Prof. François Fripiat

Laboratoire de Glaciologie
Department Geosciences, Environment and Society

Université Libre de Bruxelles
Av. F.D. Roosevelt, 50, CP160/03
1050 Brussels, Belgium

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Glaciology, Oceanography, Paleoclimatology

Isotope (bio)geochemistry, isotope tracers, Pleistocene Ice Age, Anthropocene,

Southern Ocean, Arctic Ocean, sea ice, Atmospheric Chemistry 

Research appointments

2019-present  - Assistant Professor, Université Libre de Bruxelles, Brussels, Belgium

2016-2019  - Research associate, Max-Planck Institute for Chemistry, Mainz, Germany

2013-2016  - Postdoctoral fellowship (FWO), Vrije Universiteit Brussel, Brussels, Belgium

2011-2013  - Postdoctoral research associate, Princeton University, Princeton, USA

2010-2013  - Postdoctoral fellowship (FNRS), Université Libre de Bruxelles, Brussels, Belgium

2006-2010 - Research assistant, Royal Museum for Central Africa, Tervuren, Belgium

Education

Université Libre de Bruxelles, Brussels, Belgium

2010 - Ph.D. Geosciences

2005 - M.A. Geosciences

 

Teaching 

 

2019-Present - Assistant professor at Université Libre de Bruxelles for the Bachelor in Geography, Masters in Environmental Sciences and Management, Geology, Chemistry and Bioengineering: Earth’s system interactions; Paleoclimatology; Matter and Energy in the Environment: Analysis, transport and instability; In-depths questions in glaciology-atmosphere-climate; Master thesis learning; Stage; field excursion in geography

2015-2020 - Visiting professor at ULiège for the Master in Oceanography: Dynamic of nutrients in marine environment, part I: Chemical and biogeochemical aspects

2013-2014 - Teaching assistant at VUB for the Master in Chemistry (Prof. P. Claeys): Environmental Chemistry

2010-2011 - Teaching assistant at ULB for the Master in Environmental Sciences and Management and the Master in Geology (Prof. L. André): Isotope geochemistry applied to the environment

Co-directed Ph.D. and Ms. Thesis

2021-2025Promotor of the Ph.D. thesis of Lisa Ardoin (ULB) “Retrieval of the oldest paleoclimatic signal in basal ice, insights from a large-scale multi-parametric study”

2020-2024 - Promotor of the Ph.D. thesis of Sofia Muller (ULB-ULiège) “Sources and sinks of nitrous oxide in the Arctic Ocean”

2018-2022 - Co-promotor of the Ph.D. thesis of Sarah Wauthy (ULB) “Ice core evidence of surface mass balance and sea ice extent changes across the Anthropocene transition in East Antarctica”

2016-2020 - Co-promotor of the Ph.D. thesis of Caroline Jacques (ULB-ULiège) “Using isotopes to understand the role of sea ice in the biogeochemical cycle of methane”.

2016-2020 - Co-promotor of the Ph.D. thesis of Florian Deman (VUB-ULiège) “Nitrous oxide and nitrogen cycling in Antarctic sea ice covered zone”

2013-2018 - Co-promotor of the Ph.D. thesis of Arnout Roukaerts (VUB) “Novel insights in nitrogen and carbon biogeochemistry of Antarctic sea ice: the potential role of a microbial biofilm”

2013-2020 - Reader and mentor of several Ms. Thesis at ULB (‘Geosciences, Environment & Society’ and ‘Ecole interfacultaire de Bioingénieurs’), VUB (‘Ocean & Lakes’), ULiège (‘Astrophysics, Geophysics and  Oceanography’) and UCLouvain (‘Faculté des Bioingénieurs’)

Services

2021-Present  - Associate member of the SCOR working group CIce2Clouds: Coupling ocean-ice-atmosphere processes from sea-ice biogeochemistry to aerosols and clouds. 

2020-Present - Chair of the basal ice consortium for the Beyond-Epica project (H2020 Research and Innovation programme). https://www.beyondepica.eu/en/

2020-Present - Steering committee of IPICS (International Partnerships in Ice Core Sciences; PAGES, SCAR, and IACS-supported). http://pastglobalchanges.org/science/end-aff/ipics/intro

2020-Present -Member of the SCOR (Scientific Committee for Oceanic Research) national committee-Belgium (SCOR-BE).

2017-Present - Co-chair of the SCOR (Scientific Committee for Oceanographic Research) working group ECV-ice: Measuring Essential Climate Variables in sea ice. https://sites.google.com/view/ecv-ice/ 

2016-Present - Steering committee of the research community BEPSII (SOLAS and CLIC).  https://sites.google.com/site/bepsiiwg140/home

2015-Present - Associate member of the Belgian National Committee on Antarctic Research. 

2013-2016 - Associated member of the SCOR (Scientific Committee for Oceanic Research) working group BEPSII: Bieogeochemical Exchanges Process at the Sea-Ice Interfaces.

