A study of the saline lakes of the Esperance Hinterland, Western Australia, with special reference to the roles of acidity and episodicity

Most saline lakes are alkaline, but acid groundwaters in some southern areas in Western Australia cause some to have pHs as low as 3. Their fauna is severely restricted to an endemic brine shrimp (Parartemia sp.), a copepod Calamoecia trilobata, and two species of ostracods, including Australocypris bennetti. Nearby alkaline salt lakes show an attenuating fauna with increasing salinity with dominance by various crustaceans particularly Parartemia spp., various ostracods, copepods, Daphnia (Daphniopsis) truncata, Haloniscus searlei and snails including Coxiella glauerti, as is typical in salinas in southern Australia. When both types of lakes fill with episodic rain, their salinity is vastly reduced and pH approaches neutrality. Such lakes are colonized by insects and by large branchiopods. Many of the latter are new to science and occur only in these brief hyposaline stages. Such a unique assemblage is in danger of extinction due to hypersaline mining waste waters being dumped in saline lakes and to secondary salinization