Stephan Hendricks, AWECS cruise

Glaciology, Oceanography, Paleoclimatology

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

Southern Ocean, Arctic Ocean, Atmospheric Chemistry 

Laboratory Skills

  • Preparation of seawater, ice, sediments and fossils (i.e., diatoms, corals, and bivalves) for nitrogen (& oxygen) isotope ratio in reactive N with the denitrifier and chemical methods (nitrate, nitrite, ammonium, organic N, fossil bound N). 

  • Preparation of seawater, ice, sediments and fossils (i.e., diatoms) for silicon isotope ratio in dissolved and particulate matters. 

  • Trace elements and isotope analysis using Multi Collector (MC-) and Sector Field (SF-) Inductively Coupled Plasma Mass Spectrometer (ICP-MS),  Gas source Isotope Ratio Mass Spectrometer coupled to a Purge and Trap system or an Elemental Analyser. 

  • Gas concentration measurements in the cryosphere

  • Isotope tracer experiments 

  • Box (isotope) models

1/15

Field works

  • 2020              South West Indian GEOTRACES section (SWINGS), R.V. Marion Dufresne, France

  • 2019-2020    Arctic sea-ice field trip (MOSAiC), R.V. Polarstern, Germany

  • 2018              GOSHIP section in the Meditteranean Sea (MED01), R.V. A. Alvariño, Germany

  • 2018              GOSHIP section in the Bellingshausen, Amundsen, and Ross Seas (SO4P), R.V. L.M. Gould, USA

  • 2017              Antarctic sea-ice field trip (PIPERS), R.V. Nathaniel B. Palmer, USA

  • 2017              Saroma Lagoon sea-ice field trip (collaboration with Prof. D. Nomura), Japan

  • 2017              GOSHIP section in the Southern Ocean (P18S), NOAA vessel R.H. Brown, USA

  • 2016              Saroma Lagoon sea-ice field trip (collaboration with Prof. D. Nomura), Japan

  • 2016              GOSHIP section in the Southern Ocean (IO8S), R.V. R. Revelle, USA

  • 2014              Hydrographic section in the East Siberian Sea (SWERUS-C3), R.V. Oden, Sweden

  • 2014              North Atlantic GEOTRACES section (GEOVIDE), R.V. Pourquoi Pas, France

  • 2014              Hydrographic section in the subtropical North Atlantic, R.V. Belgica, Belgium

  • 2013              Antarctic sea-ice field trip (AWECS), R.V. Polarstern, Germany

  • 2012              Antarctic sea-ice field trip (SIPEX-2), R.V. Aurora Australis, Australia

  • 2011-2012    Antarctic sea-ice field trip in McMurdo Sound, Scott base, New Zealand

  • 2011              Antarctic sea-ice field trip in Dumont D’Urvilles, France

  • 2011              Hydrographic section in the Southern Ocean (KEOPS2), R.V. Marion Dufresnes, France

  • 2010              Arctic sea ice field trip, sailing vessel "SS Dagmaer Aaen", Germany

  • 2008              GEOTRACES section in the Southern Ocean (BONUS-GOODHOPE), R.V. Marion Dufresnes, France

  • 2007              Hydrographic section in the Southern Ocean (SAZ-SENSE), R.V. Aurora Australis, Australia

Recent or ongoing projects

Ocean dynamic and nitrate isotopes

Fig. Nitrate isotope database in the Ocean (collaboration with D. Marconi and D.M. Sigman, Princeton University, USA). Grayscale is for surface nitrate concentration.

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

- 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.

- Fripiat, F., Marconi, D., Martinez-Garcia, A., S.E. Fawcett, D.M. Sigman and G.H. Haug (2018). Pycnocline recipe revisited using the nitrate isotopes: New estimates for the overturning ratio and low-latitude nutrient supply. AGU Fall meeting 2018, Washington DC, USA.

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

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.

 

- 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

- 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.

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.

- Sigman, D.M., F. Fripiat, A. Studer, P.C. Kemeny, A. Martinez-Garcia, M.P. Hain, X. Wang, H. Ren, and G.H. Haug (2019). The role of the Southern Ocean modulation of atmospheric CO2 over glacial cycles: A review of the ‘Antarctic separation’ hypothesis, with inferences from the North Pacific. Submitted in Quaternary Science Reviews. 

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.

Fig. Published fossil-bound N isotope records (filled squares) vs. the ones on which I am working on at the Max Planck Institute for Chemistry (empty squares). Seawater samples are shown with circles. Surface nitrate concentration in grayscale. Collaboration with L. Armand (Australian National University), F. Lamy (Alfred Wegener Institute), S. Moreau (Norwegian Polar Institute), and D.M. Sigman (Princeton University)

Fig. Example of fossil bound N isotope record (here diatom-bound) in the Pacific sector of the Southern Ocean, showing a tight connection with Antarctic Climate

(Studer et al., 2015, Paloceanography  30: 845-862)

Influence of the bordering shelves on nutrient distribution in the 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.

- 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.

Sea Ice biogeochemistry

Isotopic tracers of metabolic pathways 

Biogeochemical dynamic distinct to its oceanic counterpart

- 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.

 

- 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.

Large scale compilation (nutrients and biomass) to infer large cale pattern and carbon flux.

e.g., Conservative estimate of 35 Tg C yr-1 for Antarctic sea-ice primary productivy

F. Deman (2018; unpublished results)

- 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 

 

- 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.

Subglacial biogeochemistry

                   (Work in progress)

Isotopic tracers of metabolic pathways 

In situ greenhouse gas production and interference with the paleoclimatic signal (basal ice)

New archives for the Anthropocene

(work in progress)

Nitrate isotopes in ice cores

(Picture from Prof. Jean-Louis Tison, ULB)

(collaboration with Prof. Jean-Louis Tison, ULB)

Annual increment of calcium carbonate in Arctica islandica

(reprinted from Schöne et al., 2013, Global Planet. Change 111: 299-225)

Fossil bound N isotope ratio (collaboration with B. Schöne, JGU Mainz University)

© 2018 by François Fripiat

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