Assessing Diatom Community Shifts with Salinity During Decomposition of Partially Submerged Buried Cadavers

Diatoms are adaptable microbes that have numerous uses in areas including environmental monitoring and drowning investigations. Due to the ongoing exposure to moisture and changing conditions, traditional forensic techniques for detecting and estimating the postmortem interval (PMI) of partially submerged cadavers are frequently inefficient in aquatic situations. To ascertain the PMI and the location of partially submerged burial remains, this study sought to assess the efficacy of diatoms as biological indicators. This study was conducted in freshwater and brackish water ecosystems, where the fatty flesh of commercial Sus scrofa was buried in a shallow grave and allowed to decompose at several designated sampling points for 270 days of burial interval. Benthic diatoms were sampled from the associated soils to determine their abundances at each decomposition stage. Notably, several diatom species were identified as potential PMI indicators, including Caloneis silicule (freshwater) and Chaetoceros coarctatum (brackish water). Species potentially useful for locating submerged cadavers including Cosinodiscus argus for freshwater systems and Fragilaria crotonensis for brackish water. Additionally, strong correlations between certain diatoms (Navicula cancellata, Fragilaria vaucheriae, Hantzchia sp., Nitzschia closterium, and Coscinodiscus gigas) and lipid content further underscore their potential to be used in forensic investigations.