Ice algae terrestrial ice algae occur in freshwater systems, the species composition differs greatly from that of sea ice algae. These communities are significant in that they often change the color of glaciers and ice sheets, impacting the reflectivity of the ice itself. Microbial life in sea ice is extremely diverse, and includes abundant algae, bacteria and protozoa. Algae in particular dominate the sympagic environment, with estimates of more than 1000 unicellular eukaryotes found to associate with sea ice in the Arctic. Species composition and diversity vary based on location, ice type, and irradiance. In general, pennate diatoms such as "Nitschia frigida"
Marine life find plant life in the sea, where mangroves or cordgrass or beach grass might grow. Over 1500 species of fungi are known from marine environments. These are parasitic on marine algae or animals, or are saprobes on algae, corals, protozoan cysts, sea grasses, wood and other substrata, and can also be found in sea foam. Spores of many species have special appendages which facilitate attachment to the substratum. A very diverse range of unusual secondary metabolites is produced by marine fungi. Mycoplankton are saprotropic members of the plankton communities of marine and freshwater ecosystems. They are composed of filamentous free-living