After it was determined that cyanobacteria, a phylum of prokaryotic organisms often referred to as blue-green algae, is not actually a type of algae, its classification was moved to the Bacteria domain. Even though cyanobacteria are photosynthetic and aquatic, the only relation that the group has to algae is the chloroplast. However, the name "blue-green algae" is often used when discussing aquatic organisms capable of making their own food.
As studies of the protists progressed, it was determined that they should not necessarily all be lumped into one kingdom, and thus the protists became loosely grouped under Eukarya. Some types of algae are considered protists, including those that are Chromista (a eukaryotic supergroup that is sometimes considered its own kingdom), while others continue to be considered plants (including the Chlorophyta) by certain scientists. Many algae are loosely grouped by color: green, red, and brown