Definition: forming a multicellular tubular thallus composed of multinuclear cells that are created when nuclear division is not accompanied by the formation of cell walls
Definition: An aquatic biome that comprises systems of open-ocean and unprotected coastal habitats, characterized by exposure to wave action, tidal fluctuation, and ocean currents as well as systems that largely resemble these. Water in the marine biome is generally within the salinity range of seawater: 30 to 38 ppt.