An invisible world supports our planet. In this installment, the author explores the intricate order and symbiosis of microorganisms in soil to reveal where the cycle of life begins.
[Series Lineup]
① Earth, The Planet of Microbes — History of the Invisible Masters
② Another Universe Beneath the Soil — The Living Forces That Sustain the Earth
By Jung Yeon-Tae,
President of the Korea Construction Infonet and Essayist
The World Beneath Us: A Universe in a Gram of Soil
The soil we tread on is far more than a lump of dirt. Under a microscope, scientists discover a complex web of life as vast and intricate as another universe. A single gram of soil contains more than one billion microorganisms—bacteria, actinomycetes, fungi, protozoa, and viruses—all intertwined in cycles of consumption and renewal. These biochemical interactions make it possible for plants to grow and for humans to harvest food. The ground beneath our feet is, in truth, a massive factory of life.
The Allies Beneath the Roots
Inside the root nodules of leguminous plants live nitrogen-fixing bacteria (Rhizobium), which convert nitrogen from the air into forms that plants can use. Long before humans invented chemical fertilizers, these bacteria sustained the planet’s nitrogen cycle.
Forest trees also form alliances underground. Their roots host mycorrhizal fungi, which absorb water and minerals in exchange for sugars produced through photosynthesis. This delicate partnership functions like a conversation between life forms.
In the forest, even when one tree falls ill, others may send nutrients through the underground fungal network to support it. This invisible communication system has been called “the Internet of the Earth.” The world beneath the soil operates not on competition but on the principle of cooperation.
The Scent of Soil: A Gift from Actinomycetes
The familiar earthy aroma that rises after rain comes from a compound called geosmin, produced by actinobacteria. Geosmin serves as a signal of microbial reproduction—an announcement to animals that “life has awakened after the rain.” Its scent is proof that the Earth still breathes.
Actinobacteria also transformed human medicine. In 1943, American scientist Selman Waksman discovered the antibiotic streptomycin from soil actinomycetes. Since then, many life-saving antibiotics have originated from these soil microorganisms. The medicines that cured humanity were not gifts from the heavens but from the living organisms beneath our feet.
Soil Is Alive
Soil is not a heap of dead minerals. Within it, countless organisms perceive one another, compete, and cooperate to form a perfect cycle of life. This system is more efficient than any human-made city—there is no waste, and every byproduct becomes food for another form of life. Even death is not decay but a transformation into a new beginning.
“To return to the soil” is not merely a metaphor. We literally rejoin the microbial world, continuing the endless cycle of rebirth. That cycle is the fundamental law of life on Earth.
Where the Cycle of Life Begins
Humans look to the stars and imagine the universe, but the true cosmos lies beneath our feet. Soil microorganisms nurture plants, purify air, and sustain human life. They are the Earth’s hidden heart and the origin of all biological cycles.
Our task now is to understand their language and protect this living soil. If the soil dies, humanity cannot survive. The civilization that dreams of space ultimately stands upon a handful of living earth.
About the Author
Jung Yeon-tae is the director of the Construction Industry Information Institute, an essayist, and science-philosophy columnist. He is the author of The Management of Destiny, The Star Story Series, and Philosophy of Generative Positivity. His writings explore the interrelationship between nature, the universe, life, and humanity.
Korean version available here.
