In Jenolan’s depth

 

You should wonder – with amazement

What is it you stare;

Cyanobacteria, twenty thousand years old, they say

But why should anyone care?

More beyond drab rocks in limestone tomb,

Precious life hides in this stony layer?

 

The first ones who had learned to breathe,

Stromatolites a complex name,

But these were the ones who gave out air

For the burning world to tame

This is then a pilgrimage – one to the farthest past

To Life, its primal shrine

Last reminders left - how the mortals were woken up

When the earth was turned divine…

 

The sonnet is dedicated to the Nettle Caves in the wider Jenolan Caves network where one can see cyanobacteria in the stromatolite rocks. Stromatolites (meaning layered rocks) are living fossils and the oldest living lifeforms on our planet. They are stony structures built by colonies of microscopic photosynthesising organisms called cyanobacteria. As sediment layered in shallow water, bacteria grew over it, binding the sedimentary particles and building layer upon millimetre layer until the layers became mounds. Their empire-building brought with it their most important role in Earth’s history. They breathed. Using the sun to harness energy, they produced and built up the oxygen content of the Earth’s atmosphere to about 20%, giving the kiss of life to all that was to evolve.
Their significance lies in the fact that they help us witness how the world looked at the dawn of time – 3.5 billion years ago. Living stromatolites are found in only a few salty lagoons or bays on Earth such as in Western Australia. The cyanobacteria found in Jenolan caves are also similar.  Given the Earth and the Solar System is estimated 4.5 billion years old, it’s staggering to realise how ancient and primal is this life form nonetheless helping us be awed and overwhelmed to witness how the world looked at the dawn of time even before the continents were forming. Before plants. Before dinosaurs. Before humans. If the gods descended on earth, this then would have been their first avatar.

 

Information on Stromatolites from BBC