00382-014-2065-0, 2014.
Henson, S. A., Sanders, R., Madsen, E., Morris, P. J., Le Moigne, F., and
Quartly, G. D.: A reduced estimate of the strength of the ocean's biological
carbon pump, Geophys. Res. Lett., 38, L04606, https://doi.org/10.1029/2011gl046735,
2011.
Kadko, D.: Upwelling and primary production during the US GEOTRACES East
Pacific Zonal Transect, Global Biogeochem. Cy., 31, 218–232,
https://doi.org/10.1002/2016GB005554, 2017.
Kaufman, A., Li, Y.-H., and Turekian, K. K.: The removal rates of 234Th
and 228Th from waters of the New York Bight, Earth Planet. Sc. Lett., 54, 385–392, https://doi.org/10.1016/0012-821X(81)90054-6, 1981.
Keeling, R. F. and Garcia, H. E.: The change in oceanic O2 inventory
associated with recent global warming, P. Natl. Acad. Sci. USA, 99, 7848–7853, https://doi.org/10.1073/pnas.122154899, 2002.
Kim, G., Hussain, N., and Church, T. M.: How accurate are the 234Th
based particulate residence times in the ocean?, Geophys. Res. Lett., 26, 619–622, https://doi.org/10.1029/1999GL900037,
1999.
Ku, T.-L., Knauss, K. G., and Mathieu, G. G.: Uranium in open ocean:
concentration and isotopic composition, Deep-Sea Res., 24, 1005–1017,
https://doi.org/10.1016/0146-6291(77)90571-9, 1977.
Law, C., Martin, A., Liddicoat, M., Watson, A., Richards, K., and Woodward,
E.: A Lagrangian SF6 tracer study of an anticyclonic eddy in the North
Atlantic: Patch evolution, vertical mixing and nutrient supply to the mixed
layer, Deep-Sea Res. Pt. II, 48,
705–724, https://doi.org/10.1016/S0967-0645(00)00112-0, 2001.
Le Moigne, F. A. C., Henson, S. A., Sanders, R. J., and Madsen, E.: Global
database of surface ocean particulate organic carbon export fluxes diagnosed
from the 234Th technique, Earth Syst. Sci. Data, 5, 295–304, https://doi.org/10.5194/essd-5-295-2013, 2013.
Lee, C., Murray, D., Barber, R., Buesseler, K., Dymond, J., Hedges, J.,
Honjo, S., Manganini, S., Marra, J., and Moser, C.: Particulate organic
carbon fluxes: compilation of results from the 1995 US JGOFS Arabian Sea
process study: By the Arabian Sea carbon flux group, Deep-Sea Res. Pt. II, 45, 2489–2501, https://doi.org/10.1016/S0967-0645(98)00079-4, 1998.
Lüdke, J., Dengler, M., Sommer, S., Clemens, D., Thomsen, S., Krahmann,
G., Dale, A. W., Achterberg, E. P., and Visbeck, M.: Influence of
intraseasonal eastern boundary circulation variability on hydrography and
biogeochemistry off Peru, Ocean Sci. Discuss., 2019, 1–31, https://doi.org/10.5194/os-2019-93, in review 2020.
McDougall, T., Feistel, R., Millero, F., Jackett, D., Wright, D., King, B.,
Marion, G., Chen, C., Spitzer, P., and Seitz, S.: The International
Thermodynamic Equation Of Seawater 2010 (TEOS-10): Calculation and Use of
Thermodynamic Properties, Global Ship-based Repeat Hydrography Manual, IOCCP
Report No. 14, 2009.
McKee, B. A., DeMaster, D. J., and Nittrouer, C. A.: Uranium geochemistry on
the Amazon shelf: Evidence for uranium release from bottom sediments,
Geochim. Cosmochim. Ac., 51, 2779–2786, https://doi.org/10.1016/0016-7037(87)90157-8, 1987.
Morris, P. J., Sanders, R., Turnewitsch, R., and Thomalla, S.:
234Th-derived particulate organic carbon export from an island-induced
phytoplankton bloom in the Southern Ocean, Deep-Sea Res. Pt. II, 54, 2208–2232, https://doi.org/10.1016/j.dsr2.2007.06.002, 2007.
Murray, J. W., Downs, J. N., Strom, S., Wei, C.-L., and Jannasch, H. W.:
Nutrient assimilation, export production and 234Th scavenging in the
eastern equatorial Pacific, Deep.-Sea Res., 36, 1471–1489, https://doi.org/10.1016/0198-0149(89)90052-6, 1989.
Nameroff, T., Balistrieri, L., and Murray, J.: Suboxic trace metal
geochemistry in the eastern tropical North Pacific, Geochim. Cosmochim. Ac., 66, 1139–1158, https://doi.org/10.1016/S0016-7037(01)00843-2, 2002.
Noffke, A., Hensen, C., Sommer, S., Scholz, F., Bohlen, L., Mosch, T.,
Graco, M., and Wallmann, K.: Benthic iron and phosphorus fluxes across the
Peruvian oxygen minimum zone, Limnol. Oceanogr., 57, 851–867,
https://doi.org/10.4319/lo.2012.57.3.0851, 2012.
