The alveolates are a major clade of unicellular eukaryotes of both autotrophic and heterotrophic members. Chemotrophs can be either autotrophic or heterotrophic. It can easily adapt between heterotrophic and autotrophic lifestyles. Such organisms are not defined as autotrophic, but rather as heterotrophic. Some sources divide the heterokonts into the autotrophic Ochrophyta and heterotrophic Bigyra and Pseudofungi. Heterotrophic microorganisms are important in oxidising carbon (decomposition) whereas autotrophic microorganisms are important in nitrification. They exploit the autotrophic, heterotrophic or mixotrophic properties of "C. vulgaris". Nitrification is an aerobic process performed by small groups of autotrophic bacteria and archaea. This pathway is also used for carbon fixation by autotrophic sulfate-reducing bacteria and hydrogenotrophic methanogens. Cyanobacteria are an important autotrophic bacteria in the water food web. These are primitive multicellular, autotrophic, shade loving, amphibious plants. Algal mats consist largely of filaments made of autotrophic bacteria and fine-grained particles. Primary production occurs in autotrophic organisms of an ecosystem. Increased turbidity of surface waters causes biological oxygen demand and more autotrophic organisms die. "Thermoproteus" is a genus of anaerobes that grow in the wild by autotrophic sulfur reduction.