* Freshwater algae: These thrive in lakes, ponds, rivers, and streams. They are often a key part of the food chain for fish and other aquatic organisms.
* Saltwater algae: These are found in oceans, seas, and brackish water (a mix of fresh and salt). They are responsible for a significant portion of the world's oxygen production through photosynthesis.
Some types of algae can even live in both environments, demonstrating their adaptability.