Ulothrix
Ulothrix is found in both marine and freshwater environments, especially nutrient-rich freshwater lakes and streams. The genus is free-living, can form mats, or is attached to rocks, wood, damp soils, or other substrates. Ulothrix is more abundant in colder waters.   The growth of Ulothrix zonata is well documented in the cool waters of Lake Superior. This species is also found in smaller northern lakes in the spring and fall but is noticeable absent in the summer.
When the water temperatures rise above 10° C, the filaments degrade and produce zoospores. Ulothrix zonata is closely related to marine species, and researchers believe that over time it left marine habitats to adapt to freshwaters. In China, the species Ulothrix flacca is a significant food source.