Northern Spencer Gulf Estuary
The estuary in the north of Australia’s Spencer Gulf is classified as an inverse estuary, owing to its unusual pattern of salt distribution and water circulation. In a reverse of the usual pattern, this estuary’s waters become saltier toward its head, away from its mouth. This is because its head is surrounded by hot desert and loses more water to evaporation than enters it from rivers. The head’s high salinity means that it draws in from the mouth ocean water of lower salinity than the water drawn in by a typical estuary. The estuary is surrounded by extensive tidal flats, seagrass banks, and mangroves.