A smorgasbord of chemical reactions

A SMORGASBORD OF CHEMICAL REACTIONS—Microbes living in the subsurface at or near deep-sea hydrothermal vent sites exploit a wide range of conditions. Here is a list of known or possible chemical reactions microbes use to live and grow.

➀ Aerobic metal and metal sulfide oxidation(Fe+2 or Mn+2 + O2 Fe+3 or Mn+3 + H2O)
➁ Aerobic sulfide/sulfur oxidation (H2S + O2 H2SO4)
➂ Aerobic methane oxidation (CH4 + O2 CO2 + H2O)
➃ Aerobic hydrogen oxidation(H2 + O2 2H2O)
➄ Anaerobic sulfate reduction(5H2 + SO4H2S + 4H2O)
➅ Anaerobic iron reduction(Fe+3 + H2Fe+2)
➆ Sulfur reduction via organic carbon utilization(Organic C + elemental SH2S + CO2)
➇ Anaerobic sulfur respiration(Elemental S + H2H2S)
➈ Anaerobic methane production (methanogenesis)(4H2 + CO2CH4 + H2O)

(Illustration by Jayne Doucette, © Woods Hole Oceanographic Institution)