Microbiomes are an integral part of our planet, existing in every corner of the Earth. While humanity has made remarkable advancements in building cities and infrastructure, the contributions of microorganisms often go unnoticed.

These tiny life forms have evolved over billions of years and encompass a diverse range of entities, including bacteria, archaea, protists, viruses, and fungi. They play crucial roles in our ecosystems, helping to sequester carbon, decompose substances, and supply nutrients essential for the food web.

Moreover, these microorganisms collaborate to support more complex life forms, including humans, with whom they share a long evolutionary history. Though invisible to the naked eye, their presence is vital, as they interact closely with our organs and even help train our immune systems from a young age.

After extensive research into the microbiome, I am eager to share some of the most fascinating insights I have gathered.

#1: Each Person is Surrounded by a Distinct Microbial Cloud

Although it's imperceptible, each individual is enveloped by a unique cloud of microbes, akin to a fingerprint. This microbial cloud may reveal significant information about a person's health, location, and age.

Every breath and scent releases particles and microbes into this cloud. While research on microbial clouds is still emerging, it holds promise for non-invasive health assessments. So, whenever you feel alone, remember that this invisible community of microbes is always with you.

#2: More Bacteria Exist on Earth Than Stars in the Milky Way

This astonishing fact blew my mind the first time I encountered it. Despite the vastness of our galaxy, Earth boasts a staggering number of bacteria—potentially more than a trillion distinct microbial species.

Estimates of bacterial cells on our planet reach an unfathomable total: a nonillion (10^30). To put it simply, that's a one followed by 30 zeros—1,000,000,000,000,000,000,000,000,000,000! In contrast, the Milky Way contains approximately 400 billion stars. Even more astonishing, there are ten times as many viruses on Earth compared to bacteria, making our planet's microbial diversity seem vast compared to the known universe.

#3: Gut Microbes Produce Various Neurotransmitters

The trillions of microbes residing in our gut have remarkable capabilities. Research is revealing that these microorganisms can both create and decompose neurotransmitters, which significantly impact our gut nerves and may also affect the brain.

By breaking down dietary proteins, these microbes influence serotonin metabolism. They utilize biochemical pathways similar to ours to synthesize serotonin, a neurotransmitter that regulates gut function, stress, and mood. Beyond serotonin, gut bacteria are responsible for producing numerous other neurotransmitters and signaling molecules.

#4: Fossilized Excrement Offers Clues to Ancient Diets

Our waste can provide valuable insights into our lives. Our eating habits and physical activity shape our microbiome, and the rise of processed foods and sedentary lifestyles has significantly altered it.

Microbiologists often examine the feces of non-industrialized populations to glimpse the past. When well-preserved samples—known as coprolites—are discovered, they can yield exciting findings. Recently, scientists sequenced coprolites over a millennium old, uncovering numerous novel bacterial genomes. This research suggests that as lifestyles changed, many microbial species were lost from our guts.

#5: Microbes Thrive Deep Within Earth's Crust

Microorganisms exhibit remarkable adaptability to extreme environments. They have been discovered thriving in both Antarctic ice and hot springs, and recent findings revealed bacteria living over 1300 meters beneath the ocean floor.

These microbes endure intense heat and pressure, deriving energy from sulfur and methane in the absence of sunlight. Some even inhabit volcanoes, helping to recycle rare metals and convert methane into fuel. This resilience fuels astrobiologists' hopes of discovering extraterrestrial life, possibly hidden within Mars' crust.

#6: Fecal Transplants Can Combat Antibiotic-Resistant Infections

The concept of fecal transplants may seem bizarre, but they have proven to be life-saving for patients with recurrent, antibiotic-resistant Clostridium difficile infections.

The process involves isolating the microbial community from a donor's stool, although the specific beneficial components remain unclear. These donor microbes can disrupt the existing microbial community in patients, effectively acting as "literal shit disturbers."

#7: Some Viruses Target Bacteria, While Others Target Viruses

In the microscopic world, the relationship between microbes is one of predator and prey. Bacteria need to be wary of bacteriophages, viruses that specifically target them rather than humans or animals.

Bacteriophages are sophisticated entities that inject their genetic material into bacteria, where they can integrate into the host genome or initiate the production of viral proteins, potentially causing the bacteria to burst. Inspired by these viral mechanisms, scientists are exploring bacteriophages as potential treatments for infections, particularly in combating antibiotic resistance.

We are continuously uncovering more about the viruses that inhabit our environment. Some small viruses can hijack larger ones, known as virophages, which may regulate bacteriophages in turn.

Microbes are omnipresent, playing vital roles in maintaining our climate, food systems, and overall health. Each species possesses unique characteristics and functions, and with every passing year, we deepen our understanding of this microbial realm. It’s no wonder scientists are fervently working to harness the potential of these organisms.

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