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SeaO2 - Past changes in Southern Ocean overturning circulation - implications for the partitioning of carbon and oxygen between the ocean and the atmosphere

English title SeaO2 - Past changes in Southern Ocean overturning circulation - implications for the partitioning of carbon and oxygen between the ocean and the atmosphere
Applicant Jaccard Samuel
Number 172915
Funding scheme SNSF Professorships
Research institution Institut für Geologie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Geochemistry
Start/End 01.10.2017 - 31.10.2019
Approved amount 759'179.00
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Keywords (7)

carbon cycle; biogeochemistry; chromium isotopes; greenhouse gases; ocean circulation; export production; Southern Ocean

Lay Summary (French)

Lead
Le concept général de ce projet de recherche est d’investiguer les processus biogéochimiques qui contrôlent les variations de productivité biologique marine. Les échanges de CO2 entre l’atmosphère et l’océan, modulés par les écosystèmes marins, jouent un rôle crucial dans l’évolution du cycle du carbone à l’échelle globale, et par conséquent dans les variations climatique de notre planète.
Lay summary

L’objectif principal de ce projet de recherche se focalise sur le développement d’un nouvel outil permettant de quantifier la variabilité de la pompe biologique marine à l’aide des isotopes stables du chrome (Cr). Malgré son importance dans le cycle du carbone, la productivité marine - et en particulier son rôle dans la séquestration du carbone dans les abysses de l’océan - reste étonnamment mal documentée. Ce projet propose d’explorer un nouveau traceur, récemment développé pour mieux comprendre la lente oxygénation de l’atmosphère primitive de la Terre, et de le développer à l’aide d’un programme de calibration multidisciplinaire permettant son application aux variations des conditions redox plus réduites associées à la reminéralisation de la matière organique en milieu marin. Ce projet propose d’exploiter les échantillons récoltés durant l’expédition océanographique ACE (Antarctic Circumnavigation Expedition) et combine des expériences d’incubation de phytoplancton ainsi que des investigations de la colonne d’eau dans le but de caractériser les mécanismes gouvernant la réduction du Cr et le fractionnement isotopique concomitant associé avec la production et la reminéralisation de la matière organique. Ces observations permettront de mieux comprendre l’évolution du cycle du carbone dans la perspective d’une lente, mais inexorable saturation de la capacité d’absorption du CO2 d’origine anthropique par l’océan à l’échelle globale.

Direct link to Lay Summary Last update: 13.08.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
A Mg(OH) 2 coprecipitation method for determining chromium speciation and isotopic composition in seawater
Davidson Ashley B., Semeniuk David M., Koh Jasmine, Holmden Chris, Jaccard Samuel L., Francois Roger, Crowe Sean A. (2020), A Mg(OH) 2 coprecipitation method for determining chromium speciation and isotopic composition in seawater, in Limnology and Oceanography: Methods, 18(1), 8-19.
Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean
Janssen David J., Rickli Jörg, Quay Paul D., White Angelicque E., Nasemann Philipp, Jaccard Samuel L. (2020), Biological Control of Chromium Redox and Stable Isotope Composition in the Surface Ocean, in Global Biogeochemical Cycles, 34(1), e2019GB006.
Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years
Pöppelmeier F., Gutjahr M., Blaser P., Oppo D.W., Jaccard S.L., Regelous M., Huang K.-F., Süfke F., Lippold J. (2019), Water mass gradients of the mid-depth Southwest Atlantic during the past 25,000 years, in Earth and Planetary Science Letters, 531, 115963-115963.
Mechanisms of millennial-scale atmospheric CO2 change in numerical model simulations
Gottschalk Julia, Battaglia Gianna, Fischer Hubertus, Frölicher Thomas L., Jaccard Samuel L., Jeltsch-Thömmes Aurich, Joos Fortunat, Köhler Peter, Meissner Katrin J., Menviel Laurie, Nehrbass-Ahles Christoph, Schmitt Jochen, Schmittner Andreas, Skinner Luke C., Stocker Thomas F. (2019), Mechanisms of millennial-scale atmospheric CO2 change in numerical model simulations, in Quaternary Science Reviews, 220, 30-74.
Low terrestrial carbon storage at the Last Glacial Maximum: constraints from multi-proxy data
Jeltsch-Thömmes Aurich, Battaglia Gianna, Cartapanis Olivier, Jaccard Samuel L., Joos Fortunat (2019), Low terrestrial carbon storage at the Last Glacial Maximum: constraints from multi-proxy data, in Climate of the Past, 15(2), 849-879.
The residence time of Southern Ocean surface waters and the 100,000-year ice age cycle
Hasenfratz Adam P., Jaccard Samuel L., Martínez-García Alfredo, Sigman Daniel M., Hodell David A., Vance Derek, Bernasconi Stefano M., Kleiven Helga (Kikki) F., Haumann F. Alexander, Haug Gerald H. (2019), The residence time of Southern Ocean surface waters and the 100,000-year ice age cycle, in Science, 363(6431), 1080-1084.
Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial
Duchamp-Alphonse Stéphanie, Siani Giuseppe, Michel Elisabeth, Beaufort Luc, Gally Yves, Jaccard Samuel L. (2018), Enhanced ocean-atmosphere carbon partitioning via the carbonate counter pump during the last deglacial, in Nature Communications, 9(1), 2396-2396.
Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle
Cartapanis Olivier, Galbraith Eric D., Bianchi Daniele, Jaccard Samuel L. (2018), Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle, in Climate of the Past, 14(11), 1819-1850.
Past Carbonate Preservation Events in the Deep Southeast Atlantic Ocean (Cape Basin) and Their Implications for Atlantic Overturning Dynamics and Marine Carbon Cycling
Gottschalk Julia, Hodell David A., Skinner Luke C., Crowhurst Simon J., Jaccard Samuel L., Charles Christopher (2018), Past Carbonate Preservation Events in the Deep Southeast Atlantic Ocean (Cape Basin) and Their Implications for Atlantic Overturning Dynamics and Marine Carbon Cycling, in Paleoceanography and Paleoclimatology.

Associated projects

Number Title Start Funding scheme
144811 SeaO2 - Past changes in Southern Ocean overturning circulation - implications for the partitioning of carbon and oxygen between the ocean and the atmosphere 01.10.2013 SNSF Professorships

Abstract

The overarching objective of this research proposal is to further develop a novel tool to trace changes in the strength of the marine biological pump based on stable chromium (Cr) isotopes. Despite its significance for the global carbon cycle, marine export productivity is still poorly constrained. This proposal will explore an emerging tracer that has recently been developed to investigate the rise of atmospheric oxygen in the early history of the Earth and develop it thoroughly through a comprehensive, multidisciplinary calibration program and apply it to the much more subtle redox variations associated with organic matter remineralization in the ocean, using the Southern Ocean as a natural laboratory. The proposed approach takes advantage of a scheduled sea-going expedition (Antarctic Circumnavigation Expedition (ACE), managed by the Swiss Polar Institute) and will combine phytoplankton incubation experiments, water-column investigations and aims at elucidating the mechanisms governing the reduction of Cr and its associated isotopic fractionation in the marine environment. The observations gathered within the framework of this research program will enable refining the evolution of the marine carbon cycle and the rapidly declining buffering capacity of the ocean.
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