Lake Thetis Thrombolites

Lake Thetis is a small inland saline lake 1.25km from the Indian Ocean and 1.7km south-east of Cervantes. It is estimated that the lake became isolated from the sea about 4,800 years ago when
sea levels dropped and coastal dunes formed around the lake.

The lake is one of only a few places in the world with living marine stromatolites, or ‘living fossils’. The microbes that build stromatolites are a species of cyanobacteria and are similar to those found in 3,500 million-year-old rocks. The lake’s stromatolites that look like rocky lumps have been dated to about 3,370 years old.

Stromatolite communities grow as the thin layer of bacteria on their surface deposit calcium, cementing sediment into bulbous structures.

The lake contains some small fish, amphipods and a few crustacean species
adapted to living in highly saline environments. The circumference of the lake is 1.5km and provides an interesting and enjoyable walk. Please stay on the path and boardwalk provided.