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Iceberg-induced changes to polynya operation and regional oceanography in the southern Ross Sea, Antarctica, from in situ observations

Published online by Cambridge University Press:  14 May 2012

N.J. Robinson  and
M.J.M. Williams
N.J. Robinson*
Affiliation:
National Institute of Water & Atmospheric Research, 301 Evans Bay Parade, Wellington 6021, New Zealand Departments of Marine Science and Physics, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
M.J.M. Williams
Affiliation:
National Institute of Water & Atmospheric Research, 301 Evans Bay Parade, Wellington 6021, New Zealand
*
[email protected]
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Abstract

Two massive tabular icebergs calved from the Ross Ice Shelf in 2000 (B-15) and 2002 (C-19) and perturbed regional ocean processes for several years. Here we document the ocean's response in McMurdo Sound to the icebergs using in situ data collected before, during and after the icebergs’ residence in the Ross Sea. Departures from typical McMurdo Sound seasonal oceanography included the non-appearance of Antarctic Surface Water in summer, a cooler and more homogeneous water column during winter and ‘super-fresh’ High Salinity Shelf Water that gradually recovered its salinity. We found that each iceberg triggered a distinct response to regional ocean processes. B-15a, the largest piece of iceberg B-15, restricted surface circulation, cooled and freshened the upper water column and reduced melting near the ice shelf front for four years. Iceberg C-19 interrupted the operation of the Ross Sea polynya, from which McMurdo Sound took three to four years to recover, and was responsible for a geographic shift in the dense water formation region for the south-western Ross Sea. These results differ from earlier modelling studies and highlight the challenges of modelling the polar ocean. We also show that one pathway previously thought to supply dense water to the Ross Ice Shelf cavity was not operating at that time.

Keywords

iceberg perturbationice-ocean interactionice shelf waterMcMurdo Soundocean circulation
Type
Physical Sciences
Information
Antarctic Science , Volume 24 , Issue 5 , 13 September 2012 , pp. 514 - 526
Copyright
Copyright © Antarctic Science Ltd 2012

