This bacterial phylum comprises highly diverse organisms with a wide range of metabolic pathways, such as sulfur-releasing photosynthetic pathways, nitrate respiration, or the use of methane as a food source, among many others. Some bacteria in this group utilize hydrogen sulfide from thermal waters that are at temperatures of over 100 degrees in the abyssal depths, and transform it into sulfuric acid, thus obtaining energy to live. This sustains the only ecosystem with animals that does not depend on sunlight. Most pathogenic bacteria, such as those causing salmonellosis, typhoid fever, plague, or cholera, are found in this group, along with many other bacteria living inside organisms, such as our intestine, which are necessary for animal life.