What are individual algae cells that are suspended on the surface of the water called?

Planktonic algae refer to individual algae cells that are suspended in the water column, primarily within the upper layers of aquatic environments. These microscopic organisms are free-floating and can be found in various types of water bodies, including lakes, rivers, and oceans. They play a crucial role in aquatic ecosystems as they are primary producers, converting sunlight into energy through photosynthesis and forming the basis of the food web for many aquatic organisms.

Benthic algae, on the other hand, are attached to the substrate at the bottom of water bodies; filamentous algae grow in strings or filaments rather than as individual cells; and rooted algae, while not a standard term, would imply algae that have some form of attachment to a substrate, which does not apply to individual cells that are suspended. Understanding these distinctions helps in the effective management and control of algae in aquatic systems.