Lake Eyre
When Lake Eyre is full, the water is almost fresh and native fresh water fish can live in it. The lake becomes saltier as the  salt crust dissolves over six months. This kills millions of fish. When about 4m deep the Lake is as salty as the sea. It becomes more salty as the water evaporates. At about 500mm depth the Lake becomes a "pink" color because of a beta-carotene pigment made by the algae Dunaliella salina.