2007-Present - Participation to projects related to the IPY, GOSHIP and GEOTRACES .

Fundings

2022-2023 - Coordinator of the GENIAL project (FWB) "Gas concentrations and isotopes in the deepest part of the Antarctic and Greenland ice sheets: Environmental and paleoclimatic implications"

2022-2023 - Coordinator of the AEROBIC project (FNRS) "Gas concentrations and isotopes in basal ice"

2022-2025 - Coordinator of the QUOI project (FWB): The quest for the world's oldest ice. 

2021-2023 - Coordinator of the ISOGLACIO project (FWB): Reactive nitrogen isotopes in glaciology, from microbes to atmospheric chemistry. 

2021-2025 - Beneficiary of an Innovative Training Network DEEPICE (H2020-MSCA-ITN-2020; link) Research and Training on understanding deep ice core proxies to infer past Antarctic climate dynamics. 

2021-2022 - Coordinator of a project dedicated to Antarctic Ice Sheet and sea-ice extent during the Anthropocene (Fonds Emile Defay). 

2017-2020 - Co-Chair of the SCOR working group ECV-ice: Measuring  Essential Climate Variables in sea ice. Co-Chair with Prof. D. Nomura (Hokkaido University) and Prof. B.G.T. Else (University of Calgary)

2016-2019 - Principal Investigator of OCEANIC project (nitrous oxide and nitrogen Cycling in Antarctic sea ice Covered zone), funded by BELSPO (Belgian Science Policy)

2013-2016 - FWO postdoctoral fellowship (PI) (Re-assessing the significance of nutrient cycling by the marine pelagic and sympagic microbial community based on nitrogen and silicon isotope dynamics), Vrije Universiteit Brussel

2010-2014 - Principal investigator of BIGSOUTH project (BioGeochemical cycles in the SOUTHern Ocean: Role within the Earth System), funded by BELSPO (Belgian Science Policy) 

2010-2013 - FNRS postdoctoral fellowship (PI) (Nitrogen and silicon isotopic signatures in the sea ice and surface waters of the polar ocean), Université Libre de Bruxelles

2010 - COST short-term scientific mission (PI) “Nitrogen and Silicon isotopic signatures in Arctic sea ice (Greenland coastal area)”, in collaboration with Dirk Notz from the Max Planck Institute for Meteorology (Hamburg, Germany)

Publications

Book Chapters

1- Sigman, D.M., and Fripiat, F., 2019. Nitrogen isotopes in the Ocean. In Cochran J. Kirk, Bokuniewicz J. Henry, Yager L. Patricia (eds). Encyclopedia of Ocean Sciences, 3rd Edition, pp. 263-278. Oxford: Elsevier, doi:10.1016/B978-0-12-409548-9.11605-7.

Publication in peer-reviewed journals 

Published

47- Campbell, K., I. Matero, C. Bellas, T. Turpin-Jelfs, P. Anhaus, M. Graeve, F. Fripiat, M. Tranter, J.C. Landy, P. Sanchez-Baracaldo, E. Leu, C. Katlein, C.J. Mundy, S. Rysgaard, L. Tedesco, C. Haas, and M. Nicolaus, 2021. Monitoring a changing Arctic: Recent advancements in the study of sea ice microbial communities. Ambio 51, 318-332.

 

46- Fripiat, F., A. Martinez-Garcia, D. Marconi, S.E. Fawcett, S.H. Kopf, V.H. Luu, P.A. Rafter, R. Zhang, D.M. Sigman, and G.H. Haug, 2021. Nitrogen isotopic constraints on nutrient sources to the upper ocean.  Nature Geoscience. doi:10.1038/s41561-021-00836-8

45- Jacques, C., C.J. Sapart, F. Fripiat, G. Carnat, J. Zhou, B. Delille, T. Röckmann, C. Van der Veen, H. Nieman, and J.-L. Tison, 2021. Sources and sinks of methane in sea ice: insights from stable isotopes. Elementa: Science of the Anthropocene 9(1), 00167. doi:10.1525/elementa.2020.00167

44- Farmer, J.R., D.M. Sigman, J. Granger, O.M. Underwood, F. Fripiat, T.M. Cronin, A. Martinez-Garcia, and G.H. Haug, 2021. Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age. Nature Geoscience. doi:10.1038/s41561-021-00789-y

43-Roukaerts, A., F. Deman, F. Van der Linden, G. Carnat, A. Bratkic, S. Moreau, D. Lannuzel, F. Dehairs, B. Delille, J.-L. Tison, and F. Fripiat, 2021. The biogeochemical role of a microbial biofilm in sea ice: Antarctic landfast sea ice as a case study. Elementa: Science of the Anthropocene 9(1):00134. doi:10.10525/elementa.2020.00134

