Profiling of Successional Microbial Community Structure and Composition to Identify Exhumed Gravesoil—A Preliminary Study

Abstract

Advancements in molecular microbial ecology techniques have enabled researchers to study the complex interactions of epinecrobiome, necrobiome, and thanatomicrobiome communities during cadaver decomposition within novel forensic disciplines. This preliminary study tracks shifts in subsurface soil necrobiome as indicators of time-since-exhumation where whole juvenile Sus scrofa domesticus was used as the human cadaver proxy. Principal component analysis of DGGE-based diversity index (Shannon-Weiner, HꞋ; Simpson (D)) measurements showed more consistent delineation of pre- and post-exhumation periods of the fungal 18S gene with further clustering for days 270 and 300. More importantly, high-resolution metabarcoding of the 16S rRNA gene recorded temporal bacterial clock indicators at order and family levels. Specifically, Xanthomonadales (11.29%) and Xanthomonadaceae (4.27%), and Verrucomicrobiaceae (4.00%) were abundance-based season (spring–summer) and microbial clock indicators for post-burial interval (PBI) ≥ 150 days. Hydrogenophilales (7.13%) and Hydrogenophilaceae (7.56%), Clostridiales (4.57%) and Clostridiaceae_1 (3.13%), and Bacteroidales (3.33%) defined the impacts of 120 days since exhumation of Sus scrofa domesticus. They could, therefore, be tracked to identify grave emptying for the current soil type.