The ecosystem of one of South Australia’s iconic waterways, the Coorong, is on the verge of collapse as lack of freshwater pushes salinity to deadly levels, according to Flinders University researcher, Dr Simon Benger.
Dr Benger says the impacts of climate change are compounding more than a century of mismanagement of Murray Darling Basin water resources and, without a major injection of water, the outlook for the Coorong and the Lower Lakes of Alexandrina and Albert is bleak.
“Collapsing ecological systems, acid-sulphate soils, declining water quality, loss of livelihoods, shrinking lakes and the demise of local communities are but a few of the many problems impacting the Coorong and Lower Lakes region,” Dr Benger, from the School of Geography, Population and Environmental Management, said.
“Researchers in our cluster have documented accelerated species loss throughout the Coorong, with many species of fish, aquatic vegetation and macroinvertebrates disappearing completely from the system or now restricted to smaller areas near the Murray Mouth,” he said.
Dr Benger said rising salinity levels in the lakes – up to four times accepted maximum levels for Adelaide drinking water – were thought to be behind emerging problems such as the spread of polychaete worms which build large calcareous mounds wherever colonies become established.
“Larger creatures such as crabs and turtles are being overwhelmed by the weight of worm formations on their shells and are dying in large numbers,” he said.
Dr Benger said his component of the Flinders research, supported by the CSIRO Water for a Healthy Country Flagship under the Coorong Lower Lakes and Murray Mouth (CLLAMM) ecology program, was recording the physical habitats of the Coorong and developing dynamic Geographical Information Systems (GIS) based models of how the area might respond to changes in water level and water quality.
“If fresh water should once again become available from the Lower Lakes and the Upper South East Drainage Scheme in significant volumes, we will be able to predict how the system might respond,” he said.