Microalgae are, literally, “little seaweeds.” They are living microorganisms that are single-celled or colonial, like bacteria and protozoa. They are different, however, from most other microbes in that they use the energy of sunlight to make their own food by photosynthesis. Microalgae are the primitive ancestors of plants, and microalgae “invented” photosynthesis billions of years ago. Microalgae are enormously diverse, in terms of their physical appearance and internal chemistry. They can be found in the sea, in freshwater, in soil, …