Endangered living rocks

We walk lightly on the short path that leads us to the boardwalk on the edge of Lake Clifton. The branches of Melaleuca (paperbark) trees that arch across the path shelter us from the morning sun.

We inspect the peppering of shiny black spots that float around us on our walk. These Jewel (Christmas) spiders have spun their large orbed webs across the path, netting small flying insects.

As the Melaleucas and their resident golden whistlers, blue wrens and spiders recede behind us in our approach to the boardwalk, a vast expanse of glassy water opens before us.

Spread across the landscape like an elongated blue iris gazing up to the sky, the lake glows in the light of the ancient sun. The gentle, warm breeze feels like the lake breathing in and out, in and out.

The lake is the mother which cradles the most striking feature to new visitors of Lake Clifton; the thrombolites. Standing on the wooden boardwalk, we look towards these rock-like domes that form a limestone coloured reef that stretches into the distance along the shallow eastern edge of the lake.

This alien landscape is an encounter with deep (geological) time.

While the Lake Clifton thrombolites are estimated to be 2000 years old, thrombolites have existed for over 3.5 billion years. The reef of thrombolites at Lake Clifton takes our imaginations to when they covered vast swathes of the earth’s surface. 

Despite their lifeless appearance, these ‘living rocks’ are formed from the incessant activity of microbial communities. This made them pivotal to the evolution of life on earth billions of years ago because the photosynthesis of the cyanobacteria of the thrombolites filled the earth’s atmosphere with oxygen.

While having survived multiple planetary extinction events, there are only a few surviving thrombolite colonies on the planet. The thrombolites at Lake Clifton are endangered by increased salinity, decreased rainfall, decreased lake water levels, land clearing and pollutants from surrounding areas (Smith, Goater, Reichwaldt, Knott & Ghadouani, 2010).

Our walk among the thrombolites reminds us of the entanglement of life and loss with time’s passing. 


Smith, M., Goater, S., Recichwaldt, E., Knott, B. & Ghadouani, A. (2010). Effects of recent increases in salinity and nutrient concentrations on the microbialite community of Lake Clifton (Western Australia): are the thrombolites at risk? Hydrobiologia, 649, 207-216.