We’ve seen in Chapter 2 that the corpse of a human is a very rich resource because it offers a large quantity, and wide range, of nutrients to any creature that doesn’t have an aversion to eating dead bodies. However, it’s important to appreciate that the type and quantity of nutrients, as well as the nature of the environment, provided by a corpse change with time. In other words, it’s a dynamic resource rather than a static one. This is due to two main factors. First of all, in most climates the body gradually loses water and dries out. Secondly the activities of microbes, insects and other animals result in the removal of some nutrients but the addition of others, in the form of the waste products of the organisms that are feeding on the corpse. Because of these environmental changes, the types of creature (both microscopic and macroscopic) present on the corpse gradually change – this process is known as “community succession” and is important in many ecological systems. In this chapter we’re going to focus on how microbes make use of the nutrients present in a human corpse. The ways in which insects, the other main group of creatures involved in corpse decomposition, use the nutrients present in human tissues will be described in the next chapter.