Thursday, June 27, 2019


I've often spoken with students about the excitement of present giving holidays like birthdays and all the rest. They invariably tell me about the newest brightest shiniest new thing that has taken their fancy.

The discussion comes suddenly to a screeching halt when I explain that my most favourite gift was a very old, brownish stonelike object totally absent of any whistles and bells and no electronic diet. The hush over the students is sheer disbelief .

When I then begin to explain that they owe their lives to this little stone-like thing I present before them, you can see on their faces they are quite sure that I have gone completely around the twist and I have their attention!
Microsopic image from UC Berkeley article here

For these are images of a stromatolite. Stromatolites are the constructs that currently 'house' the very first life to create energy from water and sunlight called cyanobacteria.

Cyanobacteria sweetened the poisonous atmosphere of earth during the Archaean and Proterozoic Eras by generating the oxygen that we depend on. This change was important in shaping the course of earth's history through evolution and ecological change.

There are only two places major places in the world where you can see living stromatolites. One place is the Hamelin Pools in Western Australia. The Hamelin Pool is the most extensive living stromatolite system in the world and they live in water that is twice as salty as normal seawater. It is so salty that seasnails that might fancy a nice meal of cyanobacteria can't survive.

Seagrass meadows form a buffer or barrier between the the Hamelin Pool and the rest of the ocean and prevent dilution of the super salty water. However the seagrass is under threat from pollution and human traffic. 

The Hamelin Pool is a protected area.and visitors have restricted access by boardwalk. 

 Photo by Jason Bartsch...See more here  

Since those life changing days so much has happened and ocean phytoplankton now provide more than half of the air we need to breathe. 

There were no bells and whistles with stromatolites but these mushroom-like rocky mounds are the legacy of our ocean and atmosphere heroes, the cyanobacteria. Without them todays plants and animals, that we need to exist, wouldn't be here and neither would we.

Australia, what an amazing ocean continent.

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