The impact of regulation and salinisation on floodplain lakes: the lower River Murray,Australia |
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Authors: | Peter Gell John Tibby Fiona Little David Baldwin Gary Hancock |
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Institution: | (1) Geographical & Environmental Studies, University of Adelaide, Adelaide, 5005, Australia;(2) Geology and Geophysics, University of Adelaide, Adelaide, SA, 5005, Australia;(3) CSIRO Land & Water, Black Mountain, ACT, 2601, Australia |
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Abstract: | Floodplain lakes along the lower River Murray are subject to a wide range of human impacts including regulation, abstraction,
elevated saline groundwater tables, increased nutrient and sediment fluxes and introduced biota. These perturbations are superimposed
on those arising from high inter-annual rainfall variability, driven, at least in part, by variations in the southern oscillation.
Sediment-based archives from two lakes within a complex of wetlands, situated near to the first site of irrigation development
in the lower River Murray, reveal substantial changes over the last 800 years. While high levels of salinity are not foreign
to the sites, the recent trend is towards sustained high salinity levels. As a result of European impact, freshwater diatom
plankton now dominates Loch Luna, whilst Loveday Wetland is both more saline and nutrient rich than in the pre-European period.
In Loveday Wetland, the post-1960 increase in Haslea spicula (Hickie) Lange-Bertalot, may be driven by increases in sulphur salt concentrations that are believed to be a cause of recent
acidification episodes. A recent increase in more salt tolerant diatoms in Loch Luna suggests that this site, which has been
largely buffered from substantial change, is becoming more vulnerable to perturbation.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. |
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Keywords: | Diatoms Floodplain lakes Salinisation River regulation Palaeolimnology |
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