A preliminary study characterizing temporal changes in soil bacterial communities after dismembered bones were buried

Area of Science:

• Forensic Science
• Microbiology
• Environmental Science

Background:

• Accurate determination of burial time for skeletal remains is crucial in forensic investigations.
• Existing postmortem interval prediction models often focus on whole bodies or lack specificity for dismembered remains.
• Soil microbiome dynamics offer a potential avenue for estimating burial duration, particularly for bone decomposition.

Purpose of the Study:

• To investigate the feasibility of using gravesoil microbiome changes to predict the burial time of dismembered bones.
• To analyze the temporal succession of bacterial communities in soil associated with decomposing porcine femurs.

Main Methods:

• Conducted 16S rRNA amplicon high-throughput sequencing on gravesoil samples from porcine femurs buried over 120 days.
• Analyzed changes in soil microbial diversity and community structure.
• Developed predictive models (multiple linear regression and random forest) using time-related bacterial families.

Main Results:

• Observed a higher Shannon index (microbial diversity) in bone-containing burial soil compared to control soil.
• Identified 61 time-related bacterial families, with specific families like Thermomonosporaceae and Clostridiaceae being key indicators.
• Developed predictive models with mean absolute errors of 56.69 (linear regression) and 55.65 (random forest) accumulated degree days.

Conclusions:

• Microbial successional changes in gravesoil can effectively predict the burial time of dismembered bones.
• This study provides empirical evidence supporting the use of soil microbiome analysis for estimating postmortem intervals of bones.
• Findings contribute to understanding the impact of bone decomposition on surrounding soil bacterial communities.