Osborn, T.: Estimates of the local rate of vertical diffusion from
dissipation measurements, J. Phys. Oceanogr., 10, 83–89,
https://doi.org/10.1175/1520-0485(1980)010<0083:EOTLRO>2.0.CO;2, 1980.
Owens, S., Buesseler, K., and Sims, K.: Re-evaluating the 238U-salinity
relationship in seawater: Implications for the 238U–234Th
disequilibrium method, Mar. Chem., 127, 31–39, https://doi.org/10.1016/j.marchem.2011.07.005, 2011.
Owens, S. A., Pike, S., and Buesseler, K. O.: Thorium-234 as a tracer of
particle dynamics and upper ocean export in the Atlantic Ocean, Deep-Sea Res. Pt. II, 116, 42–59, https://doi.org/10.1016/j.dsr2.2014.11.010, 2015.
Peng, Q., Xie, S.-P., Wang, D., Zheng, X.-T., and Zhang, H.: Coupled
ocean-atmosphere dynamics of the 2017 extreme coastal El Niño, Nat. Commun., 10, 298, https://doi.org/10.1038/s41467-018-08258-8, 2019.
Pike, S., Buesseler, K., Andrews, J., and Savoye, N.: Quantification of
234Th recovery in small volume sea water samples by inductively coupled
plasma-mass spectrometry, J. Radioanal. Nucl. Ch.,
263, 355–360, https://doi.org/10.1007/s10967-005-0594-z, 2005.
Puigcorbé, V., Masqué, P., and Le Moigne, F. A. C.: Global database
of ratios of particulate organic carbon to thorium-234 in the ocean:
improving estimates of the biological carbon pump, Earth Syst. Sci. Data,
12, 1267–1285, https://doi.org/10.5194/essd-12-1267-2020, 2020.
Rapp, I., Schlosser, C., Menzel Barraqueta, J.-L., Wenzel, B., Lüdke, J., Scholten, J., Gasser, B., Reichert, P., Gledhill, M., Dengler, M., and Achterberg, E. P.: Controls on redox-sensitive trace metals in the Mauritanian oxygen minimum zone, Biogeosciences, 16, 4157–4182, https://doi.org/10.5194/bg-16-4157-2019, 2019.
Rengarajan, R., Sarin, M., and Krishnaswami, S.: Uranium in the Arabian Sea:
role of denitrification in controlling its distribution, Oceanol. Acta.,
26, 687–693, https://doi.org/10.1016/j.oceact.2003.05.001,
2003.
Resplandy, L., Martin, A. P., Le Moigne, F., Martin, P., Aquilina, A.,
Mémery, L., Lévy, M., and Sanders, R.: How does dynamical spatial
variability impact 234Th-derived estimates of organic export?, Deep-Sea Res. Pt. I, 68, 24–45, https://doi.org/10.1016/j.dsr.2012.05.015, 2012.
Roquet, F., Madec, G., McDougall, T. J., and Barker, P. M.: Accurate
polynomial expressions for the density and specific volume of seawater using
the TEOS-10 standard, Ocean Model., 90, 29–43, https://doi.org/10.1016/j.ocemod.2015.04.002, 2015.
Rosengard, S. Z., Lam, P. J., Balch, W. M., Auro, M. E., Pike, S., Drapeau, D., and Bowler, B.: Carbon export and transfer to depth across the Southern Ocean Great Calcite Belt, Biogeosciences, 12, 3953–3971, https://doi.org/10.5194/bg-12-3953-2015, 2015.
Santschi, P., Murray, J. W., Baskaran, M., Benitez-Nelson, C. R., Guo, L.,
Hung, C.-C., Lamborg, C., Moran, S., Passow, U., and Roy-Barman, M.: Thorium
speciation in seawater, Mar. Chem., 100, 250–268, https://doi.org/10.1016/j.marchem.2005.10.024, 2006.
Savoye, N., Benitez-Nelson, C., Burd, A. B., Cochran, J. K., Charette, M.,
Buesseler, K. O., Jackson, G. A., Roy-Barman, M., Schmidt, S., and Elskens,
M.: 234Th sorption and export models in the water column: a review,
Mar. Chem., 100, 234–249, https://doi.org/10.1016/j.marchem.2005.10.014, 2006.
Schafstall, J., Dengler, M., Brandt, P., and Bange, H.: Tidal-induced
mixing and diapycnal nutrient fluxes in the Mauritanian upwelling region,
J. Geophys. Res.-Oceans, 115, https://doi.org/10.1029/2009jc005940, 2010.
Schmidt, S. and Reyss, J.: Uranium concentrations of Mediterranean seawater
with high salinities, Comptes Rendus de l'Academie des Sciences. Serie 2,
312, 479–484, 1991.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic
oxygen content during the past five decades, Nature, 542, 335, https://doi.org/10.1038/nature21399, 2017.
