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"
John Lightfoot (biologist) "Ryssus", but including also "Lichen" as "Algae Terrestres", terrestrial algae. Only nine genera of fungi are recognised in the book: "Agaricus", "Boletus", "Hydnum", "Phallus", "Helvella", "Peziza", "Clavaria", "Lycoperdon", and "Mucor" (listed on page 645); a tenth fungal genus, "Tremella" is covered, but included among his algae. "Scottish Fungi" note that "While his classification might be a bit wonky by today's understanding, most of the species he recorded can be traced to modern taxa", and that he provided the first British records for the chanterelle and the summer truffle. The book has an "English and Scotch Index of the Names of