ARTICLE OF THE DAY

A bog body is a human cadaver that has been naturally mummified within a peat bog. Such bodies, sometimes known as bog people, are both geographically and chronologically widespread, having been dated to between 9000 BCE and the Second World War. The unifying factor of the bog bodies is that they have been found in peat and are partially preserved; however, the actual levels of preservation vary widely from perfectly preserved to mere skeletons.
Unlike most ancient human remains, bog bodies have retained their skin and internal organs due to the unusual conditions of the surrounding area. These conditions include highly acidic water, low temperature, and a lack of oxygen, and combine to preserve but severely tan their skin. While the skin is well-preserved, the bones are generally not, due to the acid in the peat having dissolved the calcium phosphate of bone.
The oldest known bog body is the Koelbjerg Woman from Denmark, who has been dated to 8000 BCE, during the Mesolithic period. The overwhelming majority of bog bodies – including famous examples such as Tollund Man, Grauballe Man and Lindow Man – date to the Iron Age and have been found in Northern European lands, particularly Denmark, Germany, the Netherlands and the United Kingdom. Such Iron Age bog bodies typically illustrate a number of similarities, such as violent deaths and a lack of clothing, leading archaeologists to believe that they were killed and deposited in the bogs as a part of a widespread cultural tradition of human sacrifice or the execution of criminals. The newest bog bodies are those of soldiers killed in the Russian wetlands during the Second World War.
The German scientist Alfred Dieck published a catalog of more than 1,850 bog bodies that he had counted between 1939 and 1986 but most were unverified by documents or archaeological finds; and a 2002 analysis of Dieck's work by German archaeologists concluded that much of his work was fabricated.

Bog Chemistry

The preservation of bog bodies in peat bogs is a natural phenomenon, and not the result of human mummification processes. It is caused by the unique physical and biochemical composition of the bogs. Different types of bogs can affect the mummification process differently: raised bogs best preserve the corpses, whereas fens and transitional bogs tend to preserve the skeleton rather than the soft tissue.
A limited number of bogs have the correct conditions for preservation of mammalian tissue. Most of these are located in colder climes near bodies of salt water. For example, in the area of Denmark where the Haraldskær Woman was recovered, salt air from the North Sea blows across the Jutland wetlands and provides an ideal environment for the growth of peat. As new peat replaces the old peat, the older material underneath rots and releases humic acid, also known as bog acid. The bog acids, with pH levels similar to vinegar, conserve the human bodies in the same way as fruit is preserved by pickling. In addition, peat bogs form in areas lacking drainage and hence are characterized by almost completely anaerobic conditions. This environment, highly acidic and devoid of oxygen, denies the prevalent subsurface aerobic organisms any opportunity to initiate decomposition. Researchers discovered that conservation also required that they place the body in the bog during the winter or early spring when the water temperature is cold—i.e., less than 4 °C (40 °F). This allows bog acids to saturate the tissues before decay can begin. Bacteria are unable to grow rapidly enough for decomposition at temperatures under 4 °C.
The bog chemical environment involves a completely saturated acidic environment, where considerable concentrations of organic acids and aldehydes are present. Layers of sphagnum and peat assist in preserving the cadavers by enveloping the tissue in a cold immobilizing matrix, impeding water circulation and any oxygenation. An additional feature of anaerobic preservation by acidic bogs is the ability to conserve hair, clothing and leather items. Modern experimenters have been able to mimic bog conditions in the laboratory and successfully demonstrate the preservation process, albeit over shorter time frames than the 2,500 years that Haraldskær Woman's body has survived. Most of the bog bodies discovered showed some aspects of decay or else were not properly conserved. When such specimens are exposed to the normal atmosphere, they may begin to decompose rapidly. As a result, many specimens have been effectively destroyed. As of 1979, the number of specimens that have been preserved following discovery was 53.