Letter

Ocean access to a cavity beneath Totten Glacier in East Antarctica

Received:
Accepted:
Published online:

Abstract

Totten Glacier, the primary outlet of the Aurora Subglacial Basin, has the largest thinning rate in East Antarctica1,2. Thinning may be driven by enhanced basal melting due to ocean processes3, modulated by polynya activity4,5. Warm modified Circumpolar Deep Water, which has been linked to glacier retreat in West Antarctica6, has been observed in summer and winter on the nearby continental shelf beneath 400 to 500 m of cool Antarctic Surface Water7,8. Here we derive the bathymetry of the sea floor in the region from gravity9 and magnetics10 data as well as ice-thickness measurements11. We identify entrances to the ice-shelf cavity below depths of 400 to 500 m that could allow intrusions of warm water if the vertical structure of inflow is similar to nearby observations. Radar sounding reveals a previously unknown inland trough that connects the main ice-shelf cavity to the ocean. If thinning trends continue, a larger water body over the trough could potentially allow more warm water into the cavity, which may, eventually, lead to destabilization of the low-lying region between Totten Glacier and the similarly deep glacier flowing into the Reynolds Trough. We estimate that at least 3.5 m of eustatic sea level potential drains through Totten Glacier, so coastal processes in this area could have global consequences.

  • Subscribe to Nature Geoscience for full access:

    $59

    Subscribe

Additional access options:

Already a subscriber?  Log in  now or  Register  for online access.

References

  1. 1.

    & Dynamic thinning of Antarctic glaciers from along-track repeat radar altimetry. J. Glaciol. 58, 830–840 (2012).

  2. 2.

    , , & Extensive dynamic thinning on the margins of the Greenland and Antarctic ice sheets. Nature 461, 971–975 (2009).

  3. 3.

    et al. Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature 484, 502–505 (2012).

  4. 4.

    , , & Simulated melt rates for the Totten and Dalton ice shelves. Ocean Sci. Discuss. 10, 2109–2140 (2013).

  5. 5.

    et al. Observed thinning of Totten Glacier is linked to coastal polynya variability. Nature Commun. 4, 2857 (2013).

  6. 6.

    et al. Observations beneath Pine Island Glacier in West Antarctica and implications for its retreat. Nature Geosci. 3, 468–472 (2010).

  7. 7.

    , & On the circulation and water masses over the Antarctic continental slope and rise between 80 and 150° E. Deep Sea Res. 47, 2299–2326 (2000).

  8. 8.

    et al. Late winter oceanography off the Sabrina and BANZARE coast (117–128° E), East Antarctica. Deep Sea Res. 58, 1194–1210 (2011).

  9. 9.

    The rapid calculation of potential anomalies. Geophys. J. R. Astron. Soc. 31, 447–455 (1973).

  10. 10.

    et al. The subglacial geology of Wilkes Land, East Antarctica. Geophys. Res. Lett. 41, 2390–2400 (2014).

  11. 11.

    et al. A dynamic early East Antarctic Ice Sheet suggested by ice-covered fjord landscapes. Nature 474, 72–75 (2011).

  12. 12.

    , & Potential Antarctic Ice Sheet retreat driven by hydrofracturing and ice cliff failure. Earth Planet. Sci. Lett. 412, 112–121 (2015).

  13. 13.

    , , & The cavity under the Amery Ice Shelf, East Antarctica. J. Glaciol. 54, 881–887 (2008).

  14. 14.

    , & Antarctic grounding line mapping from differential satellite radar interferometry. Geophys. Res. Lett. 38, L10504 (2011).

  15. 15.

    & Antarctic Coastlines and Grounding Line Derived from MODIS Mosaic of Antarctica (MOA) (National Snow and Ice Data Center, 2011);

  16. 16.

    , & Variability of basal melt beneath the Pine Island Glacier Ice Shelf, West Antarctica. J. Glaciol. 57, 581–595 (2011).

  17. 17.

    Depth and density of the Antarctic firn layer. Arct. Antarct. Alp. Res. 40, 432–438 (2008).

  18. 18.

    , , , & MODIS-based Mosaic of Antarctica (MOA) data sets: Continent-wide surface morphology and snow grain size. Remote Sens. Environ. 111, 242–257 (2007).

  19. 19.

    Radio echo determination of basal roughness characteristics on the Ross Ice Shelf. Ann. Glaciol. 3, 216–221 (1982).

  20. 20.

    Dielectric behaviour of heterogeneous systems. Prog. Dielectr. 7, 69–114 (1967).

  21. 21.

    , & Analysis techniques for coherent airborne radar sounding: Application to West Antarctic ice streams. J. Geophys. Res. 110, B06303 (2005).

  22. 22.

    , & Evidence for a water system transition beneath Thwaites Glacier, West Antarctica. Proc. Natl Acad. Sci. USA 110, 12225–12228 (2013).

  23. 23.