42- Deman, F., D. Fonseca-Batista, A. Roukaerts, M.I. Garcia-Ibanez, E. Le Roy, E.P.D.N. Thilakarathne, M. Elskens, F. Dehairs, and F. Fripiat, 2021. Nitrate supply routes and impact of internal cycling in the North Atlantic Ocean inferred from nitrate isotopic composition. Global Biogeochemical Cycles 35, doi:10.1029/2020GB006887

41-Sigman, D.M., F. Fripiat, A.S. Studer, P.C. Kemeny, A. Martinez-Garcia, M.P. Hain, X. Ai, X. Wang, H. Ren, and G.H. Haug, 2021. The Southern Ocean during the ice ages: A review of the Antarctic isolation hypothesis, with comparison to the North Pacific. Quaternary Science Reviews 254, 106732, doi:10.1016/j.quascirev.2020.106732

 

40- Ai, X.E., A. Studer, D.M. Sigman, A. Martinez-Garcia, F. Fripiat, L.M. Thöle, E. Michel, J. Gottschalk, L. Arnold, S. Moretti, M. Schmitt, S. Oleynik, S.L. Jaccard, and G.H. Haug, 2020. Southern Ocean upwelling, Earth's obliquity, and glacial-interglacial atmospheric CO2 change. Science 370, 1348-1352, https://doi.org/10.1126/science.abd2115

39- Lannuzel, D., et al. (F. Fripiat), 2020. The future of Arctic sea-ice biogeochemistry and ice-associated ecosystems. Nature Climate Changehttps://doi.org/10.1038/s41558-020-00940-4   

38- Miller, L., F. Fripiat, S. Moreau, D. Nomura, J. Stefels, N. Steiner, L. Tedesco, and M. Vancoppenolle, 2020. Implications of sea ice management for Arctic biogeochemistry. Eos, 101, https://doi.org/10.1029/2020EO149927

 

37- Hainbucher, D., et al. (F. Fripiat), 2020. Variability and trends in physical and biogeochemical parameters of the Mediterranean Sea during a cruise with RV Maria S. Merian in March 2018. Earth System Science Data, doi:10.5194/essd-2020-82.

36- Tison, J.-L., et al. (F. Fripiat), 2020. Physical and biological properties of Early Winter Antarctic Sea Ice in the Ross Sea. Annals of Glaciology, 1-19, doi.10.1017/aog.2020.43.

35-Van der Linden, F., et al., (F.Fripiat), 2020. Sea ice CO2 dynamics across seasons: impact of processes at the interfaces. Journal of Geophysical ResearchOceans, 125(6), doi:10.1029/2019JC015807. 

34- Nomura, D., P. Wongpan, T. Toyota, T. Tanikawa, Y. Kawaguchi, T. Ono, T. Ishino, M. Tozawa, T.P. Tamura, I.S. Yabe, E.Y. Son, F. Vivier, A. Lourenco, M. Lebrun, Y. Nosaka, T. Hirawake, A. Ooki, S. Aoki, B. Else, F. Fripiat, J. Inoue, and M. Vancoppenolle, 2020. Saroma-Ko Lagoon observations for sea ice physico-chemistry and ecosystems 2020 (SLOPE2019). Bulletin of Glaciological Research, Japanese Society of Snow and Ice 38, 1-12.

33- Closset, I., D. Cardinal, T.W. Trull, and F. Fripiat (2019). Silicon isotope model enhances our understanding of  processes controlling the δ30Si of settling diatoms and our interpretation of paleo-records. Global Biogeochemical Cycles 33, doi://doi.org/10.1029/2018GB006115.

32- Roukaerts, A., D. Nomura, H. Hattori, F. Deman, F. Dehairs, and F. Fripiat (2019). Melting treatments have no effect on the assessment of biomass and nutrients in sea ice (Saroma-Ko lagoon, Hokkaido, Japan). Polar Biology 42(2): 347-356.

31- Fripiat, F., Martinez-Garcia, A., S.E. Fawcett, A.S. Studer, S.M. Smart, F. Rubach, P.C. Kemeny, S. Oleynik, D.M. Sigman and G.H. Haug (2019). The isotope effect of nitrate assimilation in the Antarctic Zone: Improved estimates and paleoceanographic implications. Geochimica et Cosmochimica Acta 247: 261-279.

30- Fonseca-Batista, D., Li, X., Riou, V., Michotey, V., Deman, F., Fripiat, F., Guasco, S., Brion, N., Lemaitre, N. Tonnard, M., Gallinari, M., Planquette, H., Planchon, F.., Sarthou, V., Elskens, M., Chou, L., and Dehairs F. (2019). Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic. Biogeosciences 16, 999-1017.

29- Kemeny, P.C., Kast E.R., Hain M.P., Fawcett S.E., Fripiat F., Studer A.S., Martinez-Garcia A., Haug G.H., and Sigman D.M. (2018). A seasonal model of nitrogen isotope in the ice age Antarctic Zone: Support for reduced upper cell overturning. Paleoceanography and Paleoclimatology 33: 1453-1471.

