autotrophers

Autotrophers, commonly referred to as autotrophs, are organisms that synthesize organic matter from inorganic carbon sources. They acquire energy from either light or inorganic chemical reactions and use that energy to fix carbon dioxide or bicarbonate into carbohydrates and other organic compounds. Autotrophers form the base of most ecosystems by providing the primary source of organic matter for other organisms, and they are distinguished from heterotrophs, which rely on preformed organic carbon.

There are two major groups: photoautotrophs, which harvest light energy through photosynthesis, including green plants, algae, and cyanobacteria; and chemoautotrophs, which obtain energy by oxidizing inorganic substrates such as hydrogen sulfide, ammonia, ferrous iron, or molecular hydrogen in environments like deep-sea vents or soil crusts. Most photoautotrophs fix carbon via the Calvin cycle, while some use alternative pathways; chemoautotrophs fix carbon through pathways such as the reverse citric acid cycle or the 3-hydroxypropionate pathway.

Ecologically, autotrophers drive carbon cycling and oxygen production, supporting diverse food webs. They inhabit a wide range of environments, from terrestrial and freshwater to marine ecosystems, including extreme habitats like acidic hot springs and hydrothermal vents.

Evolutionarily, autotrophy has deep roots in the history of life. Oxygenic photoautotrophy by cyanobacteria significantly increased atmospheric oxygen, enabling aerobic respiration and more complex life. Chemoautotrophy is common in nutrient-poor or extreme environments. See also autotrophic metabolism, photosynthesis, chemosynthesis.