Investigators may be able to use the results to pinpoint the location of missing bodies from a distance.
In a first-of-its-kind study, criminologists at a university in British Columbia, Canada, are studying decomposing pig carcasses to better understand how human bodies break down hundreds of feet below the ocean’s surface.
The study, out of Simon Fraser University and published in the journal PLOS ONE, showed that the decaying process deep underwater is dramatically different than what takes place in shallower Pacific waters.
The authors of the study, forensic specialists Gail Anderson and Lynne Bell, strapped the bodies of several pigs to metal grates and deposited them at a depth of 300 meters (984 feet), beneath a pre-existing state-of-the-art deep-sea monitoring installation. The installation is part of the VENUS observatory network, which can stream on-site video in real time, as well as measure the turbidity, temperature, salinity, and oxygenation of the water.
Near the ocean’s surface, pig bodies can last for weeks or even months, explained Anderson in an interview with The Vancouver Sun. However, 300 meters below the surface, the bodies were reduced to bone in as little as three to four days, depending on the season.
While watching the on-site video documenting the decomposition, Anderson described a colony of amphipods, commonly known as sea lice, swarm the animals’ bodies, driving away other scavengers such as spot prawns and crabs.
“They just covered the bodies in four-to-five-inches-deep layers of amphipods, which just inhaled — basically ate — the entire carcass, inside out,” she told The Vancouver Sun.
“Once in awhile a fish would swim over the top and knock some of the amphipods off and you’d see the skin was still intact, so they were going in through the orifices and removing all the soft tissue.” Anderson continued.
One of the pigs on Day 0 of the fall trial. Photo credit: Ocean Network Canada’s VENUS observatory. Image has been cropped.
Monitoring equipment also measured a sharp decrease in oxygen levels around the carcass. “That’s not been seen before,” Anderson explained to The Vancouver Sun. “It would seem that when you’ve got that vast number of animals feeding in a frenzy on a body like that, that they actually deplete oxygen from the water, which is amazing.”
Anderson speculated that this de-oxygenation, coupled with the noise created from the mass of moving creatures, may one day allow investigators to pinpoint the location of missing bodies from a distance. “We’re not there yet,” she said. “But maybe in the future.”
Pigs are often used in forensic research because of their similarities to humans, including their relative hairlessness, similar torso size, and omnivorous diet.
Anderson and Bell will move their experiment to even deeper waters using other VENUS sites located further offshore and at depths up to two kilometers (1.2 miles). The results should help forensic investigators learn more about bodies recovered at depth.
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