Spatial Impacts of a Multi-Individual Grave on Microbial and Microfaunal Communities and Soil Biogeochemistry

• NCJ Number: 254317
• Journal: PLoS ONE Volume: 13 Issue: 12 Dated: 2018
• Author(s): Sarah W. Keenan; Alexandra L. Emmons; Lois S. Taylor; Gary Phillips; Allison R. Mason; Amy Z. Mundorff; Ernest C. Barnard; Jan Davoren; Jennifer M. DeBruyn
• Date Published: 2018
• Length: 12 pages
• Grant Number(s): 2017-R2-CX-0008; 2016-DN-BX-0178
• Agencies: NIJ-Sponsored
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored)
• Award: Establishing a Rank Order for Skeletal Element Sampling: Examining Differential DNA Yield Rates Among and Between Buried Human Skeletal Elements as Compared to Surface Recovered Skeletal Elements; Soil fungal and nematode community changes as a methodology for determining long-term postmortem interval after cadaver mass loss

Annotation

This study assessed the impact of human decomposition in a multi-individual, shallow (~70 cm depth) grave on soil biogeochemistry and soil microbial and nematode communities.

Abstract

Three individuals were interred and allowed to decay for 4 years. Soils were collected from two depths (05 and 30-35 cm) along linear transects radiating from the grave as well as from within and below (85-90 cm depth) the grave during excavation to assess how decomposition affects soil properties. Along radiating surface transects, several extracellular enzymes rates and nematode richness increased with increasing distance from the grave, and likely reflect physical site disruption due to grave excavation and infill. There was no evidence of carcass-sourced C and N lateral migration from the grave, at least at 30-35 cm depth. Within the grave, soils exhibited significant N-enrichment (e.g., ammonium, dissolved organic N), elevated electrical conductivity, and elevated respiration rates with depth. Soil biogeochemistry within the grave, particularly in the middle (30-35 cm) and base (70-75 cm depth), was significantly altered by human decomposition. Mean microbial gene abundances changed with depth in the grave, demonstrating increased microbial presence in response to ongoing decomposition. Human-associated Bacteroides were only detected at the base of the grave where anoxic conditions prevailed. Nematode community abundance and richness were reduced at 70-75 cm and not detectable below 85-90 cm. Further, the analysis identified certain Plectus spp. as potential indicators of enrichment due to decomposition. This project demonstrated that human decomposition influences soil biogeochemistry, microbes, and microfauna up to 4 years after burial. (publisher abstract modified)