28- Carnat, G., Said-Ahmad W., Fripiat F., Wittek B., J.-L. Tison, and A. Amrani (2018). Large sulfur isotope variability suggests unique DMSP cycling and metabolism in Antarctic sea ice. Nature Communications Biology 1:212, doi:10.1038/s42003-018-0228-y.  

 

27- Meiners, K.M., M. Vancoppenolle, et al. (F. Fripiat) (2018). Chlorophyll-a in Antarctic land-fast sea ice: a synthesis of historical ice-core data. Journal of Geophysical Research 123: 8444-8453.

 

26- Fripiat, F., M. Declercq, C.J. Sapart, L.G. Anderson, V. Bruechert, F. Deman, D. Fonseca-Batista, C. Humborg, A. Roukaerts, I.P. Semiletov, and F. Dehairs (2018). Influence of the bordering shelves on nutrient distribution in the Arctic halocline inferred from water column nitrate isotopes. Limnology and Oceanography 63: 2154-2170, doi:10.1002/lno.10930.

 

25- Schlitzer, R. et al., (Fripiat F.) (2018). The GEOTRACES intermediate data product 2017. Chemical Geology 493: 210-223.

 

24- Benetti, M., E. Sveinbjörnsdottir, R. Olafsdottir, M.J. Leng, C. Arrowsmith, K. Debondt, F. Fripiat, and G. Aloisi (2017). Inter-comparison of salt effect correction for δ18O and δD measurements in seawater by IRMS and CRDS. Marine Chemistry 194: 114-123.

 

23- Fripiat, F., K.M. Meiners, M. Vancoppenolle, S. Papadimitriou, D.N. Thomas, S.F. Ackley, K.R. Arrigo, G. Carnat, S. Cozzi, B. Delille, G.S. Dieckmann, R.B. Dunbar, A. Fransson, G. Kattner, H. Kennedy, D. Lannuzel, D.R. Munro, D. Nomura, J.-M. Rintala, V. Schoemann, J. Stefels, N. Steiner, and J.-L. Tison (2017). Macro-nutrient concentrations in Antarctic pack ice: overall patterns and overlooked processes. Elementa: Science of the Anthropocene 5: 13, doi:http://doi.org/10.1524.elementa.217.

Science features in CLIC newsletters 

 

22- Fonseca-Batista, D., F. Dehairs, V. Riou, F. Fripiat, M. Elskens, F. Deman, N. Brion, F. Quéroué, M. Bode, and H. Auel (2017). Nitrogen fixation in the eastern Atlantic reaches similar levels in the Southern and Northern hemisphere. Journal of Geophysical Research 122, doi:10.1002/2016JC012335.

 

21- Roukaerts, A., A.-J. Cavagna, F. Fripiat, D. Lannuzel, K.M. Meiners, and F. Dehairs (2016). Sea-ice algal primary production and nitrogen uptakes off East Antarctica. Deep-Sea Research II 131, 140-159.

 

20- Mawji, E. et al., (Fripiat F.) (2015). The GEOTRACES intermediate data product 2014. Marine Chemistry 177, 1-8, doi:10.1016/j.marchem.2015.04.005

 

19- Fripiat, F., M. Elskens, T.W. Trull, S. Blain, A.-J. Cavagna, C. Fernandez, D. Fonseca-Batista, F. Planchon, A. Roukaert, and F. Dehairs (2015). Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean. Global Biogeochemical Cycles 29, 1929-1943, doi:10.1002/2014GB0050

 

18- Fripiat, F., D.M. Sigman, G. Massé, and J.-L. Tison (2015). High turnover rates indicated by changes in the fixed N forms and their stable isotopes in Antarctic landfast sea ice. Journal of Geophysical Research 120, doi:10.1002/2014JC010583.

 

17- Cavagna, A.-J., F. Fripiat, M. Elskens, F. Dehairs, P. Mangion, L. Chirurgien, I. Closset, M. Lasbleiz, L. Flores-Leiva, D. Cardinal, K. Leblanc, C. Fernandez, D. Lefèvre, L. Oriol, S. Blain, and B. Quéguiner (2015). Biological productivity regime and associated N cycling in the surface waters over and downstream the Kerguelen Island area, Southern Ocean. Biogeosciences 12, 6515-6528.

 

16- Miller, L.A., F. Fripiat, B.G.T. Else, J.S. Bowman, K.A. Brown, R.E. Collins, M. Ewert, A. Fransson, M. Gosselin, D. Lannuzel, K.M. Meiners, C. Michel, J. Nishioka, D. Nomura, S. Papadimitriou, L.M. Russel, L.L. Sorensen, D.N. Thomas, J.-L. Tison, M.A. van Leeuwe, M. Vancoppenolle, E.W. Wolff, and J. Zhou (2015). Methods for biogeochemical studies of sea ice: The state of the art, caveats, and recommendations. Elementa: Science of the Anthropocene 3:000038, doi:10.12952/journal.elementa.000038.

