The more the environment departs from the ideal, the slower growth becomes until it eventually ceases altogether. If the environment becomes hostile enough, death occurs. In considering whether conditions are conducive to attack it should be noted that the environment in question is not the original undisturbed site but that prevailing after construction has been completed and the structure is in use. For example, excavation and back- filling markedly increase microbial activity in soil as a result of aeration and mixing of different layers. Temperature Bacteria, especially in the endospore form, are very resistant to temperature extremes.
Fungi behave like bacteria but are less resistant to high temperatures.
Adult insects are killed by both high and low temperatures, but survival in cold weather is ensured through the egg or larval form if the adults do not build a colony that is protected from low temperatures. It is not always appreciated that insects, through the heat given off in respiration. The increase in temperature leads to greater activity so that there is an accelerating effect. Oxygen Bacteria are the only organisms that do not necessarily require oxygen. Some need it to survive, some do not need it but can survive in it, and others are killed by oxygen.