An account of the techniques using ostracodes in palaeolimnology in Australia

Abstract

Ostracodes are common in Australian waters, especially in saline lakes where they are particularly diverse. This makes them indispensable “tools” for Australian palaeolimnological studies, especially since many Australian lakes are saline. The following types of subjective information can be obtained from the study of Australian fossil ostracode faunas without knowledge of the ecology or taxonomy of their living representatives: the search for a life assemblage can lead to detection of the presence of water currents and the effects of reworking in addition to the identification of particular facies, such as a lake shoreline or a desiccation phase; rate of sedimentation can be estimated as well as the amount of sediment compaction of drying; information on water oxygenation and acidification can be obtained; and, finally, presence of seasonality affecting lakes can be identified. With additional reference to the ecology of particular species, permanency of lake water can be assessed and so can the variability of rainfall and, even at times, the detection of whether a lake was close to a summer/winter rainfall boundary. Shell ornamentation can inform on water depth. In addition, salinity data can be obtained as well as some information on water chemistry and temperature. The latter from trace elements (Mg, Sr) and stable isotope ( δ 18O) studies of ostracode shells.