Sulphur: This is a vital component in the vast majority of industries and is so important that a country's level of industrialisation is often measured by its sulphur consumption. Most of the sulphur is used in the form of sulphuric acid – this appears in very few of the final products but is usually important to the method of manufacture.
The majority of the sulphur used was laid down hundreds of millions of years ago by ‘sulphate reducing’ bacteria into sulphur ‘domes’. These same bacteria may be associated with oil production as oil is often found near sulphur. Bacteria are not the only source of sulphur, but they are responsible for the most easily accessible (and hence cheapest) supplies.
Natural Gas: This is methane, a burnable gas that produces almost no pollution and which thus has a great potential as a source of energy. It is estimated that methane exists buried in quantities that will far outlast our supplies of coal and oil – about a quarter of this has probably been made by bacteria and the rest is most likely a remnant of the formation of the solar system.
The production of methane by bacteria is relatively rapid and sewerage works can often power all their own equipment with energy to spare, from the methane generated by sewage.
Oil: It is not certain if this is actually made by bacteria, though there is evidence that this is the case. What is certain however is that the action of bacteria causes the oil to collect over shale deposits and make the huge ‘lakes’ that we harvest for our supplies.
Coal: This is directly produced by the action of bacteria. They work by degrading plant matter to form a substance high in carbon and hydrogen, but low in oxygen – this is peat and is a valuable burnable fuel in many less-developed cultures. If this peat becomes buried and is put under pressure then, over vast amounts of time it first turns into ‘brown coal’ and then into the black (bituminous) coal known so well in this country. A layer of peat about one foot thick makes a layer of coal about 1 inch thick. It is not known exactly how peat is turned into coal but it is unlikely that bacteria have anything to do with the process apart from making the peat in the first place.