Algae

Have you ever walked by a pond and touched the rocks at the edge. Sometimes, they feel a little slippery and green. That’s me. Have you ever been to the ocean and seen giant, leafy plants that sway back and forth with the waves like tall dancers. That’s me, too. Sometimes I am so small that I just make the water in a lake look a little cloudy and green, like someone dropped a spoonful of pea soup into it. I can be as big as a tree or so tiny you can’t see me without a special tool. I live all over the world, in salty oceans and freshwater ponds, quietly doing my work. You might have seen me a hundred times without ever knowing my name. Hello there. I am Algae.

I am one of the oldest living things on our planet. My story began a very, very long time ago. My first ancestors, a type of blue-green algae called cyanobacteria, appeared around 3.5 billion years ago, when the world was a very different place. Back then, there wasn't much air for animals to breathe. But I had a secret superpower. I could eat sunlight and burp out a special gas. Starting around 2.4 billion years ago, I worked for millions of years, filling the air with this gas, which you call oxygen. I made the air breathable so that fish, dinosaurs, and eventually people could live here. For a long time, people knew about my bigger forms. The Aztec people, who lived in the 14th century, would gather my cousin, spirulina, from lakes to eat as a healthy food. But my tiniest forms were a secret until a curious man named Antonie van Leeuwenhoek looked at a drop of pond water with his newly made microscope. On October 9th, 1676, he was amazed to see my tiny green shapes swimming and dancing around. He was the first person to see my microscopic world.

Even though I am ancient, I am still a super helper for the world today. You might even find me in your kitchen. I am the dark green seaweed wrapper on a piece of sushi, and I can even be used to make ice cream smooth and creamy. Scientists are also studying me to see if I can be turned into a special fuel to power cars and planes someday. But my most important job has never changed. I am still busy eating sunlight and making the air we all need to live. In fact, all of my family members in the oceans and lakes work together to make about half of all the oxygen on Earth with every single breath you take. So next time you see a green pond or the deep blue ocean, remember me. I am your tiny, powerful friend, and I have been taking care of our planet for a very, very long time.