Algae

ocean · plants · photosynthesis · water

Tiny to enormous. Algae come in all sizes. Some are so small you need a microscope to see them, but others, like giant kelp seaweed, can grow up to 160 feet long, about as tall as a 16-story building.

Make their own food. Algae are like underwater plants that use sunlight to turn water and air into food and oxygen. They're some of nature's best at this trick, which is why oceans stay so healthy.

Live in water. Most algae float freely in rivers, lakes, and oceans as plankton, drifting wherever the water carries them. Some bigger algae have special hooks called holdfasts that stick them to rocks like underwater anchors.

Work together sometimes. Many algae stick together and form colonies, working as a team. Single-celled algae called Spirogyra form long, sparkly spiral chains that drift through freshwater.

Feed the world. Algae are super important because they produce oxygen and food for billions of fish and ocean animals. Without algae, most life in the ocean couldn't survive.