[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
③ The Revolution Beneath Our Feet — The Invisible Life That Keeps Plants Alive
By Jung Yeon-Tae,
President of the Korea Construction Infonet and Essayist
The Hidden Forest Underground
When we walk through a forest, we only see half of it. The other half lies hidden beneath the soil — a silent world where plant roots intertwine with countless microorganisms. This underground ecosystem forms an invisible forest, a vast network of life. Surrounding every root are microbes working in partnership with plants. They are not mere cohabitants but finely tuned allies, shaped by evolution. Through an intricate exchange of nutrients and signals, they sustain one another. The underground world is quiet, yet it operates by the principle of cooperation and symbiosis.
The Nitrogen Factory in Roots — The Secret of Rhizobium
If you pull up a legume plant, you’ll notice tiny round nodules on its roots. Inside these nodules live Rhizobium bacteria, nature’s nitrogen factories. They convert atmospheric nitrogen into ammonium, a form plants can absorb. In return, plants provide sugars produced through photosynthesis. This partnership allows soybeans, peas, and peanuts to grow even in poor soil. What’s remarkable is that Rhizobium doesn’t pair with just any plant. Roots release chemical messengers called flavonoids, and Rhizobium responds by sending back a molecule known as the nod factor. Only when this exchange of signals succeeds does symbiosis begin. Their encounter is as delicate as two lovers recognizing each other’s language.
Trees and Fungi — The Mycorrhizal Alliance
Forest trees also join hands with fungi. The fungi attach to root tips and spread fine threads, or hyphae, through the soil. This partnership is called mycorrhiza, a Greek term meaning “fungus-root.” Through their vast network, fungi absorb water and minerals such as phosphorus, iron, and magnesium, while trees share their photosynthetic sugars in return. About 90 percent of all plant species on Earth depend on mycorrhizal symbiosis. This alliance forms the foundation of the forest’s self-sustaining cycle. Even more astonishing, these fungal networks connect multiple trees underground, creating a vast web of communication. Through this network, trees share nutrients and even send aid to sick or shaded neighbors. The forest, therefore, is not a collection of individual trees but a single living organism woven together by microbes.
Chemical Conversations — The Language of Life
Roots are not mere organs of absorption. They speak a chemical language. Through the secretion of amino acids, organic acids, and sugars, plants send messages to microbes: “This is a safe place; let’s live together.” In response, beneficial microorganisms gather around the roots, forming protective barriers against pathogens and supplying essential nutrients. Studies show that plants engaged in active symbiosis exhibit greater resilience to climate change and disease. Symbiosis is not a survival tactic but an ancient wisdom nature has refined for hundreds of millions of years.
The Revolution Beneath Our Feet — A Message for Humanity
No plant on Earth grows alone. Beneath every root lies a world of microbes. Rhizobium provides nitrogen, fungi deliver water and minerals, and bacteria guard against disease. Without this invisible web of cooperation, neither agriculture nor civilization would exist. We often say humans cultivate plants, but in truth, it is microorganisms that cultivate life — sustaining plants, and through them, us.
If the microbes in the soil disappear, human civilization will vanish with them.
This is no exaggeration. Thanks to this quiet revolution beneath our feet, the Earth continues to sustain its green breath of life.
About the Author
Jung Yeon-Tae is the President of the Korea Construction Infonet and an essayist. His writing explores the relationship between science and humanity, bridging nature, the cosmos, and philosophy.
Korean version available here.
