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"
Mycorrhiza helper bacteria they found that the bacteria helped ectomycorrhizal fungi promote a symbiotic relationship with the plant by examining an increase in formation of mycorrhiza. Some bacteria improve root colonization and plant growth when associated with arbuscular mycorrhiza. The improvement of growth has been hypothesized that MHB aid the plant to defend against pathogens by improving the nutrient uptake. However, the mechanism these species use to help both of the fungi is still unknown and needs to be further investigated. Actinobacteria are gram-positive bacteria, and they are found in the soil. In this phylum, "Streptomyces" is the largest genus of bacteria, and