From Big Medical Encyclopedia

AUTOTROPHIC ORGANISMS (grech, autos + trophe food) — the organisms capable to independently synthesize organic matters from inorganic.

K A. islands belong the higher hlorofillsoderzhashchy green plants and the lowest photosynthesizing — sulfur bacteria (purple, red, green), seaweed and chemosynthetic bacteriums (nitrifying, gray, iron bacteria, etc.).

Green plants synthesize organic compounds from carbon dioxide and water, using energy of light quanta (see. Photosynthesis , Assimilation , at plants). In the course of photosynthesis these substances turn into elementary organic molecules of glucose of which are under construction then more complicated molecules. Purple, red and green sulfur bacteria (Thiorhodaceae, Chlorobium) at photosynthesis, unlike green plants, use as a source of the hydrogen going for recovery of carbonic acid, not water, but hydrogen sulfide.

Chemosynthetic bacteriums carry out synthesis of organic matters, using the energy which is formed at oxidation of certain mineral connections. E.g., the colourless sulfur bacteria of Beggiatoa live in the warm sources containing hydrogen sulfide which it oxidizes before formation of free sulfur. At exhaustion of reserves of hydrogen sulfide of the environment she uses the sulfur which is saved up in her body, oxidizing the last to sulfuric to - you. Soil nitrifying bacteriums (Nitrosomonas and Nitrobacter) oxidize in the enzymatic way ammonia to salts nitrogenous and nitric to - you and use the energy which is marked out at the same time. A part of energy (6 — 7%) goes for recovery of carbonic acid and synthesis of organic matter. Nitrifying bacteriums play an important role in a nitrogen cycle (see), turning ammonia into nitrates, easily available to green plants. Iron bacteria (Leptothrix ochracea, Spirophyllum infurcatum, etc.) develop in the water containing ions of protoxidic iron, a cut they oxidize to oxide.

Value A. the lake for wildlife is huge. Only they create organic matter, a cut are not capable to synthesize other live organisms.

Bibliography: Vernadsky V. I. Chosen compositions, t. 5, page 63, M., 1960.

E. I. Barabanov.