Plant
Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom. The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the brown, red and green algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, and they are no longer classified as plants as defined here.
Seaweed cultivator
Seaweed cultivators (the devices) are just now becoming available to the public, mainly because of the LED (light-emitting diode) which has made low-cost, reliable, and waterproof illumination sources (especially in the red 660-nanometer spectrum) feasible. Seaweed cultivators are an offshoot of algae scrubbers, which were developed to filter aquariums. By replacing the aquarium with a reservoir of fertilized seawater, a stand-alone cultivator becomes possible, and even a desktop cultivator is possible if the size is small enough or if the reservoir is placed beneath the desk.