This research compared the succession patterns in human cadaver decomposition in two deposition contexts, surface and shallow burial.
Decomposition is a dynamic environment populated by a complex network of communities, including mammalian, insect, and microorganism species that inhabit the death environment and prey upon the remains and each other. An emerging avenue of research has endeavored to use the bacteria inside a decomposing body, formerly the microbiome, and soil bacterial from the surrounding grave soil to connect the patterns of microbial succession with decomposition in estimating the postmortem Interval. Previous research has found bacterial succession patterns in surface deposited human cadavers; however, perpetrators may attempt to hide victim remains in shallow, clandestine burials. The differences in bacterial composition and succession patterns in a burial context is currently unknown. In the current study, four donated human cadavers were placed in the Texas State Forensic Anthropology Research Field located in San Marcos, Texas, in spring 2017. Two cadavers were buried in shallow graves (45.72 cm and 40.64 cm) and two deposited on the soil surface. Using alpha diversity evenness, two general trends were observed. First, the buried cadavers exhibited one major period of more uniform bacterial composition. Second, the surface cadavers exhibited two such events. While the surface cadavers displayed similar patterns of bacterial succession to one another, the buried subjects exhibited greater variation in time between cadavers. (publisher abstract modified)