Marine life from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. Microorganisms constitute more than 90% of the marine biomass. A microorganism (or microbe) is a microscopic living organism, which may be single-celled or multicellular. Microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some species of fungi, algae, and certain microscopic animals, such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses (and viroids) as microorganisms, but others consider these as nonliving. In
Leucothrix (bacteria) Leucothrix (bacteria) Leucothrix is a genus of large, filamentous bacteria, which live as epiphytes in marine habitats. "Leucothrix" Oersted, 1844 is the type genus of the family Leucothricaceae Buchanan, 1957, but has also been classified in the family Thiotrichaceae (Gammaproteobacteria). There are two species described, "L. mucor" Oersted, 1844 (type species) and "L. pacifica" Zhang et al., 2015. "Leucothrix" is a large bacterium that forms filaments between 2-3 µm wide and up to 0.5 cm in length. They are usually found as epiphytes on marine plants and algae, but also grow attached to other surfaces like the shells of crustaceans.