Thrombolites of Lake Clifton, Western Australia

 

 

Hi, I am Hilary Wheater. I want to introduce you to an amazing ecological phenomenom, and one of the oldest forms of life on earth, the thrombolites of Lake Clifton, Western Australia

THE THROMBOLITES OF LAKE CLIFTON

Lake Clifton, south of Perth, Western Australia, is the home of the largest reef of living thrombolites in the southern hemisphere.

The thrombolites occur on the eastern shores of the lake stretching over 14 kms from the northern tip of the lake down to Deep-water channel. They are also to be found on the western shore south of Swan Pond.

 

Thrombolites are the homes of tiny microbes. Up to 25 different species of fauna have been identified from within the living rock forms of the thrombolites of Lake Clifton.

Lake Clifton is a salt lake but it is fed fresh water from an underground aquifer. This aquifer lies on a rock bed of limestone. The water of the

aquifer is heavily impregnated with calcium and carbonate ions.

Tiny microbes live in this lake. They don’t float in suspension in the water but they lie in a mat at the bottom of the lake. This mat is called a benthic microbial community.

The fresh water flows up from the aquifer into the lake pushing against the mat of microbes. These tiny microbes appear to have the most amazing ability to attach to the calcium and carbonate ions in the water and to use them to make themselves houses. These microbial houses in Lake Clifton are called thrombolites from the Greek work ‘thrombos’ a clot, because these microbialites are like large clots.

Over 25 different species of microbes were identified from a lump or rock taken from one of the thrombolites.

There are 11 lakes in the Yalgorup Lake System and most of the lakes have extinct microbial reefs. There would appear to be no longer any sign of life in these reefs.

What has caused these reefs to become extinct we do not know. Observation shows that the fresh water seeping up around these lakes is no longer above the reefs, indicating that the water level of the lakes has lowered over time. The microbes and thrombolites might have been left high and dry and just died from lack of water.

An alternative theory is that the lakes may have become more salty as they reduced in depth and that the microbes could no longer tolerate this high rate of salinity.

The only living thrombolites would appear to be on Lake Clifton but their days, too, could be numbered. They are now recognized as a threatened ecological species. A good deal of research is needed to be done on the thrombolites of Lake Clifton and the extinct reefs of the other lakes if the living thrombolites of Lake Clifton are not be lost to us.

For more information on the thrombolites of Lake Clifton, contact FRAGYLE through http://www.fragyle.org.au/ or fragyle@oceanbroadband.net.