 

15- Dehairs, F., F. Fripiat, A.-J. Cavagna, T.W. Trull, C. Fernandez, D. Davies, A. Roukaerts, D. Fonseca-Batista, F. Planchon, M. Elskens (2015). Nitrogen cycling in the Southern Ocean Kerguelen Plateau area: evidence for significant surface nitrification from nitrate isotopic compositions. Biogeosciences 12, 1713-1731.

 

14- Carnat, G., J. Zhou, T. Papakyriakou, B. Delille, T. Goossens, T. Haskell, V. Schoemann, F. Fripiat, J.-M. Rintala and J.-L. Tison (2014). Physical and biological controls on DMS,P dynamics in ice-shelf influenced fast ice during a winter-spring and a spring-summer transitions. Journal of Geophysical Research 119, 2882-2905.

 

13- Fripiat, F., J.-L. Tison, L. André, D. Notz, and B. Delille (2014). Biogenic silica recycling in sea ice inferred from Si-isotopes: Constraints from Arctic winter first-year sea ice. Biogeochemistry 119, 25-33, doi:10.1007/s10533-013-9911-8.

 

12- Fripiat, F., D.M. Sigman, S.E. Fawcett, P.A. Rafter, M.A. Weigand, and J.-L. Tison (2014). New insights into sea ice nitrogen biogeochemical dynamics from nitrogen isotopes. Global Biogeochemical Cycles 28(2), 115-130, doi:10.1002/2013GB004729.

 

11- de Brauwere, A., F. Fripiat, D. Cardinal, A.-J. Cavagna, L. André, M. Elskens (2012). Isotopic model of oceanic silicon cycling: the Kerguelen Plateau case study. Deep Sea Research I. 70, 42-59.

10- Fripiat, F., A.J. Cavagna, F. Dehairs, A. de Brauwere, L. André, and D. Cardinal (2012). Processes controlling Si-isotopic composition in the Southern Ocean for an application in paleoceanography. Biogeosciences 9, 2443–2457

9- Fripiat, F., A.J. Cavagna, F. Dehairs, S. Speich, L. André, and D. Cardinal (2011). Silicic acid pools dynamics in the Antarctic Circumpolar Current inferred from Si-isotopes. Ocean sciences 8, 533-547.

8- Fripiat, F., K. Leblanc, A.-J. Cavagna, M. Elskens, L. Armand, L. André, F. Dehairs, and D. Cardinal (2011). Summer efficient silicon loop despite contrasted diatom Si-affinity across the Polar Front and SubAntarctic Zone. Marine Ecological Progress Series 435: 47-61.

 

7- Cavagna, A.-J., M. Elskens, F.B. Griffiths, F. Fripiat, S.H.M. Jacquet, K.J. Westwood, and F. Dehairs (2010). Contrasting regimes of production and potential for carbon export in the SAZ and PFZ south of Tasmania. Deep-Sea Research II. 58, 2235-2247.

 

6- Cavagna, A.-J., F. Fripiat, F. Dehairs, D. Wolf-Gladrow, B. Cisewski, N. Savoye, L. André, and D. Cardinal (2011). Silicon uptake and supply during a Southern Ocean iron fertilization experiment (EIFEX) tracked by Si-isotopes. Limnology & Oceanography 56(1): 147-160.

 

5- Fripiat, F., A.J. Cavagna, N. Savoye, F. Dehairs, L. André, and D. Cardinal (2011). Isotopic constraints on the Si-biogeochemical cycle of the Antarctic Zone. Marine Chemistry 123: 11-22.

 

4- Fripiat, F., R. Corvaisier, J. Navez, M. Elskens, V. Schoemann, K. Leblanc, L. André, and D. Cardinal (2009). Measurements of production-dissolution rates of marine biogenic silica by 30Si-isotope dilution using a high-resolution sector field ICP-MS. Limnology & Oceanography: Methods 7: 470-478.

 

3- Abraham, K., S. Opfergelt, F. Fripiat, A.-J. Cavagna, J.T.M. de Jong, S.F. Foley, L. André, and D. Cardinal (2008). δ29Si and δ30Si determination on USGS BHVO-1 and BHVO-2 reference materials with a new configuration on a Nu Plasma Multi-Collector ICP-MS. Geostandards and Geoanalytical Research 32 (2): 193-202.

 

2- Cardinal, D., N. Savoye, T.W. Trull, F. Dehairs, E. Kopcynska, F. Fripiat, J.-L. Tison, and L. André (2007). Silicon isotopes in spring Southern Ocean diatoms: large zonal changes despite homogeneity among size fractions.  Marine Chemistry 106: 46-62.

1- Fripiat, F., D. Cardinal, J.-L. Tison, A. Worby, and L. André (2007). Diatoms-induced Si-isotopic fractionation in Antarctic Sea-ice. Journal of Geophysical Research 112, G02001, doi: 10.1029/2006JC000244.

