Creatures of the Blue Lagoon: Algae, The Atmosphere, and Animals.

Creatures of the black lagoon: Algae, The Atmosphere, & Animals.

It’s widely accepted scientific fact that millions of years ago, ‘life’ heaved itself out of the oceans and on to land, kickstarting this weird and wonderful world and we know (and love?) today. What’s not so clear, is how our prehistoric primordial partners got their act together.

Research published last week in Nature by a research group from the Australian National University, claim they’ve hit the biological jackpot, giving life as we know it an origin story, at last.

The Cryogenian period (approximately 720-635 million years ago) is most famous (amongst very specific circles) for allegedly seeing the largest glaciations across the globe, covering most of the earth’s surface. This is a relative controversial topic amongst geologists, however what really matters, is that during this period, bacteria were thought to be the only living organisms occupying our planet.

A glacier in Iceland

The research team, led by Jochen Brocks, identified trace amounts of fat, the most stable molecular compound over vast time periods. This algal-specific fat is very close to the cholesterol in our own cell walls, and luckily, was well preserved in sedimentary bedrock from the Cryogenian period, found in Australia.

A fresh water algal bloom

What’s so important about algae? Algae are small, photosynthetic microorganisms, occupying both fresh and marine water. They are at the very bottom of the food chain, and therefore be eaten and their energy passed upward to larger organisms. This sudden algal bloom and explosion in marine algal biodiversity at this period, arguably kick started evolution and development of larger and more complex land animals, giving rise to the massive speciatic diversity we see today.

In a quote taken from a BBC interview, Brock claims, “”The signals that we find show that the algal population went up by a factor of a hundred to a thousand and the diversity went right up in one big bang, and never went back again.”

Noah Planavsky, an Assistant Professor at Yale University provides crucial geochemical evidence about phosphate, an inorganic chemical vital for all plant life today. Brock believes that glaciers ground up rocks holding onto phosphate as they moved across the earth, releasing this crucial nutrient into the seas.

A fossilised fern from approximately 500 million years ago

Phosphate and derivatives are crucial to biological life, forming part of the universal energy currency, ATP, which powers every single living cell. It also forms the backbone of our DNA molecules, meaning all this extra phosphate, may well have kicked started the evolution revolution.

Photosynthetic organisms, like these ancient algal species and the complex higher plant life we see today, produce oxygen as a by-product of light-driven energy production. This added increase in atmospheric oxygen levels, driven by this massive algal explosion, may have contributed to increasing oxygen levels, helping higher organisms like us evolve.

You can find the original Nature article by Brocks et al., here.

And the Nature paper by Planavsky describing phosphate deposition, here.


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