Abstract
Spencer Gulf, South Australia, forms a remarkable natural system in which marine gravity currents are regularly observed. The most intense of these forms every autumn, when the gulf waters, which are of high salinity after summer evaporation, are cooled to the point where they are much denser than the waters on the shelf. They then slip out of the gulf along the sea floor to be replaced by a surface inflow of less saline shelf water. Here we report the first complete survey of this outflow during a period when salt exchange was both intense and well-defined. The gravity current has been traced across the floor of the continental shelf to the point where it cascades over the shelf break until it finds its own density level at a depth of 250 m. The speed of the current is estimated to be in the region of 0.1 ms−1, and at that rate it would have to flow for three months to remove the salt accumulated in the gulf during summer. There is evidence that the flow is unsteady in character, and is possibly released in regular pulses.
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
1. Simpson, J. E. A. Rev. Fluid Mech. 14, 213–234 (1982).
2. Griffiths, R. W. A. Rev. Fluid Mech. 18, 59–89 (1986).
3. Nunes, R. A. & Lennon, G. W. Aust. J. Marine and Freshwater Sci. 37, 39–53 (1986).
4. Nunes, R. A. & Lennon, G. W. J. geophys. Res. (in the press).
5. Bullock, D. A. Trans. R. Soc. S. Aust. 99, 43–57 (1975).
6. Bye, J. A. T. & Whitehead, J. A. Jr Estuarine coastal Mar. Sci. 3, 477–481 (1975).
7. Bowers, D. G. & Lennon, G. W. Continent. Shelf Res. (in the press).
8. Bowden, K. F. Tellus 12, 418–426 (1960).
9. Komar, P. in The Sea Vol 6 (Wiley Interscience, New York, 1977).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lennon, G., Bowers, D., Nunes, R. et al. Gravity currents and the release of salt from an inverse estuary. Nature 327, 695–697 (1987). https://doi.org/10.1038/327695a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/327695a0
This article is cited by
-
Occurrence and seasonal variability of Dense Shelf Water Cascades along Australian continental shelves
Scientific Reports (2020)
-
Capturing expert uncertainty in spatial cumulative impact assessments
Scientific Reports (2018)
-
Mixing, hypersalinity and gradients in Hervey Bay, Australia
Ocean Dynamics (2009)
-
High saline waters in Bay of Bengal
Journal of Earth System Science (1990)
-
Dense water off continents
Nature (1987)
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.