Decomposition of Pigs Help Understand "Floaters"
'Floaters' May Decompose in Deep Water Much Faster Than Previously Believed
April 7, 2016 / Seth Augenstein / forensicmag.com
Floaters – bodies found in water – are generally thought to be better preserved, due to slower decomposition rates. But new research on pig carcasses indicates that deeper, more oxygen-rich water can significantly speed up breakdown processes, according to a study in PLOS One. Criminologists at Simon Fraser University on the western coast of Canada tested decomposition on pig bodies deep in the Strait of Georgia, a body of water separating Vancouver Island from mainland British Columbia. Previous studies done by the school had been performed at 100 meters and seven to 15 meters in other bodies of water near Vancouver. But the latest pigs 300 meters deep in the Strait of Georgia showed that evidence could disappear much faster, from the natural processes of the dead, according to Gail Anderson, one of the authors.
"However we've found that in highly oxygenated deeper water, it can be expected that such a body would be skeletonized in less than four days, although bones could be recovered for six months or more,"
"Earlier studies… indicate that a (pig) carcass approximating a human body in torso size, skin type and internal bacteria would be likely to survive for week or months, depending on oxygen levels, season, depth and whether it remained in contact with the seabed," said Anderson. "However we've found that in highly oxygenated deeper water, it can be expected that such a body would be skeletonized in less than four days, although bones could be recovered for six months or more," she added. The decomposition was constantly monitored by video camera, and sensors recorded temperature, salinity, turbidity and other environmental factors. "Floaters" have some general rules for death investigations, according to the textbook Practical Homicide Investigation by Vernon Geberth. A body exposed to the air for one week is generally equivalent to a body in water for two weeks. However, there are a list of variables, including large amounts of chemical waste, or bacteria, which can accelerate decomposition, Geberth writes. Generally, hands swell after several days, outer layers of skin separate from the body within 6 days, and sea vegetation begins to grow within 8 to 10 days, Geberth adds. But much deeper levels of water with great amounts of oxygen could pose a difficulty in estimating times of death, according to the new Canadian research. "When bodies or body parts are recovered, such information may also be valuable in estimating a minimum submergence time and indicating types of waters or habitats to which the remains may have been exposed," added Anderson, the criminologist.
Pig Studies Shed Light
Earlier studies may have been inaccurate.