Phytoplankton

I float and drift in the warm, sunny parts of the water. You can't see me, but I am everywhere in the oceans, lakes, and rivers. I am a plant, but I don’t have roots or stems or leaves. In fact, I'm so tiny that millions of me can fit in a single drop of water. Can you imagine that?. Like the trees in a forest, I soak up the sun's golden light and breathe in the carbon dioxide you breathe out, and in return, I give you fresh oxygen to breathe. You might be surprised to learn that my family and I make about half of all the air on Earth. I am also the main course for tiny creatures like krill, which then become a tasty meal for fish, penguins, and even the biggest blue whales. When my relatives and I get together for a giant sun-feast, we bloom in huge, beautiful swirls of green and blue. We paint the oceans with colors so big they can be seen all the way from outer space. I am the planet's invisible garden, the breathing forest of the sea. I am Phytoplankton.

For billions of years, I lived my life completely unseen by people. It’s true. My ancient ancestors, a type of me called cyanobacteria, started puffing out oxygen around 2.4 billion years ago. They completely changed the sky, filling the air with the oxygen that all the animals that would one day live on Earth would need to breathe. But even though my family was doing this incredibly important job, nobody knew I was there. Then, in the 1670s, a very curious man in the Netherlands named Antonie van Leeuwenhoek built one of the world's first powerful microscopes. He decided to look at a single drop of pond water, and he was amazed. He saw a busy, bustling world of tiny swimming creatures he called 'animalcules.' He was one of the very first people to ever lay eyes on me. It was like he had discovered a secret universe hidden in plain sight. For hundreds of years after that, scientists kept studying me under their microscopes. In 1887, a German scientist named Victor Hensen finally gave my family its official name. He called us 'plankton,' from a word that means 'drifter,' because we wander wherever the ocean currents take us. He was the one who realized we weren't just tiny specks; we were the grassy fields of the sea, the very first and most important link in the ocean's enormous food web.

Even with powerful microscopes, people could only see a tiny part of my story. They could see me and my cousins wiggling in a drop of water, but they couldn't see my massive family spread across the entire globe. They didn't understand how I traveled on ocean currents or how my colorful blooms could affect weather patterns and sea life thousands of miles away. That all changed when humans learned to look down at their planet from above. In the late 20th century, they began sending special cameras called satellites into space to look back at Earth. One very important one for me was launched on August 1st, 1997. It was called SeaWiFS, and its special cameras could see my green color—my chlorophyll—all the way from hundreds of miles up in space. For the very first time, people saw my true size and power. They watched my beautiful, swirling blooms drift across the oceans, some of them bigger than entire countries. They could see where my family was thriving and where we were struggling. Looking from space helped scientists finally understand that I am a huge, breathing part of the whole planet, connecting the ocean, the air, and the climate in one big, beautiful system.

Today, you know just how important a tiny drifter like me can be. Every second breath you take comes from me and my relatives in the sea. I am the base of the food web that feeds so many of the ocean animals you love, from the smallest shrimp to the mightiest whale. By absorbing carbon dioxide to grow, I also help keep our planet's climate from getting too warm, acting like a giant air conditioner for the Earth. Even though I am small, my family is mighty, and together we are proof that even the tiniest beings can have a huge and wonderful impact on the world. So the next time you look out at the vast, sparkling ocean or take a deep, fresh breath of air, I hope you'll think of me, your tiny, invisible friend who works day and night to keep our beautiful blue planet healthy and alive for everyone.