The combination of “microscopic” and “grandeur” may seem ironic and antithetical, but the phrase certainly unveils stunning truths; both infinitesimal & monumental. The context to such a phrase is one that is easily dismissed and, unsurprisingly so, human nature permits it- we cannot see it, nor can we hear, smell or feel it. What incentive, then, have we to attend, to observe and to recognise what our senses are unsusceptible to? The easy answer is one that answers all.
The people who thought to look superseded the limits of our senses. Through microscopes we can now see, through knowledge we can now touch and feel, and through metagenomics we can now know. The key discovery of microorganisms: bacteria, fungi, viruses, archaea, protozoa, algae and helminths, to which all life on earth was derived, continues to substantially reform human outlook on life.
Throughout history humans have disproportionally focused on unlocking knowledge from entities and ideas that their senses were capable of processing, but incapable of understanding: the stars, planets, illness and religion among many others. It was not until Anton van Leeuwenhoek, a Dutch cloth merchant, had observed bacteria for the first time that the exponential reality of microorganisms fell into the limelight.
Ever since the discovery of bacteria, and later the other microscopic forms of life, a zeitgeist of then-rational fear and loathing had developed. Germ theory, in which a small subset of microorganisms known as pathogens are known to cause disease, emerged and along with it came a war waged on the very origins of life. Soon, weapons had been designed to eradicate every microbe on every surface of every household, every symbiont on every palm of every human and every miniscule spec of life within our reach in the biosphere. Through antiseptics, antibacterials, antifungals and – more recently – antibiotics, we have cultured (pun intended) a dangerous mindset that licenses the destruction of microscopic life with unbeknownst macroscopic consequences.
The magnificent role of microorganisms in driving life on earth is not to be underestimated, and not easily exaggerated. Photosynthetic bacteria from the Microbiocene, the geological period of time in which the mere presence of microbes had a significant impact (and still do) on the planet and which has now been debatably overtaken by a supposed Anthropocene, produced so much oxygen as a ‘waste’ product of photosynthesis that it has shaped the oxygenated world which now fosters human life. Even in this current age, the marine microbiome generates half of the oxygen in the atmosphere, or in other words: every other breath you take originates from the microscopic life in the oceans.
Among creating conditions required for many life forms to flourish, microbes are planetary forces which nourish the vast majority of the biosphere. Viruses in the ocean, which if you were to lay in a line end to end- would span further than the 60 nearest galaxies, kill 25% of microscopic life (mostly bacteria) in the oceans every day and in doing so are actively recycling energy, carbon and other nutrients bound within the cells by bursting them open and releasing them into the ocean for other aquatic organisms to use. Such a simple concept has considerable implications. One of which that viruses are essentially the premise of ocean productivity- substantially impacting fish populations and hence fishery yields through seemingly altruistic nourishment of fish. Even more impressively, by influencing the carbon flux of the ocean and hence the chemistry of seawater, they are potentially capable of mediating the Earth’s climate by controlling the amount of carbon the ocean absorbs (less carbon absorbed means more heat is trapped in the environment so leading to increased temperatures).
On a human-scale, the human microbiome (communities of trillions of microorganisms colonising external and internal surfaces of the human body) is a “third brain” which operates on a silent yet significant level and is both as chemically complex and functionally vital as the brain. The gut harbours 99% of our human microbiome to form the gut flora which function as metabolisers of food that we cannot digest and therapeutics, bio-synthesisers of essential vitamins and amino acids among a plethora of extraordinary, symbiotic interactions. On the surface of our skin and within our body are microbes protecting us from dangerous pathogens via colonisation resistance- preventing them from occupying space by taking up space and eating the food that pathogens could be living off, they also train and develop our immune system. Research suggests that via the gut-brain axis, bacteria in our gut are capable of communicating with the brain and influencing our behaviour, possibly acting as alleviants of depression and anxiety as well as stimulating food cravings as a strategy for persuading us to feed them with specific food.
In summary, microorganisms, though incredibly small and seemingly non-existent, play a massively critical role in sustaining life on earth. Yes, a minority of them can cause disease, but it is this the obsessive focus on this pessimistic outlook that has distracted us from the incredible life forms that drive ecosystems and prevented us from using our knowledge of these symbionts to our advantage. It is entirely possible that in the near future we could discover a way to manipulate microbes to, say, prevent irritable bowel syndrome or even to target cancers; perhaps we could go so far as to design psychobiotics to cure depression, anxiety and inflammatory disorders. The potential in this is limitless, and I have strong faith that this knowledge is the future of medicine and innovation.
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