    Flexure of a floating ice tongue. J. Glaciol. 8, 385–397 (1969).

  24. 24.

    Tidal flexure at ice shelf margins. J. Geophys. Res. 100, 6213–6224 (1995).

  25. 25.

    Mass balance of East Antarctic glaciers and ice shelves from satellite data. Ann. Glaciol. 34, 217–227 (2002).

  26. 26.

    et al. Bedmap2: Improved ice bed, surface and thickness datasets for Antarctica. Cryosphere 7, 375–393 (2013).

  27. 27.

    et al. The International Bathymetric Chart of the Southern Ocean (IBCSO) Version 1.0—A new bathymetric compilation covering circum-Antarctic waters. Geophys. Res. Lett. 40, 3111–3117 (2013)

  28. 28.

    , , & Accelerated Antarctic ice loss from satellite gravity measurements. Nature Geosci. 2, 859–862 (2009)

  29. 29.

    , , & Reassessment of the potential sea-level rise from a collapse of the West Antarctic Ice Sheet. Science 324, 901–903 (2009).

  30. 30.

    et al. Land-ice elevation changes from photon-counting swath altimetry: First applications over the Antarctic Ice Sheet. J. Glaciol. 61, 17–28 (2015).

Download references

Acknowledgements

This project is the result of the ongoing ICECAP collaboration between the USA, UK and Australia with support from NSF grants PLR-0733025 and PLR-1143843, and CDI-0941678, NASA grants NNG10HPO6C and NNX11AD33G (Operation Ice Bridge and the American Recovery and Reinvestment Act), Australian Antarctic Division projects 3013 and 4077, NERC grant NE/D003733/1, the G. Unger Vetlesen Foundation, the Jackson School of Geosciences, and the Antarctic Climate and Ecosystems Cooperative Research Centre. We thank the captains and crews of Kenn Borek Airlines Ltd, ICECAP project participants, CMG Operations Pty Ltd, and the Geosoft Education Program. We also thank S. Kempf for assistance with radar data processing, as well as A. Leventer, A. Wåhlin, D. Gwyther, K. Soderlund, C. Grima, F. Habbal and S. Zedler for comments on the manuscript. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. This is UTIG contribution 2831.

Author information

Affiliations

  1. Institute for Geophysics, University of Texas at Austin, Austin, Texas 78758, USA

    • J. S. Greenbaum
    • , D. D. Blankenship
    • , D. A. Young
    •  & T. G. Richter
  2. Antarctic Climate & Ecosystems Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, Tasmania 7001, Australia

    • J. L. Roberts
    • , B. Legresy
    • , R. C. Warner
    •  & T. D. van Ommen
  3. Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia

    • J. L. Roberts
    • , R. C. Warner
    •  & T. D. van Ommen
  4. School of Earth and Environment, The University of Western Australia, Perth, Western Australia 6009, Australia

    • A. R. A. Aitken
  5. CSIRO Oceans and Atmosphere Flagship, Castray Esplanade, Hobart, Tasmania 7000, Australia

    • B. Legresy
  6. CNRS-LEGOS, 14 Av. E. Belin, 31400, Toulouse, France

    • B. Legresy
  7. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA

    • D. M. Schroeder
  8. Grantham Institute and Department of Earth Sciences and Engineering, Imperial College London, London SW7 2AZ, UK

    • M. J. Siegert

Authors

  1. Search for J. S. Greenbaum in:

  2. Search for D. D. Blankenship in:

  3. Search for D. A. Young in:

  4. Search for T. G. Richter in:

  5. Search for J. L. Roberts in:

  6. Search for A. R. A. Aitken in:

  7. Search for B. Legresy in:

  8. Search for D. M. Schroeder in:

  9. Search for R. C. Warner in:

  10. Search for T. D. van Ommen in:

  11. Search for M. J. Siegert in:

Contributions

J.S.G. performed the gravity inversions, magnetic depth to basement estimates, hydrostatic analysis, applied the bed reflectivity corrections, and wrote the manuscript. D.D.B., D.A.Y. and A.R.A.A. assisted with the potential field interpretations. J.S.G. and T.G.R. performed the initial gravity reduction and J.S.G. levelled the result. J.L.R. estimated the sea level potential for Totten Glacier. B.L. computed the percentage deflection expected for a range of trough widths and commented on what would be detectable using existing ERS data. D.M.S. provided radar technical and interpretation guidance for the discussion of reflectivity and specularity. A.R.A.A. performed the magnetics data reduction. J.L.R., R.C.W. and T.D.v.O. provided the glaciological context for Totten Glacier. J.S.G., D.A.Y., D.D.B., T.D.v.O., J.L.R., M.J.S. and R.C.W. designed the surveys. J.S.G., D.A.Y., T.D.v.O., J.L.R. and R.C.W. collected the data. All authors contributed comments to the interpretation of results and preparation of the final paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to J. S. Greenbaum.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information