Hydrogen sulfide chemosynthesis is a form of

chemosynthesis In biochemistry, chemosynthesis is the biological conversion of one or more carbon-containing molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic compounds (e.g., hydrogen gas, hydrog ...

which uses hydrogen sulfide. It is common in hydrothermal vent microbial communities Due to the lack of light in these environments this is predominant over

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...

Giant tube worm ''Riftia pachyptila'', commonly known as the giant tube worm and less commonly known as the Giant beardworm, is a marine invertebrate in the phylum Annelida (formerly grouped in phylum Pogonophora and Vestimentifera) related to tube worm ...

s use bacteria in their

trophosome A trophosome is a highly vascularised organ found in some animals that houses symbiotic bacteria that provide food for their host. Trophosomes are located in the coelomic cavity in the vestimentiferan tube worms (Siboglinidae, e.g. the giant tube wo ...

to fix carbon dioxide (using hydrogen sulfide as their energy source) and produce sugars and

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

s. Some reactions produce sulfur: : hydrogen sulfide chemosynthesis: :: 18H₂S + 6CO₂ + 3O₂ → C₆H₁₂O₆ (

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or m ...

) + 12H₂O + 18S In the above process, hydrogen sulfide serves as a source of electrons for the reaction. Instead of releasing

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

gas while fixing carbon dioxide as in

, hydrogen sulfide chemosynthesis produces solid globules of sulfur in the process. Mechanism of Action In deep sea environments, different organisms have been observed to have the ability to oxidize reduced compounds such as hydrogen sulfide. Oxidation is the loss of electrons in a chemical reaction. Most chemosynthetic bacteria form symbiotic associations with other small eukaryotes The electrons that are released from hydrogen sulfide will provide the energy to sustain a proton gradient across the bacterial cytoplasmic membrane. This movement of protons will eventually result in the production of adenosine triphosphate. The amount of energy derived from the process is also dependent on the type of final electron acceptor. Other Examples Of Chemosynthetic Organisms (using H₂S as electron donor) Across the world, researchers have observed different organisms in various locations capable of carrying out the process. Yang and colleagues in 2011 surveyed five Yellowstone thermal springs of varying depths and observed that the distribution of chemosynthetic microbes coincided with temperature as ''Sulfurihydrogenibiom'' was found at higher temperatures while ''Thiovirga'' inhabited cooler waters Miyazaki et.al., in 2020 also found an endosymbiont capable of hydrogen sulfide chemosynthesis which contained campylobacter species and a gastropod from the genus ''Alviniconcha'' oxidise hydogen sulfide in the Indian Ocean Furthermore, chemosynthetic bacteria such as purple sulfur bacteria have yellow globules of sulfur visible in their cytoplasm.

References

{{Reflist Biochemistry Metabolism Organisms living on hydrothermal vents Ecosystems Environmental microbiology Biological processes