Algae is a type of aquatic organism that can range from single-celled microorganisms to large seaweeds. Diatoms, SCUM, KELP, SEAWEED, DIATOM, RED, dulse, and PLANKTON are all types of algae. Diatoms are microscopic, single-celled algae with silica shells, while SCUM is a type of green algae that forms a slimy film on the surface of water. KELP is a type of brown algae that grows in underwater forests, and SEAWEED is a type of macroscopic algae that grows in shallow ocean waters. RED algae is a type of algae that is typically found in tropical and subtropical waters, and dulse is a type of RED algae that is edible and often used as a seasoning. PLANKTON is a type of microscopic algae that floats in the water, and seaweeds are a type of macroscopic algae that grows in shallow ocean waters.