Human Decomposition Ecology at the University of Tennessee Anthropology Research Facility

The University of Tennessee Anthropology Research Facility (ARF) is well known for its unique history as a site of human decomposition research in a natural environment. It has been integral to our understanding of the processes of human decomposition. Over the last 30 years 1,089 bodies have decomposed at this 1.28 acre facility, producing a density of 850 corpses per acre of land. This project evaluated the abiotic and biotic characteristics of the soil exposed to various levels of human decomposition in order to determine the effect on the physicochemical properties and the indigenous bacterial communities.

Specifically, 75 soil samples were taken to determine abiotic properties. A biological matrix was generated for the 40 samples inside the facility based on sequencing of the 16S rDNA gene. The identified taxonomy was evaluated for differences among decomposition bins and taxa.

Results of the abiotic soil properties demonstrated few differences among the predefined bins of decomposition density. Significant differences were observed between samples inside the facility to the negative control, and to those samples taken below actively decomposing corpses. When taken together, the abiotic data demonstrated a temporal shift away from control, with the greatest deviation at 18 to 24 months. After which time, the samples became more similar to control samples.

Similarly, the biotic data remained concordant with the abiotic data, but demonstrated significant differences between the areas of high decomposition to those with no history of decomposition. The high decomposition bins were marked by high levels of chemoorganotrophic and sulfate-reducing bacteria, and a reduction in Acidobacteria, indicating a change in the community of underlying bacteria in response to carcass enrichment and ammonification of the soil.

Thirty years of decomposition research at the ARF has forced a shift in the underlying bacterial community in response to the enrichment of the soil with increased nitrogen and carbon-containing compounds. The baseline data presented in this work provides a control dataset for further exploration regarding the biogeochemical relationships among microbial organisms, soil characteristics, and cadaver decomposition. Within this relationship exists the potential for developing new models relating to postmortem interval estimation and clandestine grave location.