Monday, February 15, 2016

Stromatolites made life as we now know it

Bob Leis with book and sample of Red Lake stromatolite at camp
Take a deep breath. Does it make you thankful for stromatolites? Well, it should because without them there wouldn't be anything to breathe. Stromatolites are credited for first creating the oxygen that we and almost everything else need for life.
And incredibly, some of the first stromatolites to appear on Earth, a long, long time ago, were right at Bow Narrows Camp at the west end of Red Lake, Ontario!
The entire story is chronicled in a new book: Stomatolites: Ancient, Beautiful and Earth-Altering by Bob Leis and Bruce Stinchcomb with illustrations by Terry McKee.
Bob came to camp last summer to check out the Red Lake stromatolites which at 2.925 billion years old, are among the oldest in the world.
Let's start at the beginning, that is, the beginning of the Earth, 4.6 billion years ago. The brand new planet was nothing like it is today. Geologists call the first 800 million years the Hadean Era. Hadean as in Hades. The Earth's crust was molten, volcanoes everywhere and bombarded by lots of meteors.
The atmosphere was composed of carbon dioxide and methane. Temperatures were extreme and there was no life.
After 800 million years things had cooled down enough that the liquid rock turned solid and was largely covered by water. And right away, at least in geologic terms, life began and started what is called the Archean Era which lasted until 2.5 billion years ago.
The very first life is thought to have been single-celled bacteria that did not need oxygen. But before long, again in geologic terms, cyanobacteria appeared. These were photosynthetic and are the organisms that would eventually create our breathable atmosphere and left the mostly-trace fossils that we call stromatolites.
The cyanobacteria formed dense mats in shallow areas of water. As they continued to grow they calcified and trapped sediments in layers that became stromatolites.
A byproduct of photosynthesis is the production of free oxygen and for the first two billion years that cyanobacteria created free oxygen it was gobbled up by iron molecules to create iron oxides -- hematite and magnetite. This was laid down in layers called Banded Iron Formations. Those formations are what we mine today. So, along with thanking stromatolites for the air we breathe, thank them also for the steel that is the backbone of our modern civilization!
Once all the iron had been bonded with oxygen, the free oxygen went into the atmosphere and this began the Proterozoic Period 2.5 billion years ago to 500 million years ago. Then stromatolites declined because invertebrates and vertebrates evolved and ate them!
Stromatolites are still forming today but they are rare compared to ancient times.
Incidentally, the stromatolites that can be seen on the shores of Red Lake, right in front of Cabin 10  and all the way to Trout Bay, are among the oldest in the Canadian Shield. There is a photo of a sample from camp in the book.
If you have never heard of stromatolites and the role they played in life on Earth it is probably because their existence wasn't totally accepted until about 1960 although they were first discovered in the late 1800s. It just seemed unfathomable that life could have started so quickly, so long ago.
You can buy Stromatolites: Ancient, Beautiful and Earth-Altering at It is published by Schiffer Publishing Ltd.
I got my copy directly from Bob Leis who hails from Northern Wisconsin. He autographed it with "Remember that pond scum rules!"
It is a beautiful book, full of photographs of stromatolites including polished specimens, and diagrams that help explain the whole history. I highly recommend it.
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