Research Interests

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Ocean dynamic and nitrate isotopes

Fig. Nitrate isotope database in the Ocean. Colorscale is for the depth of the 27.5 g kg-1 isopycnal (i.e., depth of the global pycnocline). Reprint from Fripiat et al. 2021, Nat. Geo. 

Model-based projects on large-scale observations of nitrate isotopes: oceanic circulation, ocean productivity, oceanic fixed N budget ...

- Fripiat, F., D.M. Sigman, A. Martinez-Garcia, D. Marconi, X.E. Ai, A. Auderset, S.E. Fawcett, S. Moretti, A.S. Studer, and G.H. Haug (2022). The impact of incomplete nutrient consumption in the Southern Ocean on global mean ocean nitrate δ15N. In revision in Global Biogeochemical Cycles

- Fripiat, F., A. Martinez-Garcia, D. Marconi, S.E. Fawcett, S.H. Kopf, V.H. Luu, P.A. Rafter, R. Zhang, D.M. Sigman, and G.H. Haug (2021). Nitrogen isotopic constraints on nutrient sources to the upper ocean. Nature Geoscience 14, 855-861, doi:10.1038/s41561-021-00836-8.

- Sigman, D.M., and Fripiat, F. (2019). Nitrogen isotopes in the Ocean. In Cochran J. Kirk, Bokuniewicz J. Henry, Yager L. Patricia (eds). Encyclopedia of Ocean Sciences, 3rd Edition, pp. 263-278. Oxford: Elsevier, doi:10.1016/B978-0-12-409548-9.11605-7.

Fig. Processes affecting the nitrogen isotopes in the ocean. Reprint from Sigman and Fripiat (2019) in Encyclopedia of Ocean Sciences

Southern Ocean overturning and atmospheric CO2 during ice ages

Proxy calibration, implications for paleoceanography. 

- Fripiat, F., Martinez-Garcia, A., S.E. Fawcett, A.S. Studer, S.M. Smart, F. Rubach, P.C. Kemeny, S. Oleynik, D.M. Sigman and G.H. Haug (2019). The isotope effect of nitrate assimilation in the Antarctic Zone: Improved estimates and paleoceanographic implications. Geochimica et Cosmochimica Acta 247, 261-279, doi:10.1016/j.gca.2018.12.003

 

- Fripiat, F., A.J. Cavagna, F. Dehairs, A. de Brauwere, L. André, and D. Cardinal (2012). Processes controlling Si-isotopic composition in the Southern Ocean for an application in paleoceanography. Biogeosciences 9, 2443–2457, doi:10.5194/bg-9-2443-2012

Fig. Meridional depth sections of nitrate concentration (a), potential temperature (b), nitrate+nitrite δ15N (c) and nitrate+nitrite δ18O (d) in the Indian Sector at 78-95°E (GOSHIP section IO8S). The thin white lines represent the contours for NO3- concentration (a), potential temperature (b),  nitrate+nitrite δ15N (c) and nitrate+nitrite δ18O (d). The isopycnal delimiting Upper and Lower Circumpolar Deep Water is represented by the thick black solid line. The sections were generated with Ocean Data View [Available at http://odv.awi.de]. Reprint from Fripiat et al., 2019, Geochim. Cosmochim. Acta. 

Nitrogen isotope composition of fossil-bound N recovered from Southern Ocean sediment cores to provide a measure of the degree of nitrate consumption in the high-latitude ocean. This proxy is used to formulate and test hypotheses on fluctuations in atmospheric CO2 and oceanic circulation over glacial cycles.

- Fripiat, F., D.M. Sigman, X.E. Ai, A.S. Studer, P.C. Kemeny, M.P. Hain, X. Wang, H. Ren, G.H. Haug, and A. Martinez-Garcia (2022). Southern Ocean biogeochemical consequences of reduced wind-driven upwelling during ice ages. Submitted in Paleoceanography and Paleoclimatology

 

- Sigman, D.M., F. Fripiat, A.S. Studer, P.C. Kemeny, A. Martinez-Garcia, M.P. Hain, X. Ai, X. Wang, H. Ren, and G.H. Haug, (2021). The Southern Ocean during the ice ages: A review of the Antarctic isolation hypothesis, with comparison to the North Pacific. Quaternary Science Reviews 254, 106732, doi:10.1016/j.quascirev.2020.106732

- Ai, X.E., A.S. Studer, D.M. Sigman, A. Martinez-Garcia, F. Fripiat, L.M. Tholle, E. Michel, J. Gottschalk, L. Arnold, S. Moretti, M. Schmitt, S. Oleynik, S.L. Jaccard and G.H. Haug, (2021). Southern Ocean upwelling, Earth's obliquity, and glacial-interglacial atmospheric CO2 change. Science 370, 1348-1352, doi:10.1126/science.abd2115

Kemeny, P.C., Kast E.R., Hain M.P., Fawcett S.E., Fripiat F., Studer A.S., Martinez-Garcia A., Haug G.H., and Sigman D.M. (2018). A seasonal model of nitrogen isotope in the ice age Antarctic Zone: Support for reduced upper cell overturning. Paleoceanography and Paleoclimatology 33, 1453-1471, doi:10.1029/2018PA003478

