<span class="_wysihtml5-temp-placeholder"></span>Aquatic plants grow in shallow to deep water zones. The three main types of aquatic plants are (1) single-celled phytoplankton,
(2) periphyton (algae growing attached to substrates) and (3)
multicellular macrophytes. Phytoplankton includes several groups of
algae (e.g., green algae, golden brown algae, euglenophytes,
dinoflagelates, and diatoms) and one group of photosynthetic bacteria
(Cyanobacteria). Planktonic algae may be either benthic (attached to a
substrate) or planktonic (floating in the water column). There are large
numbers of phytoplankton (> 400 species) in many bodies of freshwater; phytoplankton are most common in habitats with high nutrient levels.