Where is the energy coming from?

              Chemoautotrophic bacteria utilize sulfur-containing inorganic compounds as an oxidizing substrate (Gage and Tyler 1990) .  Organic carbon is derived from carbon dioxide and methane  directly from the vent. Sulfate reduction provides energy for many bacteria.  Additionally, heat from the vents themselves drive chemical energy (see figure below) .  The creation of organic molecules, similar to the chemoautotrophic bacteria, occurs in the endosybionts of the macrofauna (Gage and Tyler 1990).