Life Begins

    There was an article in the London Review of Books simply titled, "All Hail the Microbe," a subject that went hand in hand with the book I was finishing, a book by author Ruth Kassinger titled Slime.  Yuck, who would think that was interesting?  But then, as with so many stereotypes we've grown up with, I became fascinated with the study of microscopic life and how difficult life is to just survive at that level, much less to evolve (but life is easy to end as this Covid-19 virus is now teaching us).  Okay, backing up a bit, here was how I basically viewed our early evolutionary beginnings: our cosmic start was fiery with a harsh atmosphere and little water but slowly bacteria emerged and evolved into multi-celled organisms that self-reproduced, then RNA and DNA and, well, throw in a few billions of years and out popped us...humans.  Author Mark O'Connell tried to explain it simply but with a bit more detail and wrote this about what he terms, the Great Oxygenation Event  ...which had happened about two and half billion years ago, a mass extinction from which all subsequent life on Earth had evolved.  Back then, the world was populated exclusively by single-cell organisms, which lived beneath the surface of oceans that were bloodred due to the massive levels of iron in the water.  These microbes relied exclusively on anaerobic methods of respiration -- until one species, the cyanobacteria or blue-green algae, began to use the Sun's light to generate vastly more energy than its anaerobic colleagues, by which method it thrived and increased its numbers exponentially, creating via the disruptive innovation of photosynthesis an exploding surplus of oxygen in the planet's atmosphere, toxic to almost every other living thing on Earth.  This one rogue microbe changed the atmospheric constitution of the Earth, causing the obliteration of most existing life on the planet and preparing the way for the evolution of multicellular organisms such as ourselves.

Photo of algal growth: Sciworthy.com

    But of course, there was much, much more to the actual story.  As Slime author Kassinger pointed out, in those early beginnings we would not have recognized our planet since it was spinning twice as fast (the sun would rise and set every six hours), the moon was ten times closer and the water was there, in fact our oceans were double their size.   And this is where the story actually begins (admittedly, it's a bit wordy but just try and take it in...this is you, after all, or how you actually came to be give or take a few billions of years): The world's oceans have twice as much water as they do today, but the water is disappearing molecule by molecule.  Because there is no oxygen in the atmosphere, there is no ozone layer.  Without an ozone layer, ultraviolet radiation from the sun pours down on the planet unimpeded and blasts water into its components of hydrogen and oxygen.  The lightweight hydrogen atoms go speeding off into space, and the oxygen immediately bonds with minerals in the water.  Without an ozone layer, Earth is heading toward arid lifelessness, a fate that is befalling watery Venus, which is now bone-dry.  Nonetheless, at this time, there are oceans on our planet, oceans that harbor simple, single-celled bacteria and their single-celled cousins, the archaea.  Like all living beings, these microscopic creatures need energy to function, as well as to construct more cell components when they are ready to divide to reproduce.  Because their cell walls are rigid, eating their fellow creatures for energy is impossible.  They can, however, pull compounds like hydrogen sulfide through their cell walls and into their interiors, where the compounds chemically react to release electrons.  They use the electrons to create a short-term store of energy in a molecule called ATP (adenosine triphosphate).  Then, using the energy of ATP and carbon dioxide dissolved in the water, the organisms build the organic compounds, including amino acids, proteins, lipids, and carbohydrates, that they need to live and reproduce...

   Her decription goes on from there, but basically it comes down the this, some of those beginning organisms changed color and floated near the surface to capture the sun's protons to make energy (photosynthesis), then developed a method to make nitrogen (necessary for life and previously only able to be accomplished with power of a lightning strike; without this key development life would never have moved beyond the simplest of ocean creatures) AND work to keep some of its oxygen (which was almost immediately bonding with iron in the waters, so much so that 85 billion tons of iron ore were created or an amount equal to 5% of our entire planet's crust).  The evolving organisms began changing into different shapes, each with different functions, but first it had to block the harmful UV radiation from the sunlight since there was no ozone layer...a mucus layer of slime (polysaccharides) did the trick, the trademark signature of algae: ...with time measured in hundreds of millions of years, the first cynobacteria multiplied beyond all imagination.  Along the way, they evolved into species with a multitude of sizes and shapes: balls and ovoids, rods and spirals and filaments. (The smallest and most prolific, the round Prochlorococcus, was only discovered in 1986; there can be as many as four hundred thousand of them in a single teaspoon of ocean water).  With no predators, they multiplied and absorbed carbon dioxide and released oxygen which finally used up all of its binding molecules in the water and then headed to land to rust the rock and only THEN, did oxygen begin to make its way into our atmosphere.  But the new oxygenated atmosphere was toxic to existing life which began dying and releasing methane gas in the process which turned into carbon dioxide and water.  No big deal, you say?  This massive shift in life by cyanobacteria was slowly cooling our fiery planet.  Soon Earth became a giant snowball covered in ice and snow.  As author Kassinger put it: Microscopic algae, innocuous in the singular and extraordinarily powerful in the unfathomable many, had first conquered and then killed a living planet.  But it's difficult to keep a planet with a hot core covered in ice...

