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