What are algae and why study them?
“Algae” refers to a diverse group of protists (structurally simple eukaryotes = organisms whose cells contain a nucleus and other internal structures surrounded by membranes). Most, but not all, are photosynthetic, producing their own organic material from sunlight, CO2 and mineral nutrients. Algal species range from tiny single cells to the plant-like kelps, which may reach tens of meters in length. Most algae that live in extreme environments are small, often single-celled species. What are often erroneously called “blue-green algae” are actually cyanobacteria, a type of photosynthetic bacteria (see below). Algae and cyanobacteria are important primary producers (base of the food chain) in freshwater and marine ecosystems. They perform an ecological role similar to plants in terrestrial (land) ecosystems. Without algae, there could be little animal life in aquatic habitats. Sometimes algae also become a nuisance, as when your neighborhood pond turns green, or a red tide occurs in the
