Saturday, 22 August 2026

Cyanobacteria

 

Cyanobacteria

Image courtesy Wikimedia Commons

Anvilcloud pointed out that cyanobacteria (blue-green algae) were crucial in developing Earth’s atmosphere into one which would support human life. I was intrigued by that so investigated. It's straightforward but far from simple.

Cyanobacteria exist anywhere where light and moisture are found, from salty oceans to freshwater lakes, hot deserts and cold soils. In symbiosis with plants and algae they provide nitrogen to their hosts.

Three billion years ago there was little oxygen in the atmosphere. Cyanobacteria in the oceans used energy from the sun to split water molecules and produce oxygen.  During millions of years, the level of oxygen in the atmosphere rose to a point where it could support life. This process is referred to as the Great Oxidation Event and allowed the evolution of animals and eventually human beings.

Cyanobacteria created the ozone layer, a protective barrier against the sun’s harmful ultraviolet rays.

Scientists continue to study cyanobacteria.           

58 comments:

  1. You've got some basic information here which I was not aware of. Awesome post.

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  2. We humans and animals too, owe our entire lives to a bacterium, yet these days everyone, or almost everyone spends a lot of time and money on sanitising everything in their homes. Talk about overkill. I have read of people who thoroughly wash and dry their dishes THEN run them through a dishwasher cycle to "sterilise" them. And the hand sanitiser companies are getting rich....It was bad enough before covid with people afraid of every little germ but I worry now about children not developing a natural immunity system by never being allowed to just go out and play and get a bit grubby.

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    1. I agree with you. Some people are obsessed with keeping all dirt and germs at bay, but 'you have to eat a peck of dirt before you die.'

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    2. Turns out that those who grow up on farms, particularly around cattle (bovines) have least allergies and strongest or most active immune systems. My grandmother opined that we should all eat a peck of dirt before we die.

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  3. Of course, from the viewpoint most of the life that existed at that time, the cyanobacteria were destroying the environment -- poisoning it with oxygen, which they were not adapted to. The majority of the species that existed at the time went extinct. Luckily, since there was nothing more complex than bacteria back then, they didn't "know" what was happening.

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    1. What's good for some is always bad for others . . .

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  4. Fascinating information, thanks

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  5. I wish I'd paid more attention at school . . .

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  6. I do remember learning in science classes that it was one of the earliest forms of life on earth.

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    1. It didn't appear in our science curriculum until 1989.

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  7. I would have thought this was covered in high school biology.

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    1. Only since 1989, so only my grandchildren will have come across it at school.

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  8. Apparently in Australia, we are rather short of Cyanobacteria in our skies.

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    1. I can't find anything about that - sounds worrying . . .

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  9. This is all so interesting

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  10. As usual,your posts are informative. Leave it to humans to destroy the ozone.

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    1. Billions of years to create the ozone layer, hundreds to destroy it - what an achievement!

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  11. I just asked AI if my pool has this bacteria and it said no, pool algae is floating green, this one in you post is black on a pool..

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  12. Really interesting information.

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  13. So I have the Great Oxidation Event to thanks for my existence!!

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  14. Very interesting to explore the beginnings of life

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  15. Very interesting!! Our microbiology professor taught us this at college. It was one of the most interesting subjects for me when I was studying agronomy.

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  16. It is interesting, and multi-layered.

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  17. AC inspires me to think, too.

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    Replies
    1. That's one of the benefits and joys of blogging!

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  18. I always learn something when I read your posts.

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  19. I do remember studying this in school long, long ago and it's good to know it is still a part of the curriculum. It is an important subject and thank you for blogging about it.

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    1. Scientists are still finding new things about it.

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  20. Our earth is a constant source of amazement. One should never stop learning.

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  21. Fascinating read . . . thank you.

    All the best Jan

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  22. You share fascinating studies, very interesting! Thank you and enjoy the rest of your weekend.

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  23. How interesting.. I hadn't even heard of the word.

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    1. I've always just called it blue-green algae.

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  24. I've never been fond of algae of any sort or color but I guess I should temper my feelings some.

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  25. Some bad things are good for us in some forms and vice versa. Knowing which is important!

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  26. Replies
    1. The things we need that we didn't realise we needed!

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  27. I'm learning something new from your blog every time! xxx

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  28. I love the documentaries where they show the fossil record of those bacteria in the layers of iron deposited millions of years ago, in bands because the oxygen released varied by the season. Such a tiny organism and such a big impact.

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  29. A facinating read about this type of bacteria and its importance on the world stage. Take a bow Cyanobacteria.

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  30. Very interesting about the producion of oxygen and the protection of the ozone layer.

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