Abstract
The Southern Ocean surrounds the Antarctic continent and supports one of the most productive marine ecosystems. Migratory and endemic species of whales, seals and birds benefit from the high biomass of their principal prey, krill (Euphausia superba) and cephalopods, in this area. Most species of baleen whales and male sperm whales in the Southern Hemisphere migrate between low-latitude breeding grounds in winter and highly productive Antarctic feeding grounds in summer. Here I show the importance of the southernmost reaches of the strongest ocean current, the Antarctic Circumpolar Current (ACC), to a complex and predictable food web of the Southern Ocean. The circumpolar distributions of blue, fin and humpback whales from spring to midsummer trace the non-uniform high-latitude penetration of shoaled, nutrient-rich Upper Circumpolar Deep Water, which is carried eastward by the ACC. The poleward extent of this water mass delineates the Southern Boundary1 of the ACC and corresponds not only to the circumpolar distributions of baleen whales, but also to distributions of krill and to regions of high, seasonally averaged, phytoplankton biomass. Sperm whales, which feed on cephalopods2, also congregate in highest densities near the Southern Boundary. The association of primary production, Krill, and whales with the Southern Boundary, suggests that it provides predictably productive foraging for many species, and is of critical importance to the function of the Southern Ocean ecosystem.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Orsi, A. H., Whitworth, T. II & Nowlin, W. D. J On the meridional extent and fronts of the Antarctic Circumpolar Current. Deep-Sea Res. I 42, 641–673 (1995).
Clarke, M. R. Cephalopoda in the diet of sperm whales of the Southern Hemisphere and their bearing on sperm whale biology. Discov. Rep. 37, 1–324 (1980).
Sievers, H. A. & Nowlin, W. D. J The stratification and water masses at Drake Passage. J. Geophys. Res. 89, 10489–10514 (1984).
Comiso, J. C. et al. Coastal zone color scanner pigment concentrations in the Southern Ocean and relationships to geophysical surface features. J. Geophys. Res. 98, 2419–2451 (1993).
de Baar, H. J. W. et al. Importance of iron for plankton blooms and carbon dioxide drawdown in the Southern Ocean. Nature 373, 412–415 (1995).
Marr, J. W. S. The natural history and geography of the Antarctic krill (Euphausia superba Dana). Disov. Rep. 32, 33–464 (1962).
Siegel, V. & Loeb, V. Recruitment of Antarctic krill Euphausia superba and possible causes for its variability. Mar. Ecol. Prog. Ser. 123, 45–56 (1995).
Priddle, J. et al. in Antarctic Ocean and Resources Variability (ed. Sahrhage, D.) 169–182 (Springer, Berlin, 1988).
Laws, R. M. The ecology of the Southern Ocean. Am. Sci. 73, 26–40 (1985).
Hofmann, E. E. et al. Models of the early life history of Euphausia superba — Part I. Time and temperature dependence during the descent-ascent cycle. Deep-Sea Res. 39, 1177–1200 (1992).
Ribic, C. A., Ainley, D. G. & Fraser, W. R. Habitat selection by marine mammals in the marginal ice zone. Ant. Sci. 3, 181–186 (1991).
de la Mare, W. K. Abrupt mid-twentieth-century decline in Antarctic sea-ice extent from whaling records. Nature 389, 57–59 (1997).
Smith, W. O. Jr & Nelson, D. M. Importance of ice edge phytoplankton production in the Southern Ocean. BioScience 36, 251–257 (1986).
Orsi, A. H., Nowlin, W. D. Jr. & Whitworth, T. II On the circulation and stratification of the Weddell Gyre. Deep-Sea Res. I 40, 169–203 (1993).
Locarnini, R. A. Water Masses and Circulation in the Ross Gyre and Environs (thesis, Texas A&M Univ. 1994).
Rodhouse, P. G. & White, M. G. Cephalopods occupy the ecological niche of epipelagic fish in the Antarctic Polar Frontal Zone. Biol. Bull. 189, 77–80 (1995).
Mizroch, S. A., Rice, D. W. & Larson, S. W. Distribution of Rorquals in the Southern Ocean: An Atlas based on Pelagic Catch Data (Fishery Bull., in the press).
Holm, J. L. & Jonsgård, Å Occurrence of the sperm whale in the Antarctic and the possible influence of the moon. The Norwegian Whaling Gazette 4, 161–182 (1959).
Gloersen, P. et al. Arctic and Antarctic Sea Ice, 1978–1987: Satellite Passive-Microwave Observations and Analysis (NASA SP-511) (NASA, Washington DC, 1992).
Acknowledgements
I thank D. P. DeMaster, R. L. Gentry, G. L. Kooyman, D. G. M. Miller, A. H. Orsi and J. Priddle for review of the manuscript, and A. H. Orsi for discussions and for providing the coordinates of the Southern Boundary of the ACC.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tynan, C. Ecological importance of the Southern Boundary of the Antarctic Circumpolar Current. Nature 392, 708–710 (1998). https://doi.org/10.1038/33675
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/33675
This article is cited by
-
Predicting impacts of climate change on the biogeographic patterns of representative species richness in Prydz Bay-Amery Ice Shelf
Journal of Oceanology and Limnology (2023)
-
DNA barcoding provides insights into Fish Diversity and Molecular Taxonomy of the Amundsen Sea
Conservation Genetics Resources (2022)
-
Massive Southern Ocean phytoplankton bloom fed by iron of possible hydrothermal origin
Nature Communications (2021)
-
Density and distribution of euphausiid larvae in the Scotia Sea in the 2011 summer
Polar Biology (2021)
-
Cetacean distribution in relation to environmental parameters between Drake Passage and northern Antarctic Peninsula
Polar Biology (2020)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.