A family of Gram-negative bacteria in which the cells are variously shaped, and may or may not bear flagella. They are characterized by their ability to obtain energy from the oxidation of either ammonia or nitrite (according to species), and typically they use carbon dioxide as their sole source of carbon. Growth can occur only in the presence of air. There are several genera, found in soil, and in freshwater and marine environments.
Subjects: Plant Sciences and Forestry.