Fig. Schematic of the global ocean's interior circulation today (a) and a proposal for the last glacial maximum (b, LGM). Abbreviations are as follows: PAZ, Polar Antarctic Zone; OAZ, Open Antarctic Zone; SAZ, Subantarctic Zone; NADW, North Atlantic Deep Water, GNAIW, Glacial North Atlantic Intermediate Water; PDW, Pacific Deep Water; IDW, Indian Deep Water; UCDW, Upper Circumpolar Deep Water; LCDW, Lower Circumpolar Deep Water; AABW, Antarctic Bottom Water; AAIW, Antarctic Intermediate Water; SAMW, Subantarctic Mode Water; ITF, Indonesian Throughflow; AE, Agulhas Eddies (ITF and AE return surface water from the Pacific to the Atlantic). Circled points and crosses show water and westerly wind transports out of and into the page, respectively (with the winds as orange circles). Line thickness changes among panel largely denote changes in flow rate, with thin dashed lines representing the greatest declines from modern; in the modern, the thinner flow lines in the SNP denote weaker wind-driven upwelling than in the AZ. Double-direction arrows indicate lateral mixing between surface PAZ and OAZ in the Southern Ocean, vertical mixing across the base of the mixed layer in the AZ and SNP, and vertical (i.e., diapycnal) mixing in the ocean interior. Line colors indicate nutrient (nitrate, phosphate) concentration according to the color scale (red highest and blue lowest). All panels show the global ocean's upper and lower overturning cells (i.e., those beginning in the SAZ and PAZ, respectively). The gray scale indicates relative water densities, with light gray shading indicating the global pycnocline, the proposed poleward "slumping" of which is shown in (b) for the LGM. Additional phenomena in (b) include an equatorward shift and weakening in the westerly winds (black horizontal arrows and wind symbol size reduction) and increased dust-borne iron supply to the SAZ (brown stipples). Reprint from Sigman, Fripiat, et al. (2021), in Quat. Sci. Rev. 254, 106732

Arctic Ocean 

Fig. Seawater sampling for nitrate isotopes (red squares) in the Arctic Ocean

Reprint from Fripiat et al., 2018, Limnol. Oceanogr. 63: 2154

Nitrate isotopes suggest that a significant share of benthic denitrification is driven by nitrate supplied by remineralization and partial nitrification and most of the nitrate in the upper Arctic Ocean has been regenerated once with the Arctic (i.e., the nutrient-rich Pacific inflow). Benthic remineralization and nitrification are confining decay products (i.e., nutrients) in shelf bottom waters that are then advected throughout the basins. Nitrogen isotope composition of fossil-bound N recovered from Arctic Ocean sediment cores to provide a measure of the stratification in the Arctic Ocean

Farmer, J.R., D.M. Sigman, J. Granger, O.M. Underwood, F. Fripiat, T.M. Cronin, A. Martinez-Garcia, and G.H. Haug, 2021. Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age. Nature Geoscience 14, 684-689. doi:10.1038/s41561-021-00789-y

- Fripiat, F., M. Declercq, C.J. Sapart, L.G. Anderson, V. Bruechert, F. Deman, D. Fonseca-Batista, C. Humborg, A. Roukaerts, I.P. Semiletov, and F. Dehairs (2018). Influence of the bordering shelves on nutrient distribution in the Arctic halocline inferred from water column nitrate isotopes. Limnology and Oceanography 63: 2154-2170, doi:10.1002/lno.10930.

Fig. The colour indicates the nitrate source (blue is AHW (Atlantic-source Halocline water), red is PHW (Pacific-source Halocline water), purple is a mixture); the colour intensity indicates the nitrate concentration, with hatching indicating complete nitrate consumption and deeper shades representing higher nitrate concentrations. White lines and numbers indicate the transport of nitrate and its δ15N; black line and numbers denote sinking organic matter and its δ15N. Italicized numbers are inferred on the basis of modern observations. (a) Late-Holocene (5 - 0 ka): PHW and complete nitrate consumption in the western Arctic, and AHW and incomplete nitrate consumption in the central Arctic. (b) Holocene Thermal Maximum (10 - 5 ka): the same PHW/AHW configuration as (a), but with complete nitrate consumption across the Arctic Ocean. (c) Closed Bering Strait (before 11 ka): AHW only and incomplete nitrate consumption across the Arctic Ocean. Reprint from Farmer et al. (2021) in Nat. Geo. 14, 684-689. 

