Potential to Determine a Postmortem Submersion Interval Based on Algal/Diatom Diversity on Decomposing Mammalian Carcasses in Brackish Ponds in Delaware

• NCJ Number: 223886
• Journal: Journal of Forensic Sciences Volume: 53 Issue: 4 Dated: July 2008 Pages: 935-941
• Author(s): Kathryn Zimmerman B.Sc.; John R. Wallace Ph.D.
• Date Published: July 2008
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This study examined stillborn piglet decomposition in brackish water and semiquantitatively documented stages of decomposition, daily temperature of the water at each stage of decomposition, and the algal/diatom diversity useful in determining a postmortem submersion interval (PMSI).

Abstract

The study’s findings indicate that more research is required in examining the potential for using diatoms (a unique taxonomic division of algae represented by unicellular plants) in not only determining manner of death but also the duration of time a victim may have been immersed in water. Five stages of decomposition were determined for both brackish ponds used in the study: submerged, early floating, floating decay, advanced floating decay, and sunken remains. There was a significant amount of weight loss between the early floating stage and the advanced floating decay stage of decomposition. In Pond 1, diatom diversity was greatest during the early floating stage of decomposition for both piglets and ceramic tiles submerged with the piglets; however, in Pond 2, diatom diversity was greater on the stillborn piglet substrate during the early floating stage of decomposition compared to the tile substrate; the latter substrate contained a greater amount of diatom diversity during the floating decay stage of decomposition. Algal diversity as a function of time was significantly correlated in this study. An understanding that there is a significant relationship between algal diversity and time has been suggested as a methodology to estimate a PMSI. The equation generated in this study has the potential to be used to predict a PMSI; however, more work is needed in order to definitively use this in actual casework. Piglets and ceramic tiles were submerged in two brackish ponds and sampled regularly to document algal diversity and succession between substrates and stages of decomposition. 3 tables, 5 figures, and 25 references