Casper's Law: air speeds decay eightfold compared with burial
A rough rule of thumb called Casper's Law captures how much surroundings matter. All else being equal, remains left in open air break down twice as fast as those under water and eight times faster than those buried in soil. The difference comes down to temperature, moisture and, above all, how easily insects can reach them.
Decomposition turns dead organic material back into simple ingredients such as water, carbon dioxide, mineral salts and simple sugars. It is a core part of the nutrient cycle, recycling the finite matter the living world depends on. Scientists distinguish abiotic breakdown, driven by chemistry or physics, from biodegradation carried out by living things. Bacteria and fungi do most of the work, helped by earthworms and other soil animals, and the field that studies the process is called taphonomy, from the Greek taphos, tomb.
Breakdown begins at once through two routes. In autolysis, the body's own enzymes start dismantling cells once oxygen supply stops and acidity rises. In putrefaction, bacteria already living inside multiply and consume tissue. Researchers describe animal decomposition in five broad stages running from fresh to dry remains, and the community of microbes shifts in predictable ways as it goes.
Surprisingly, decay leaves a lasting mark on the landscape. The ground around a carcass becomes what researchers call a cadaver decomposition island. At first vegetation there dies back, but the soil gains carbon, phosphorus, potassium, calcium, magnesium and a large boost of nitrogen. Later, plant growth surges, a sign that nutrient levels are still out of balance, and full recovery can take several years.
Conditions can stop the process almost entirely. Warmth speeds microbial work and cold slows it; a body needs some moisture to decompose, yet too much creates oxygen-poor conditions that slow things again. In extremely dry or frozen settings, remains may become mummies. Frozen ones such as Otzi the Iceman can resume decaying when thawed, while heat-dried mummies stay preserved unless moisture returns. In cool, damp soil or under water, fats can turn into a waxy substance called adipocere, which suppresses the responsible bacteria and further slows the process.
Source: Decomposition
