Monday, December 3, 2012

Rapid seafloor decomposition of pig carcass (video)

As a vertebrate paleontologist, it's necessary to have a strong understanding of the manner in which modern animals decompose, as it can inform us of formative processes in the preservation of fossils. Fossils, after all, are all parts of dead organisms - and understanding the taphonomy - or "laws of burial" of modern and fossil organisms can guide us in interpreting the paleoecology of fossil species.

Here's a video that's been making its rounds on the science blogs from the deep sea experimental station VENUS, based at the University of Victoria in British Columbia. Several forensic experiments have been conducted with the station, which is effectively a seafloor, remotely operated laboratory connected to the internet. The pigs were dropped off in the area, and an ROV docked at the seafloor station went out and brought the carcasses to the station.

Here's a fantastic video of a pig carcass being consumed by isopod and decapod crustaceans at roughly 90 meters water depth:

What exactly does this sort of data tell paleontologists? For starters, if you count the days, you'll see that a medium-sized vertebrate carcass (although small with regards to cetaceans) can be consumed and skeletonized in about a week. This could suggest that once a carcass reaches the seafloor, there may be little opportunity for the carcass to refloat, for example. In other experiments at the same site conducted during a period of lower dissolved oxygen, skeletonization took place only after 40+ days at the seafloor. So, there is quite a bit of variability, depending upon a number of factors.

For the taphonomically inclined, much of the observations from the VENUS forensic experiments have already been published by Gail Anderson:

Anderson, G.S. 2009. Decomposition and Invertebrate Colonization of Cadavers in Coastal Marine Environments. In J. Armendt et al. (eds), Current Concepts in Forensic Entomology, p. 223-272.

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