The Ocean in Your Lungs: Why Plankton Matter

What are plankton and why should we care?

As you read this, you’re breathing in the ocean. Not literally—unless you’re reading this underwater with some impressive gear. But with every breath you take, half the oxygen in your lungs was created by tiny organisms floating in the waters around us.

These beings, collectively called phytoplankton, are invisible to the naked eye, yet they quietly keep us and all breathing life alive. The word “plankton” comes from the Greek word for wanderer or drifter, and that describes their lifestyle perfectly. They drift through the world’s waters in numbers so vast they’re almost incomprehensible. All known species of these microalgae placed end to end would stretch from Earth to the Moon, forming a 400,000-kilometre chain of life.

Their diversity is astonishing. Take phytoplankton, the plant-like members of this vast family. Even within this group, the variety is immense. Diatoms, for example, build intricate glass-like shells around themselves, tiny structures that have inspired designs in architecture and engineering. Dinoflagellates propel themselves through water using whip-like tails called flagella. Some species can even produce their own light through bioluminescence, creating the magical blue glow sometimes seen in ocean waves at night.

Diatom Asterionella, approx. 40 µm. North Sea, Germany. Photo: Anthea Oestreicher.

Houses of glass. Diatom Coscinodiscus, approx. 200 µm. Baltic Sea, Germany. Photo: Anthea Oestreicher.

Dinoflagellate Stareso Photo: Anthea Oestreicher.

How the Ocean Learned to Breathe

To understand their importance, we need to go back in time—about three billion years. The Earth’s early atmosphere was a cocktail of carbon dioxide, nitrogen, ammonia, and methane. It was nothing like the air we breathe today. In this alien world, some cyanobacteria made one evolutionary leap and invented photosynthesis.

This new ability allowed them to transform sunlight, water, and carbon dioxide into energy and oxygen. We know this chemical reaction from school biology classes, but at the time it was revolutionary. These single-celled organisms didn’t just survive in the early oceans; they transformed the planet. They released oxygen into the atmosphere and eventually created the conditions for complex life to evolve.

They still do this today. Phytoplankton continue to photosynthesise and produce about half of the oxygen on Earth—roughly as much (if not more) as all land plants combined. Every second breath you take is thanks to phytoplankton.

Diver Portrait. Giglio. Italien. Photo: Unknown.

The Blooming Sea

Are all of them truly invisible? Not entirely. NASA scientists use the term “breathing Earth” (A Breathing Planet, Off Balance – NASA, 2015) to describe how the planet’s gas exchange creates visible rhythms from space. In satellite images from springtime, the ocean blooms with turquoise and green. These vast clouds of phytoplankton are photosynthesis in action, happening on a planetary scale. These blooms appear seasonally, when conditions for growth are just right. As the seasons shift, storms stir the water layers, nutrients rise from the deep, and the cycle continues.

NASA didn’t invent the idea of a breathing planet. Many Indigenous cultures have long recognised these planetary rhythms. The Rarámuri call it iwigara (Enrique Salmón, 2020), a concept describing the interconnectedness of breath and life. The Cree, Salish St’át’imc, and Yup’ik also describe land and sky as living, breathing systems (Siragusa et al., 2020). Modern science is only beginning to catch up with what many cultures have always known: our planet breathes, and we are part of the rhythm. But we now know phytoplankton is the basis of all that.

Wikimedia Commons: Scala dei Turchi

The Plankton Afterlife

What about carbon? Phytoplankton continue to matter even after they die. The cliffs of Dover, the Scala dei Turchi in Italy, and the chalk cliffs on Rügen are all made from the remains of ancient plankton.

Coccolithophores, another type of phytoplankton, surround themselves with tiny chalk plates. When they die, these plates sink down to the seafloor, slowly forming limestone. Over millions of years, these sediments are pushed upwards, becoming the bright white cliffs that mark coastlines. These ancient deposits are also quarried and used to build cities and monuments. And still, there is more.

Their afterlife doesn’t end with stone. When they die and sink, coccolithophores carry carbon with them to the ocean floor, removing it from the atmosphere and trapping it in the deep ocean. In doing so, they help regulate the climate. Thanks to plankton, the ocean absorbs nearly a third of all carbon dioxide emissions.

Plankton net tow in choppy waters off the coast of Lerici, Italy. Photo: Raphael Berr. Credit: Anthea Oestreicher.

A Breathing Planet

Why does this matter to us—now? This ancient system is clearly under threat. Climate change is warming and acidifying the ocean. That makes it harder for phytoplankton to build their protective structures and disrupts the delicate cycles they’ve maintained for billions of years. All of us are struggling to adapt to the rapid changes we’ve set in motion.

Understanding plankton isn’t just about appreciating nature’s magic. It’s about seeing ourselves differently. These microscopic wonders connect us to ancient evolutionary processes, ocean rhythms, and the daily work of planetary maintenance. They show us that the systems we live within are alive, dynamic, and fragile.

How can we shift our perspective? How can we see that the air we breathe, the climate we live in, and the stones beneath our feet carry the signature of these tiny structures? Their flexibility is part of what makes them so successful. They’ve found ways to thrive in every environment—oceans, rivers, lakes, and ponds. From the tropical surface to the rich depths of polar seas, they have adapted to more habitats than almost any other organism on Earth.

But perhaps the most remarkable thing is how they make the invisible visible, if we just know how to look. They reveal that we live within a breathing planet, connected to cycles and rhythms far older and larger than human civilisation. With them, we can begin to understand ourselves—not as separate from nature, but as part of an ancient community of life, sharing the same breath, the same water, and the same story of survival on a small blue planet.

Want to Learn More?

If you’re curious to dive deeper, join us for the next TechBrunch on Saturday, 10 August 2025 at HEK. Together with Anthea Oestreicher, we’ll look at water samples, explore the world of plankton under the microscope, and reflect on the delicate systems that connect us to more-than-human life. The workshop takes place as part of the finissage weekend of the exhibition Other Intelligences. More information can be found here.

In the meantime, here are a few links Anthea has shared for further exploration:

Video installation by Anthea Oestereicher
Recently featured on the YAS Emerging Artist Platform
(Soon also available on Anthea’s YouTube channel)

NASA – A Breathing Planet, Off Balance
Satellite footage showing seasonal phytoplankton bloom cycles:
Watch on YouTube

David Attenborough on Phytoplankton
A short segment on the power of these tiny organisms:
Watch on YouTube

We look forward to seeing you at HEK!