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
④ The Hidden Alliance Beneath the Soil: A Silent Revolution Led by Root-Dwelling Microbes
⑤ The Invisible Engine of Earth’s Oceans — Why Marine Microbes Hold Our Future
By Jung Yeon-Tae,
President of the Korea Construction Infonet and Essayist
When we look at the ocean, we tend to imagine waves, tides, whales, and fish. Yet the true rulers of the sea are neither large nor visible. They are microscopic organisms that sustain the ocean and help regulate the planet itself. As humanity faces climate change, marine pollution, and the challenge of carbon neutrality, it is crucial to understand this hidden but immense biological network.
The Ocean Belongs to Microbes
Covering 70 percent of Earth’s surface, the ocean is far more than a vast reservoir of water. Trillions of microorganisms inhabit it, and more than half of all marine life is microscopic. Beneath the surface lies a complex symphony of microbial ecosystems. These invisible organisms influence the color of the ocean, shape the formation of sea foam, and generate nearly half of the oxygen we breathe. One out of every two breaths we take originates from the activity of marine microbes.
The Turning Point in Earth’s Atmosphere — The Cyanobacteria Revolution
Around 2.5 billion years ago, Earth’s atmosphere contained almost no oxygen. Then came cyanobacteria, the microscopic pioneers that began producing oxygen through photosynthesis. Their appearance triggered a transformation of the atmosphere, allowing oxygen to accumulate and form the ozone layer. This made it possible for life to leave the ocean and eventually flourish on land. In a sense, every plant, animal, and human today owes its existence to these ancient marine microbes.
Plankton — The Invisible Forest That Produces Half of Earth’s Oxygen
Plankton drifting across the ocean surface may seem insignificant, but more than half of them are microbial. They absorb carbon dioxide and release oxygen, contributing roughly 50 percent of the planet’s oxygen supply. They also play a critical role in stabilizing Earth’s climate. When plankton die and sink to the deep sea, the carbon they contain is stored in the ocean floor. Without this natural carbon burial system, Earth’s climate would be far more unstable than it is today.
Life Thrives Even in the Sunless Deep
Even in the abyss where sunlight never reaches, marine microbes sustain life. At hydrothermal vents on the seafloor, chemosynthetic bacteria use sulfur and iron compounds—not sunlight—to generate energy. These microbes form the foundation of unique deep-sea ecosystems, enabling life in an environment once thought uninhabitable. A whale carcass that sinks to the ocean depths can become a “whale fall,” supporting microbial communities and diverse organisms for decades. Time and again, the deep ocean reveals that life will always find a way.
The Link Between Marine Microbes and Humanity
Marine microbes are not merely components of the natural world; they directly affect human survival and economic progress. Many of today’s promising drug candidates and next-generation biofuels originate from marine microorganisms. Some bacteria even exhibit the ability to break down microplastics, offering hope for reversing human-driven pollution. These organisms are among the oldest life forms on Earth, yet they may also hold the key to solving some of our most urgent environmental crises.
The Ocean Is a Living Organism
The ocean is not simply water and waves. It is a vast biological circulation system powered by microbial life. Marine microbes produce oxygen, lock away carbon, and generate new forms of life. Just as they shaped the early Earth, they may guide the solutions we seek for the future. The ocean is a living organism, and its beating heart is microbial. It is time we listen to this invisible heartbeat, for within it lies the future of humanity.
About the Author
Jung Yeon-Tae is the Director of the Construction Industry Information Institute and an essayist. His writing explores the relationship between science and humanity, bridging nature, the cosmos, and philosophy.
Korean version available here.
