Hydrobiologia

, Volume 591, Issue 1, pp 117–134

Palaeolimnological evidence for the independent evolution of neighbouring terminal lakes, the Murray Darling Basin, Australia

Authors

    • Geographical & Environmental StudiesThe University of Adelaide
  • Peter Gell
    • Geographical & Environmental StudiesThe University of Adelaide
  • Deborah Haynes
    • School of Earth & Environmental ScienceThe University of Adelaide
  • John Tibby
    • Geographical & Environmental StudiesThe University of Adelaide
  • Gary Hancock
    • CSIRO Land Water
Salt Lakes

DOI: 10.1007/s10750-007-0799-y

Cite this article as:
Fluin, J., Gell, P., Haynes, D. et al. Hydrobiologia (2007) 591: 117. doi:10.1007/s10750-007-0799-y

Abstract

The estuary of the lower River Murray features a complex mosaic of lakes, coastal lagoons and interconnecting channels. The waters of these wetlands are degraded as a result of river regulation, water abstraction, salinisation, sedimentation and the recent constriction of the River mouth. Palaeolimnologial analysis of sediment cores in two wetlands reveals that salinity in the large terminal Lake Alexandrina was only moderately influenced by tidal inflow, particularly over the past ca. 2000 years. It is now largely fresh as a result of isolation by a series of barriers completed by 1940 AD. In contrast, the seaward portion of the Coorong, a back barrier coastal lagoon, was determined to be a subsaline estuary strongly influenced by marine inflows. These findings contrast somewhat with the Coorong’s current Ramsar classification as a saline lagoon. Riverine diatoms, typical of the fossil flora of Lake Alexandrina, are rare or absent in the Holocene sediments of the Coorong, other than for a short period in the late Holocene in the northernmost end of the lagoon. The palaeolimnological evidence for independent evolution of these wetlands is consistent with geomorphic evidence of a stranded, last interglacial shoreline that acted as a sill limiting the exchange of flows between Lake Alexandrina and the Coorong lagoon.

Keywords

River regulation Estuaries Diatoms Salinisation Sedimentation Eutrophication Ramsar

Copyright information

© Springer Science+Business Media B.V. 2007