Fact sheet

• Situated east of the small town Cervantes
  Cervantes, Western Australia
  Cervantes is a town in Western Australia. The town is located just off Indian Ocean Drive about north north west of the state capital, Perth in the Shire of Dandaragan Local Government Area. At the 2006 census, Cervantes had a population of 503. The town was named after a ship that was wrecked...
  
  , 2 km inland from the Indian ocean
  Indian Ocean
  The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
  
  .
• Coordinates: 30°30′21.34"S 115°4′42.92"E
• The lake is 300 m wide and ca. 2 m deep.
• The lake is situated on a Quaternary limestone pavement.

Stromatolites, algal mats and fauna in Lake Thetis

The lake is one of only a few places in the world with living marine stromatolites

Stromatolite

Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria ....

. The Lake Thetis stromatolites exhibit unusual columnar branching. These narrow, closely spaced and almost parallel columns are extremely rare in modern stromatolites.

Alongside the stromatolites, a diverse array of benthic microbial communities, such as algal mats, inhabit various layers of the lake. Some of these algal mats are associated with the stromatolites while most confine themselves to a particular area such as the high foreshore areas, splash zone or the central basin of the lake.

The lake water is alkaline and nutrient poor but provides an ideal environment for bottom dwelling microbial communities. The lake contains some small fish, amphiods and a few crustacean species adapted to living in highly saline environments..

Threats

The stromatolite community is threatened by nutrient enrichment and physical crushing. An interim recovery plan is currently being written which will provide direction to further protect this extremely valuable community for future generations.

Recent development

In March 2008, a new entry road and car park, as well as walkways on the shore of the lake were constructed. Additionally, a disused rubbish pit on the northern side of the lake is being rehabilitated and this has eliminated threats associated with rubbish disposal.