A dominant Antarctic ecological paradigm suggests that winter sea ice is generally the main feeding ground for krill larvae. Observations from our winter cruise to the southwest Atlantic sector of the Southern Ocean contradict this view and present the first evidence that the pack-ice zone is a food-poor habitat for larval development. In contrast, the more open marginal ice zone provides a more favourable food environment for high larval krill growth rates. We found that complex under-ice habitats are, however, vital for larval krill when water column productivity is limited by light, by providing structures that offer protection from predators and to collect organic material released from the ice. The larvae feed on this sparse ice-associated food during the day. After sunset, they migrate into the water below the ice (upper 20 m) and drift away from the ice areas where they have previously fed. Model analyses indicate that this behaviour increases both food uptake in a patchy food environment and the likelihood of overwinter transport to areas where feeding conditions are more favourable in spring.

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We thank the captain and crew of RV Polarstern expedition WISKY (ANTXXIX-7) as well as our helicopter teams for their excellent support with work at sea, R. Schlicht for statistical consultation and B. Raymond for technical contribution to present results. This work was funded by the PACES (Polar Regions and Coasts in a changing Earth System) programme (Topic 1, WP 5) of the Helmholtz Association. Additional funds were made available via the Helmholtz Virtual Institute ‘PolarTime’ (VH-VI-500: Biological timing in a changing marine environment—clocks and rhythms in polar pelagic organisms) and the Australian Government through Antarctic Science grant #4073 and the Antarctic Climate and Ecosystem Cooperative Research Centre. S.E.T. and E.J.M. were funded by the Natural Environment Research Council under British Antarctic Survey National Capability-Ecosystems. The surface velocity data were produced by Ssalto/Duacs and distributed by Aviso, with support from Cnes (http://www.aviso.altimetry.fr/duacs/). TerraSAR-X images used to identify sampling sites were provided by German Space Agency (DLR) via the proposal “Investigation of the role of sea ice and snow properties on Antarctic krill distribution and condition in winter/spring”. We thank T. Busche (DLR) and E. Schwarz (DLR) for organizing near-real time image delivery on board of Polarstern.

Author information


  1. Department of Biosiences, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Polar Biological Oceanography, Bremerhaven, Germany

    • Bettina Meyer
    • , Ulrich Freier
    • , Christine Klaas
    • , Laura Halbach
    •  & Mathias Teschke
  2. Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Oldenburg, Germany

    • Bettina Meyer
  3. Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg, Oldenburg, Germany

    • Bettina Meyer
  4. SC-Scientific Consulting, Neuss, Germany

    • Ulrich Freier
  5. Department of Ecological Modelling, Helmholtz Centre for Environmental Research—UFZ, Leipzig, Germany

    • Volker Grimm
  6. Institute of Forest Growth and Computer Science, Technische Universität Dresden, Tharandt, Germany

    • Jürgen Groeneveld
  7. Department of Earth and Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada

    • Brian P. V. Hunt
    •  & Evgeny Pakhomov
  8. Hakai Institute, Heriot Bay, British Columbia, Canada

    • Brian P. V. Hunt
  9. Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada

    • Brian P. V. Hunt
    •  & Evgeny Pakhomov
  10. Department of Agriculture, Forestry and Fisheries, Fisheries Research and Development, Cape Town, South Africa

    • Sven Kerwath
    •  & Lutz Auerswald
  11. Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa

    • Sven Kerwath
  12. Department of Animal Sciences, Stellenbosch University, Stellenbosch, South Africa

    • Sven Kerwath
    •  & Lutz Auerswald
  13. Department of the Environment and Energy, Australian Antarctic Division, Kingston, Tasmania, Australia

    • Rob King
    • , Klaus M. Meiners
    • , Jessica Melbourne-Thomas
    • , Simon Jarman
    • , So Kawaguchi
    •  & Michael Sumner
  14. Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tasmania, Australia

    • Klaus M. Meiners
    • , Jessica Melbourne-Thomas
    • , So Kawaguchi
    • , Michael Sumner
    •  & Rowan Trebilco
  15. British Antarctic Survey, Natural Environment Research Council, Cambridge, UK

    • Eugene J. Murphy
    •  & Sally E. Thorpe
  16. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA

    • Sharon Stammerjohn
  17. Department of Biosiences, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Marine BioGeoScience, Bremerhaven, Germany

    • Dieter Wolf-Gladrow
    •  & Gernot Nehrke
  18. South African Environmental Observation Network, Elwandle Node, Grahamstown, South Africa

    • Albrecht Götz
  19. Department of Ichthyology and Fisheries Science, Rhodes University, Grahamstown, South Africa

    • Albrecht Götz
  20. Zoology Department, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa

    • Albrecht Götz
  21. Trace and Environmental DNA (TrEnD) Laboratory, Department of Environment and Agriculture, Curtin University, Bentley, Western Australia, Australia

    • Simon Jarman
  22. Department Climate Sciences, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Section Sea Ice Physics, Bremerhaven, Germany

    • Thomas Krumpen
    •  & Robert Ricker
  23. Institute of Marine Sciences and Management, Istanbul University, Istanbul, Turkey

    • Noyan I. Yilmaz


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B.M. and U.F. designed the research and B.M. wrote the paper with support from the co-authors. U.F., S.K. and A.G. designed the scientific dive operations with support from I.N.Y., G.N., M.T. and L.A. Ice physical investigations were performed by T.K., R.R., K.M.M. and S.S. The foraging model was designed by J.G. with support from V.G. S.E.T. and E.J.M. worked on the advection model, whereas J.M.-T., R.T., M.S., S.K. and K.M.M. performed the sea-ice model. Larval krill morphology, physiology and abundance data were collected and processed by R.K., L.H., E.P., B.P.V.H., M.T., S.J. and B.M. Sea-ice biology data were collected and analysed by L.H., B.M. and K.M.M. The climatology and water column data were collected and processed by C.K. and D.W.-G.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Bettina Meyer.

Electronic supplementary material

  1. Supplementary Information

    Supplementary Figures 1–11, Supplementary Tables 1–2, Supplementary Methods.

  2. Life Sciences Reporting Summary

  3. Supplementary Video 1

    Patchiness and behaviour of larvae under sea ice during the day in the pack-ice zone.

  4. Supplementary Video 2

    Patchiness and behaviour of larvae in the marginal ice zone during sunset, larvae starting to leave the ice to be dispersed in the water column.

  5. Supplementary Video 3

    Larval krill feeding on a horizontal ice floe (“terrace”).

  6. Supplementary Video 4

    Larval krill feeding on the under-side of sea ice, frozen overnight at the diving hole.

  7. Supplementary Video 5

    Larval krill dispersed in the water column during night in the pack-ice zone.