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"
Denitrifying bacteria Denitrifying bacteria Denitrifying bacteria are a diverse group of bacteria that encompass many different phyla. This group of bacteria, together with denitrifying fungi and archaea, is capable of performing denitrification as part of the nitrogen cycle. They metabolise nitrogenous compounds using various enzymes, turning nitrogen oxides back to nitrogen gas or nitrous oxide. There is a great diversity in bacteria capable of performing denitrification. Members of this group encompass most bacterial phyla and therefore possess a wide variety of physiological traits. Denitrifying bacteria have been identified in over 50 genera with over 125 different species and are estimated to represent