Scholz, F., Hensen, C., Noffke, A., Rohde, A., Liebetrau, V., and Wallmann,
K.: Early diagenesis of redox-sensitive trace metals in the Peru upwelling
area–response to ENSO-related oxygen fluctuations in the water column,
Geochim. Cosmochim. Ac., 75, 7257–7276, https://doi.org/10.1016/j.gca.2011.08.007, 2011.
Scholz, F., McManus, J., Mix, A. C., Hensen, C., and Schneider, R. R.: The
impact of ocean deoxygenation on iron release from continental margin
sediments, Nat. Geosci., 7, 433–437, https://doi.org/10.1038/ngeo2162, 2014.
Shepherd, J. G., Brewer, P. G., Oschlies, A., and Watson, A. J.: Ocean
ventilation and deoxygenation in a warming world: introduction and overview,
Philos. T. R. Soc. A, 375, 20170240, https://doi.org/10.1098/rsta.2017.0240, 2017.
Smith, S. D.: Coefficients for sea surface wind stress, heat flux, and wind
profiles as a function of wind speed and temperature, J. Geophys. Res.-Oceans, 93, 15467–15472, https://doi.org/10.1029/JC093iC12p15467, 1988.
Steinfeldt, R., Sültenfuß, J., Dengler, M., Fischer, T., and Rhein, M.: Coastal upwelling off Peru and Mauritania inferred from helium isotope disequilibrium, Biogeosciences, 12, 7519–7533, https://doi.org/10.5194/bg-12-7519-2015, 2015.
Stramma, L., Johnson, G. C., Sprintall, J., and Mohrholz, V.: Expanding
oxygen-minimum zones in the tropical oceans, Science, 320, 655–658, https://doi.org/10.1126/science.1153847, 2008.
Suess, E., Kulm, L., and Killingley, J.: Coastal upwelling and a history of
organic-rich mudstone deposition off Peru, Geological Society, London,
Special Publications, 26, 181–197, https://doi.org/10.1144/GSL.SP.1987.026.01.11, 1987.
Swarzenski, P., Campbell, P., Porcelli, D., and McKee, B.: The estuarine
chemistry and isotope systematics of 234,238U in the Amazon and Fly
Rivers, Cont. Shelf. Res., 24, 2357–2372, https://doi.org/10.1016/j.csr.2004.07.025, 2004.
Thomsen, S. and Lüdke, J.: Microstructure measurements during METEOR cruise M136, PANGAEA, https://doi.org/10.1594/PANGAEA.890121, 2018.
Thomsen, S., Kanzow, T., Krahmann, G., Greatbatch, R. J., Dengler, M., and
Lavik, G.: The formation of a subsurface anticyclonic eddy in the
Peru-Chile Undercurrent and its impact on the near-coastal salinity,
oxygen, and nutrient distributions, J. Geophys. Res.-Oceans,
121, 476–501, https://doi.org/10.1002/2015JC010878, 2016.
Van Der Loeff, M. R., Sarin, M. M., Baskaran, M., Benitez-Nelson, C.,
Buesseler, K. O., Charette, M., Dai, M., Gustafsson, Ö., Masque, P., and
Morris, P. J.: A review of present techniques and methodological advances in
analyzing 234Th in aquatic systems, Mar. Chem., 100, 190–212,
https://doi.org/10.1016/j.marchem.2005.10.012, 2006.
Waples, J. T., Benitez-Nelson, C., Savoye, N., van der Loeff, M. R.,
Baskaran, M., and Gustafsson, Ö.: An introduction to the application and
future use of 234Th in aquatic systems, Mar. Chem., 100, 166–189,
https://doi.org/10.1016/j.marchem.2005.10.011, 2006.
Weinstein, S. E. and Moran, S. B.: Vertical flux of particulate Al, Fe, Pb,
and Ba from the upper ocean estimated from 234Th ∕238U
disequilibria, Deep-Sea Res. Pt. I, 52,
1477–1488, https://doi.org/10.1016/j.dsr.2005.03.008, 2005.
Xie, R. C., Le Moigne, F. A. C., Rapp, I., Lüdke, J., Gasser, B.,
Degnler, M., Liebetrau, V., and Achterberg, E. P.: Activities of total 234Th
and dissolved 238U during cruises M136 and M138 from the Peruvian Oxygen
Minimum Zone, PANGAEA, https://doi.org/10.1594/PANGAEA.921917,
2020.
Zhurbas, V. and Oh, I. S.: Drifter-derived maps of lateral diffusivity in
the Pacific and Atlantic oceans in relation to surface circulation patterns,
J. Geophys. Res.-Oceans, 109, C05015, https://doi.org/10.1029/2003JC002241, 2004.
Zimmerman, J. T. F.: Mixing and flushing of tidal embayments in the western
Dutch Wadden Sea part I: Distribution of salinity and calculation of mixing
time scales, Neth. J. Sea Res., 10, 149–191, https://doi.org/10.1016/0077-7579(76)90013-2, 1976.
Short summary
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.
Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But...
Altmetrics
Final-revised paper
Preprint