Description:
Ostracods are microscopic, aquatic Crustacea with calcareous carapaces and are common components of estuarine ecosystems. The valves of ostracods are commonly preserved in sediment and thus can be very useful for reconstruction of palaeoenvironmental conditions. Utilising a combination of assemblage composition, ecophenotypy, taphonomy and shell chemistry (stable isotope and trace element), a great deal can be determined about estuarine formation and evolution, such as past salinity, water temperature, hydrochemistry, substrate characteristics and nutrient availability. Here, I provide an overview of how ostracods can be utilised in palaeo-studies of estuaries with examples that include hydrodynamic change, sea-level and climate variability, and the impact of pollution.