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 Another study found that MHB release antifungal metabolites into the soil. The anti-fungal metabolites produce antagonistic effects towards the pathogenic fungi. However, MHB can choose whether to help defend a pathogen depending on the nutrient availability and space in the rhizosphere. Further research is still necessary to understand the mechanism of how MHBs aid mycorrhiza defeat pathogens. Mycorrhiza helper bacteria Mycorrhiza helper bacteria (MHB) are a group of organisms that form symbiotic associations with both ectomycorrhiza and arbuscular mycorrhiza. MHBs are diverse and belong to different bacterial phyla including both gram-negative and gram-positive bacteria. Some of the most common types