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References

Ainley, D.G., Ballard, G.Olmastroni, S. 2009. An apparent decrease in the prevalence of “Ross Sea Killer Whales” in the southern Ross Sea. Aquatic Mammals, 35, 335–347.CrossRefGoogle Scholar
Albrecht, N., Vennell, R., Williams, M., Stevens, C., Langhorne, P., Leonard, G.Haskell, T. 2006. Observation of sub-inertial internal tides in McMurdo Sound, Antarctica. Geophysical Research Letters, 10.1029/2006GL027377.CrossRefGoogle Scholar
Arrigo, K.R.van Dijken, G.L. 2003. Impact of iceberg C-19 on Ross Sea primary production. Geophysical Research Letters, 30, 10.1029/2003GL017721.CrossRefGoogle Scholar
Arrigo, K.R.van Dijken, G.L. 2004. Annual changes in sea ice, chlorophyll a, and primary production in the Ross Sea, Antarctica. Deep-Sea Research II, 51, 117–138.CrossRefGoogle Scholar
Arrigo, K.R., van Dijken, G.L., Ainely, D.G., Fahnestock, M.A.Markus, T. 2002. Ecological impact of a large Antarctic iceberg. Geophysical Research Letters, 10.1029/2001GL014160.CrossRefGoogle Scholar
Assmann, K.M. 2004. The effect of McMurdo Sound topography on water mass exchange across the Ross Ice Shelf front. Bergen: Bjerknes Centre for Climate Research. Forum for Research into Ice Shelf Processes (FRISP) Report, 15, 55–69.Google Scholar
Assmann, K.Timmermann, R. 2005. Variability of dense water formation in the Ross Sea. Ocean Dynamics, 55, 68–87.CrossRefGoogle Scholar
Assmann, K., Hellmer, H.H.Beckmann, A. 2003. Seasonal variation in circulation and water mass distribution on the Ross Sea continental shelf. Antarctic Science, 15, 3–11.CrossRefGoogle Scholar
Brunt, K.M., Sergienko, O.MacAyeal, D.R. 2006. Observations of unusual fast-ice conditions in the southwest Ross Sea, Antarctica: preliminary analysis of iceberg and storminess effects. Annals of Glaciology, 44, 183–187.CrossRefGoogle Scholar
Cockrem, J., Potter, M.Candy, E. 2006. Corticosterone in relation to body mass in Adelie penguins (Pygoscelis adeliae) affected by unusual sea ice conditions at Ross Island, Antarctica. General and Comparative Endocrinology, 149, 244–252.CrossRefGoogle ScholarPubMed
Dinniman, M.S., Klink, J.M.Smith, W.O. Jr 2007. The influence of sea ice cover and icebergs on circulation and water mass formation in a numerical circulation model of the Ross Sea, Antarctica. Journal of Geophysical Research, 10.1029/2006JC004036.CrossRefGoogle Scholar
Fusco, G., Budillon, G.Spezie, G. 2009. Surface heat fluxes and thermohaline variability in the Ross Sea and in Terra Nova Bay polynya. Continental Shelf Research, 29, 1887–1895.CrossRefGoogle Scholar
Gordon, A.L., Orsi, A.H., Muench, R., Huber, B.A., Zambianchi, E.Visbeck, M. 2009. Western Ross Sea continental slope gravity currents. Deep-Sea Research II, 56, 796–817.CrossRefGoogle Scholar
Grosfeld, K., Gerdes, R.Determann, J. 1997. Thermohaline circulation and interaction between ice shelf cavities and the adjacent open ocean. Journal of Geophysical Research, 102, 15 595–15 610.CrossRefGoogle Scholar
Harangozo, S.A.Connolley, W.M. 2006. The role of the atmospheric circulation in the record minimum extent of open water in the Ross Sea in the 2003 austral summer. Atmosphere-Ocean, 44, 83–97.CrossRefGoogle Scholar
Horgan, H., Naish, T., Bannister, S., Balfour, N.Wilson, G. 2005. Seismic stratigraphy of the Plio-Pleistocene Ross Island flexural moat-fill: a prognosis for ANDRILL Program drilling beneath McMurdo-Ross Ice Shelf. Global and planetary change, 45, 83–97.CrossRefGoogle Scholar
Hunt, B.M., Heofling, K.Cheng, C.C. 2003. Annual warming episodes in seawater temperature in McMurdo Sound in relationship to endogenous ice in notothenioid fish. Antarctic Science, 15, 333–338.CrossRefGoogle Scholar
Jacobs, S.S.Giulivi, C.F. 1998. Interannual ocean and sea ice variability in the Ross Sea. Antarctic Research Series, 75, 135–150.Google Scholar
Jacobs, S.S., Fairbanks, R.G.Horibe, Y. 1985. Origin and evolution of water masses near the Antarctic continental margin: evidence from H182 O/ H162 O ratios in seawater. Antarctic Research Series, 43, 59–85.CrossRefGoogle Scholar
Jacobs, S.S., Giulivi, C.F.Mele, P.A. 2002. Freshening of the Ross Sea during the late 20th century. Science, 297, 386–389.CrossRefGoogle ScholarPubMed
Jacobs, S.S., Gordon, A.L.Ardai, J. 1979. Circulation and melting beneath the Ross Ice Shelf. Science, 203, 439–443.CrossRefGoogle ScholarPubMed
Joughin, I.MacAyeal, D.R. 2005. Calving of large tabular icebergs from ice shelf rift systems. Geophysical Research Letters, 10.1029/2004GL020978.CrossRefGoogle Scholar
Kenneally, J.P.Hughes, T. 2006. Calving giant icebergs: old principles, new applications. Antarctic Science, 18, 409–419.CrossRefGoogle Scholar
