This will provide a brief comparison between photosynthesis and chemosynthesis. The point of this is to better illustrate the simalarities between the two processes, often parallels can be seen in such situations. A good knowledge base of one process can lead to a better understanding of the other.
Although not a large amount of research has been initiated on a micro species and ecological basis for these ecosystems, the chemical/metabolic pathways are relatively well understood from other habitats (Thomas et al 1997). A simple form of the reaction that takes place is as follows.
When comparing the equivalent reaction from a photosynthetic organism
The basic equation is the same, multiple single carbon molecules are converted into six carbon carbohydrates. The obvious difference between the two is the energy pathways which make the reaction possible which significantly distinct
In a chemosynthetic process the oxidation of sulphur releases energy in the form of free electrons. The electrons are then passed along a number of transport links (Stewart et al 2005), whereas in a photosynthetic organism pigments (complex protein based molecules) are exposed to light, electrons are then released and transported along a similar chain. In both processes this and other reactions lead to an energy accumulation which results in the formation of the universal energy molecule ATP. Other process and sub-reaction occur as a result of the initial electron release which then leads to further production of ATP. This energy is then used in other metabolic functions but can be used in the synthesis of carbohydrates. In this sense we should then view the simple equations (shown above) as a much larger reaction with lots of mini steps. For the purpose of a brief overview however they demonstrate the routes that organisms take in order to create biological energy in a clear and easily observable manner.