   Okay, too much gibberish about chemicals and biology and all that other scientific-sounding blah-blah-blah; but fast forward past microalgae and multi-cellular and shape-shifting organisms that had to adapt to harsh conditions: "thrive in hot water (up to 56 degrees Celcius or 132 degrees Fahrenheit), and tolerate sulfuric acid, arsenic, and other heavy metals."  But this is where lichen enters the picture, some 15,000 versions of them; had they not arrived we wouldn't have any soil or plants with roots (it's complicated, but fascinating).  Said Kessinger about lichen: Even though we humans contain ten times more bacterial cells than we do human cells, we're still Homo sapiens.  Not so with a fungus that takes up with an alga (lichen): both parties' identities vanish in the merger, and once formed, they can never be separated.  Algae alone has 72,000 distinct species (at least, so far, since the author adds that there may be ten times as much waiting to be named).  There is no shortage of algae.  The oceans are blanketed in a dense but invisible six-hundred-foot thick layer of them.  There are more algae in the oceans that there are stars in all the galaxies in the universe.  Swallow a single drop of seawater, and you could easily down several thousand of these unseen beings.  They are the essential food of the microscopic grazing animals at the bottom of the marine food chain.  If all algae died tomorrow, then all familiar aquatic life --from tiny krill to whales-- would quickly starve...Take a breath: At least 50 percent of the oxygen you inhale is made by algae.  What is waste to them is priceless to all respiring animals.  Without algae, we would gasp for air.

   To peer inward into the small, into the beginnings, is something that takes us ever deeper into an increasingly complicated world.  Scientists are only now delving into the microbiome of our bodies, said National Geographic: Every one of us has a particular mix of microbes that's different from everyone else's...These microorganisms (we have trillions) can communicate with our brains to regulate bodily functions and even influence our mood, as well as chronic conditions such as anxiety, through chemical communication pathways known as the gut-brain axis.  That's not all, said The Conversation: Microbes are the truly dominant group of lifeforms.  These invisible pieces of biogenic matter have been running Earth’s affairs for billions of years.  Plants and animals popped up as the by-products of microbial mergers relatively recently in our planet’s history.  Understanding microbes is not easy.  It took us some time to learn about the existence of the human microbiome, the collection of viruses, bacteria and fungi inside and outside our bodies that connects us to the rest of the microbial cloud that exists everywhere life can survive.  We are now learning that there is even a microbiome high in the sky.  These are microbes that are swept into and then reside in the lower parts of the atmosphere.  This includes the mid and upper troposphere at altitudes of between 8km and 12km above the ground, and the lower stratosphere at altitudes of up to 15km.  What’s more, by joining the planetary wind systems, these lifeforms create microbial highways in the sky that transport them across the world.   Scientists first reported  the existence of sky-bound bacteria in a couple of pioneering studies published in 2013 and 2018.  These were not isolated microorganisms found by chance.  Instead, bacterial communities straddle the sky in large numbers, in the region of hundreds of thousands of bacteria for each cubic metre of air in the troposphere.  Need a bit more convincing of the number and the importance of this populated microbial world...A study from the University of Rhode Island reported that scientists had successfully revived ancient bacteria from deep on the ocean floor, as in 100 MILLION-year old bacteria.

    Author Lavinia Greenlaw writes in the microbe article mentioned earlier: We now move more sediment each year than all the world’s rivers combined and the demand for sand is only exceeded by that for water.  But this is also the way things pile up: the implications, the endless connections, the long life of our destructive tendencies.  There is the impulse to claim and build, to drill and extract, to take up more space.  There is also the desire to see, grasp, know, understand, to go where no one else has been, higher and deeper and to the heart of the matter...The past leads us to the future by reminding us that our perceptual framework is ours alone and will not sustain.  We are obviously still learning, even as we feel that we have attained a superiority of sorts.  But peek at even the smallest of fish and you may be able to spot the lateral line that runs along the side, a thin line called a neuromast, a "sensor" that reads water motion and pressure that allows, said National Geographic: ...fish to identify movement very precisely -- helping them hunt prey, avoid obstacles, and swim in schools, even in the dark.  

   This virus has made me hark back to an early novella by Arthur C. Clarke, Childhood's End.  Like this virus, humanity is caught off-guard.  Missiles fired at the alien ships don't explode but simply disappear; poverty, violence, hunger and abuse are all ended but still the humans in charge try to "defeat" this invader...so the aliens simply wait, two generations they say, enough time to let the "old school" of thought, the existing mindset of biases and prejudices, die out.  Children, those who have grown up knowing only the peaceful alien crafts, emerge with a new way of thinking (for one, they learn to get their energy not from food but, like algae, from the sun, thus becoming photoautotrophs and not heterotrophs...ha, another science lesson!).  This virus is forcing us to accept more than a bit of humility.  We are seemingly only now discovering that there is a world of microscopic organisms that actually run not only our world, but us.  They have survived not millions of years, but hundreds of millions of years.  We have been on earth, at least in a "civilized" form, for about 6,000 years.  Still, as World Atlas wrote: Homo sapiens is the most advanced of all living species on the planet.  There are about 7.5 billion people on the planet and researchers anticipate that the evolution of the Homo sapien can only be rendered extinct by a planetary-level catastrophe.  

    That may be true in our eyes, eyes still filled with that old school of thought.  But while we may feel quite in control and quite the proud and popular species, consider this from Jeff Goodell's book about out melting glaciers and ice-capped poles, The Water Will Come: Antarctica is about seven times bigger than Greenland and contains much more ice.  If the whole continent were to melt (a scenario that would likely take thousands of years), it would raise the Earth's sea levels by about two hundred feet.  If all of Greenland were to go (a scenario that could take significantly less time), it would raise sea levels about twenty-two feet.  To put the volume of water we're talking about here into perspective, if all seven billion human beings on the planet suddenly jumped into the ocean, it would raise sea levels about one hundredth of an inch.