Learn about Stromatolites at Hamelin Pool.

Stromatolites feature at Hamelin Pool in the World Heritage area of Shark Bay. Hamelin Pool is also Western Australia’s only marine nature reserve.

The water at Hamelin Bay is twice as saline as usual sea water because of the Faure Sill, a sand bar across the Bay’s entrance, and rapid evaporation from the shallow water. Most living animals, which feed on the bacteria and algae of which stromatolites are composed, cannot tolerate such saline conditions. As a result stromatolites can grow here successfully, undisturbed.

Their presence was a major factor in Shark Bay being declared a World Heritage Area.

Stromatolites at World Heritage Shark Bay

Stromatolites occur elsewhere in Western Australia in the saline Lake Thetis, near Cervantes; in hyper-saline lakes on Rottnest Island; in the freshwater Lake Richmond, at Rockingham; and the brackish Lake Clifton, near Mandurah. The link between all Western Australian microbial structures, regardless of the salinity of the water in which they grow, is the presence of calcium carbonate. The source of the calcium carbonate may be groundwater that has passed through lime-rich substrates.

Microbial mats built from cyanobacteria and other microscopic organisms are the building blocks for stromatolites, the rock-like structures whose origin puzzled geologists for centuries before being found growing in Hamelin Pool in 1954. Before they were known only as fossils. Hamelin Pools stromatolites result from the interaction between microbes, other biological influences and the physical and chemical environment.

Stromatolites are the oldest living organisms on the planet. Some scientists believe they were the first living things on mother earth. Hamelin Pool gives an indication of what the earth may have looked like 3.5 billion years ago when stromatolites were widespread, although the Shark Bay structures are relatively new, being about 3000 years old.

When stromatolites first appeared on earth about 3.5 billion years ago there was little or no oxygen in the atmosphere. It was through the oxygen-generating activity of stromatolites that other animal life on earth was able to develop. Conversely, it is believed that the decline in numbers of stromatolites is related to the evolution of animals that consumed cyanobacteria and algae.

Stromatolites are extremely slow growing. Those in Hamelin Pool grow at a maximum of .3mm a year, so those which are up to a metre high are a few thousand years old.

A wooden boardwalk at Hamelin Pool allows people to view the stromatolites without damaging them. It incorporates informative panels that give visitors a fascinating insight into the formation and lifestyle of the stromatolites and is a good way to find out about the beginnings of life of Earth. (Let “Stumpy” guide you around the boardwalk).

Adventure Tour Itinerary where you will see the stromatolites at Hamelin Pool as part of your tour


Close up of Stromatolites at Hamelin Pool

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Stromatolites Underwater Stromatolites at Hamelin Pool Stromatolites at Shark Bay Stromatolites late in afternoon Stromatolites at World Heritage Area