Kern, S. 2009. Wintertime Antarctic coastal polynya area: 1992 to 2008. Geophysical Research Letters, 10.1029/2009GL038062.CrossRefGoogle Scholar
Keys, H.J.R., Jacobs, S.S.Barnett, D. 1990. The calving and drift of iceberg B-9 in the Ross Sea, Antarctica. Antarctic Science, 2, 243–257.CrossRefGoogle Scholar
Kooyman, G.L., Ainley, D.G., Ballard, G.Ponganis, P.J. 2007. Effects of giant icebergs on two emperor penguin colonies in the Ross Sea, Antarctica. Antarctic Science, 19, 31–38.CrossRefGoogle Scholar
Kurtz, D.D.Bromwich, D.H. 1985. A recurring, atmospherically forced polynya in Terra Nova Bay. Antarctic Research Series, 43, 177–201.CrossRefGoogle Scholar
Leonard, G.H., Purdie, C.R., Langhorne, P.J., Haskell, T.G., Williams, M.J.M.Frew, R.D. 2006. Observations of platelet ice growth and oceanographic conditions during the winter of 2003 in McMurdo Sound, Antarctica. Journal of Geophysical Research, 10.1029/2005JC002952.CrossRefGoogle Scholar
Leonard, G.H., Langhorne, P.J., Williams, M.J.M., Vennell, R., Purdie, C.R., Dempsey, D.E., Haskell, T.G.Frew, R.D. 2011. Evolution of supercooling under coastal Antarctic sea ice during winter. Antarctic Science, 23, 399–409.CrossRefGoogle Scholar
Lewis, E.L.Perkin, R.G. 1985. The winter oceanography of McMurdo Sound, Antarctica. Antarctic Research Series, 43, 145–165.CrossRefGoogle Scholar
MacAyeal, D.R., Okal, M.H., Thom, J.E., Brunt, K.M., Kim, Y.-J.Bliss, A.K. 2008. Tabular iceberg collisions within the coastal regime. Journal of Glaciology, 54, 371–386.CrossRefGoogle Scholar
Mahoney, A.R., Gough, A.J., Langhorne, P.J., Robinson, N.J., Stevens, C.L., Williams, M.M.J.Haskell, T.G. 2011. The seasonal appearance of ice shelf water in coastal Antarctica and its effect on sea ice growth. Journal of Geophysical Research, 10.1029/2011JC007060.CrossRefGoogle Scholar
Martin, S., Drucker, R.S.Kwok, R. 2007. The areas and ice production of the western and central Ross Sea polynyas, 1992–2002, and their relation to the B-15 and C-19 iceberg events of 2000 and 2002. Journal of Marine Systems, 68, 201–214.CrossRefGoogle Scholar
McCrae, I.R. 1984. A summary of glaciological measurements made between 1960 and 1984 on the McMurdo Ice Shelf, Antarctica. School of Engineering Report 360. Auckland: Department of Theoretical and Applied Mechanics, University of Auckland, 93 pp.Google Scholar
McKay, R., Dunbar, G., Naish, T., Barrett, P., Carter, L.Harper, M. 2008. Retreat history of the Ross Ice Sheet (Shelf) since the Last Glacial Maximum from deep-basin sediment cores around Ross Island. Palaeogeography, Palaeoclimatology, Palaeoecology, 260, 245–261.CrossRefGoogle Scholar
Orsi, A.H.Wiederwohl, C.L. 2009. A recount of Ross Sea waters. Deep-Sea Research II, 56, 778–795.CrossRefGoogle Scholar
Pyne, A.R., Ward, B.L., MacPherson, A.J.Barrett, P.J. 1985. McMurdo Sound bathymetry. New Zealand Oceanographic Institute Chart, Miscellaneous Series, No. 62. 1:250 000. Wellington: Oceanographic Institute, Antarctic Research Centre.Google Scholar
Remy, J.-P., Becquevort, S., Haskell, T.G.Tison, J.-L. 2008. Impact of the B-15 iceberg “stranding event” on the physical and biological properties of sea ice in McMurdo Sound, Ross Sea, Antarctica. Antarctic Science, 20, 593–604.CrossRefGoogle Scholar
Robinson, N.J. 2012. Circulation, mixing and interactions in the ocean near an Antarctic ice shelf. PhD thesis, University of Otago, 249 pp. [Unpublished.]Google Scholar
Robinson, N.J., Williams, M.J.M., Barrett, P.J.Pyne, A.R. 2010. Observations of flow and ice-ocean interaction beneath the McMurdo Ice Shelf, Antarctica. Journal of Geophysical Research, 10.1029/2008JC005255.CrossRefGoogle Scholar
Seibel, B.A.Dierssen, H.M. 2003. Cascading trophic impacts of reduced biomass in the Ross Sea, Antarctica: just the tip of the iceberg? Biology Bulletin, 205, 93–97.CrossRefGoogle ScholarPubMed
Silva, T.A.M., Bigg, G.R.Nicholls, K.W. 2006. Contribution of giant icebergs to the Southern Ocean freshwater flux. Journal of Geophysical Research, 10.1029/2004JC002843.CrossRefGoogle Scholar
Tamura, T., Ohshima, K.I.Nihashi, S. 2008. Mapping of sea ice production for Antarctic coastal polynyas. Geophysical Research Letters, 10.1029/2010JC006586.CrossRefGoogle Scholar
Tressler, W.L.Ommundsen, A.M. 1962. Seasonal oceanographic studies in McMurdo Sound, Antarctica. Technical report. Washington DC: United States Navy Hydrographic Offce, 158 pp.Google Scholar
Turnbull, I.D. 2010. Drift of large tabular icebergs in response to atmospheric surface pressure gradients, an observational study. Antarctic Science, 22, 199–208.CrossRefGoogle Scholar
Van Woert, M.L. 1999. Wintertime expansion and contraction of the Terra Nova Bay polynya. In Spezie, G. & Manzella, G.M.R., eds. Oceanography of the Ross Sea, Antarctica. Milan: Springer, 145–164.Google Scholar