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Scientist Erica Suosaari examines Stromatolites Photo: Annette Ruzicka
Scientist Erica Suosaari examines Stromatolites Photo: Annette Ruzicka


Hamelin Pool is home to the most extensive living Stromatolite system in the world.

The Stromatolites of Hamelin Pool at Hamelin Station Reserve may look like a cross between gigantic cauliflowers and rocks, but they're incredibly important as modern examples of the earliest known life forms on Earth.

Stromatolites – Greek for ‘layered rock’ – are microbial reefs created by cyanobacteria (formerly known as blue-green algae).

The Stromatolites of Hamelin Pool at sunset. Photo Jason Bartsch.

Stromatolite deposits are formed by sediment trapping and binding, and/or by precipitation activities of the microbial communities (Awramik 1976). The microbes are active on the surface layer of the Stromatolites, while the underlying build-up is a lithified remnant of former microbial surface communities, that could be interpreted as a trace-fossil.

These deposits built up very slowly: a single 1m structure may be 2,000 to 3,000 years old. But the tiny microbes that make up modern Stromatolites are similar to organism that existed 3.5 billion years ago!

Close up of Stromatolites at Hamelin Pool. Photo Marie Lochman / Lochman Transparencies.

For context, consider that the Earth itself has been around for 4.5 billion years, and that Homo sapiens have only been on Earth for 195,000 years.(1)

What’s more, Stromatolites are the reason why we’re alive today! Before cyanobacteria the air was only 1% oxygen. Then, for 2 billion years, photosynthesising Stromatolites pumped oxygen into the oceans (like underwater trees, before trees existed). When the oceans’ waters were saturated, oxygen was released into the air, and with around 20% of oxygen in the air, life was able to flourish and evolve.(2)

Even today you can see Stromatolites ‘fizzing’ underwater, releasing oxygen.


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Where do Stromatolites live?

Living Stromatolites are no longer widely distributed. There are only two well-developed marine Stromatolite areas in the world: in the Bahamas and at Hamelin Pool in the Shark Bay area of Western Australia.

Hamelin Pool is home to the most extensive living Stromatolite system in the world: the organisms thrive in the area’s hypersaline water, which is twice as salty as normal seawater.

Australia’s marine Stromatolites are protected: they're part of the Hamelin Pool Marine Nature Reserve, which lies within the UNESCO World Heritage listed Shark Bay. The adjacent Hamelin Station Reserve is now owned by Bush Heritage Australia.

A group gathers to discuss Stromatolites at Hamelin boardwalk. Photo Ben Parkhurst.

Threats to Stromatolites

Hamelin Pool is perfect for Stromatolites because it’s hypersaline. Sea grass forms a ‘barrier’ between Hamelin Pool and the rest of the ocean, preventing ocean circulation, which would dilute the super-salty water.(3)

But sea grass meadows are being damaged by the runoff caused by floods and extreme temperature events.Climate change is likely to lead to more frequent tropical storms and more frequent flooding events in the area,(4) threatening the Stromatolites of Hamelin Pool.

Human interference is another threat. To protect the delicate structures, visitors are restricted to the boardwalk. From here they may be underwhelmed: Stromatolites look a little like cow pats from that vista. But, as Stromatolite expert Dr. Erica Suosaari says:

“Underwater, the shapes, the sizes and the different mat surfaces are overwhelming in their variety…you feel like you’re in you in a Precambrian world!”

What’s Bush Heritage doing?

On the border of Hamelin Pool lies Hamelin Station, a 202,000 hectare property that we purchased in 2015. Hamelin Station was once a pastoral property running sheep and goats. We’ve since removed stock and have begun a process of restoration and revegetation. These land management practices will help to lessen the damage of runoff events in the future.

Donate today to help us continue this and other vital conservation work.

Stromatolite stories

BLOG 12/12/2017

A dusty window to the ancient past

Dust - it can be the bane of life in the bush, getting into everything, damaging equipment, making work around the house and shed. But it turns out we can learn a lot from dust about the Earth's history. Every grain has a unique chemical signature that provides information both about its origin and about the chemistry of the environment in which it accumulates.

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BLOG 26/05/2017

Geological field trip to Shark Bay

We were thrilled to again host the annual Curtin University Shark Bay field trip at Hamelin. Over the past 20 years Applied Geology Students have made the trek to Shark Bay to examine geology of the southern Carnarvon Basin.

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BLOG 11/04/2017

Cambrian Stromatolites of Texas

I recently had the chance to travel to an ancient Cambrian Stromatolite system in Mason, Texas with a group from Rice University and the University of Miami. These Upper Cambrian (~500 million-year-old) carbonates contain fossil Stromatolites that can be broadly compared to the modern system in Hamelin Pool.

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BLOG 22/11/2016

BRUVS in Hamelin Pool

Renowned for its natural beauty and scientific significance, the Shark Bay World Heritage Area is home to the Wooramel Bank, which is the largest seagrass bank (4,800km2) in the world. It also has one of the largest and most stable populations of Dugongs, and the largest and most diverse assemblage of modern Stromatolites in Hamelin Pool.

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BUSHTRACKS 16/06/2016

Hamelin Pool: the key to our past

Over billions of years, a complex interaction between climate and environment at Hamelin Pool has created the miracle of ‘living fossils’ called stromatolites. These extraordinary natural monuments contain microbes similar to those found in 3,500-million-year-old fossils – the earliest record of life on Earth.

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BLOG 28/04/2016

Curtin University at Hamelin Station

Hamelin Pool is indeed one of the most phenomenal places on the planet. I recently had the pleasure of being able to share some of my favourite localities with students from Curtin University. For me it was an incredible experience to be able to share my knowledge of Hamelin Pool with a group of keen, smart students who were keen to learn and thoroughly enjoyed the wonder of the region.

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BLOG 15/04/2016

Stromatolite research in Hamelin Pool

Hamelin Pool is home to the most extensive and diverse actively accreting Stromatolite development in the world – a better understanding of the modern Stromatolites in Hamelin Pool may help offer understanding to life on early Earth.

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