Sea Ice biogeochemistry

Fig. Representation of nitrogen dynamics in sea ice under the current paradigm and biofilm-included nutrient phytoplankton-zooplankton-detritus (NPZD) model. The current paradigm (a) of nutrient dynamics in the brine network, with inorganic nutrients (represented by inorganic nitrogen) located in the brine network where nitrate can be assimilated (Assim.), particulate organic nitrogen (PON) can be remineralized (Rem.) and ammonium can be assimilated or nitrified (Nitr.). The schematic NPZD model on the right has four different nitrogen pools: dissolved inorganic nitrogen (DIN, where DIN = NO3-+NO2-+NH4+; nutrient pool in the model), PON-P = phytoplankton, PON-Z = zooplankton, PON-D = detritus. Arrows represent the fluxes between the different pools (e.g., growth, grazing, mortality). The model includes DIN exchange with the underlying seawater through brine movement and/or diffusion. The new paradigm (B) includes a biofilm that allows for gradients between autotroph-dominated (assimilating) and heterotroph-dominating (remineralizing) communities, as well as nutrient adsorption (Ads.) on EPS and decaying organic matter. Remineralization and nitrification can also take place in brine pockets that are isolated due to clogging of the brine network by the biofilm. In the schematic biofilm-NPZD model, the nutrient pool is split into DIN in brine (DIN-brine) and DIN in biofilm (DIN-biofilm). Zigzag arrows are for diffusion between the biofilm and the surrounding brines. Brine convection represents the mixing between brines and the underlying seawater (e.g., brine convection, brine pumping, other interface processes). Color gradients in filling suggest relative intensity/concentration. Reprint from Roukaerts et al., Elem. Sci. Anh. 9:1.

How does sea ice impact the exchange of gas, matter, and energy at the ocean-atmosphere interface? 

- Roukaerts, A., F. Deman, F. Van der Linden, G. Carnat, A. Bratkic, S. Moreau, D. Lannuzel, F. Dehairs, B. Delille, J.-L. Tison, and F. Fripiat (2021). The biogeochemical role of a microbial biofilm in sea ice: Antarctic landfast sea ice as a case study. Elementa: Science of the Anthropocene 9:1. doi:10.1525/elementa.2020.00134

 

- Lannuzel, D., et al. (F. Fripiat), 2020. The future of Arctic sea-ice biogeochemistry and ice-associated ecosystems. Nature Climate Changehttps://doi.org/10.1038/s41558-020-00940-4   

 

- Carnat, G., Said-Ahmad W., Fripiat F., Wittek B., J.-L. Tison, and A. Amrani (2018). Large sulfur isotope variability suggests unique DMSP cycling and metabolism in Antarctic sea ice. Nature Communications Biology 1: 212, doi:10.1038/s42003-018-0228-y.

- Miller, L.A., F. Fripiat, B.G.T. Else, J.S. Bowman, K.A. Brown, R.E. Collins, M. Ewert, A. Fransson, M. Gosselin, D. Lannuzel, K.M. Meiners, C. Michel, J. Nishioka, D. Nomura, S. Papadimitriou, L.M. Russel, L.L. Sorensen, D.N. Thomas, J.-L. Tison, M.A. van Leeuwe, M. Vancoppenolle, E.W. Wolff, and J. Zhou (2015). Methods for biogeochemical studies of sea ice: The state of the art, caveats, and recommendations. Elementa: Science of the Anthropocene 3:000038, doi:10.12952/journal.elementa.000038.

- Fripiat, F., D.M. Sigman, S.E. Fawcett, P.A. Rafter, M.A. Weigand, and J.-L. Tison (2014). New insights into sea ice nitrogen biogeochemical dynamics from nitrogen isotopes. Global Biogeochemical Cycles 28(2), 115-130, doi:10.1002/2013GB004729.

Fig. Schematic of seasonal sea-ice biogeochemical processes in the Arctic Ocean. Black arrows represents the directionality of biogeochemical exchanges; for example, across an interface or throughout an interval. Dashed lines illustrate diffusive gradients, such as that of dissolved inorganic carbon (DIC). yellow arrows indicate solar radiation. Ice-associated and pelagic microbial communities and their grazers are represented by orange shading and symbols. The biological carbon pump links carbon exchange processes in the surface to sequestration at depth through POC and dissolved organic carbon (DOC) export, illustrated by arrows penetrating below the mixed layer (darker shading). Surface processes further impact climate active gases, such as DMS and CH4 as well as volatile organic compounds (VOC), which can contribute to the formation of cloud condensation nuclei (CCN). Reprint from Lannuzel et al., 2020, Nature Clim. Change 10, 983-992.

Subglacial biogeochemistry

                   (Work in progress)

To which extent is there in-situ production and consumption of greenhouse gases in the subglacial environment? What paleoclimatic signal can be extracted in oldest ice samples (basal ice and blue ice)? 

 

- Ardoin, L., J.-L. Tison, T. Rockmann, P.-H. Blard, T. Blunier, D. Dahl-Jensen, C. Sapart, J.P. Steffensen, and F. Fripiat (2022). Evaluating in situ microbial production of greenhouse gases in subglacial environments of the Greenland Ice Sheet: new insights from the Camp Century basal ice section. 3rd IPICS Open Science Conference in Crans-Montana, Switzerland.