Studies on Diatom Diversity of Various Water Bodies ofThe State Tripura (India) for Forensic Analysis

Abstract

Diatoms are unicellular algae characterized by their unique silica frustules, inhabiting a variety of aquatic and terrestrial ecosystems. They play a crucial role in forensic science, particularly in determining the cause and location of drowning deaths. Detection of diatoms in vital distant body organs can help establish if drowning occurred before death. In Tripura, a small hilly state in the north-east India, there is a significant annual incidence of drowning cases with no existing diatom database. A recent study conducted across four out of eight districts of Tripura, aims to establish a comprehensive diatomological database to aid forensic experts in drowning investigations. The study identified 74 species of diatoms belonging to 34 genera and 22 families under 11 orders of the class Bacillariophyceae across different districts with some species common among all districts, while others are exclusive to specific regions, showcasing a diverse range of diatoms. Among them, there are 11 species from both the Bacillariaceae and Naviculaceae families, 8 from Gomphonemataceae, 7 from Fragilariaceae, 5 from Pinnulariaceae, and 4 each from Achnanthidiaceae, Cymbellaceae, and Sellaphoraceae, along with 2 species each from Aulacoseiraceae, Catenulaceae, Diadesmidaceae, Pleurosigmataceae, Stephanodiscaceae, and Rhopalodiaceae, and 1 species each from the families Achnanthaceae, Brachysiraceae, Eunotiaceae, Mastogloiaceae, Melosiraceae, Neidiaceae, Stauroneidaceae, and Surirellaceae. The West District recorded the highest diversity with 35 species, followed by Sepahijala with 30 species, Unakoti with 16 and Gomati with 14 species. Interestingly two species are of common occurrence among all the four districts, while some were exclusive to certain regions. Twenty-one species were exclusively found in the West district, where as, seventeen species were restricted only to the Sepahijala district. Likewise, ten species were limited to the Unakoti district and seven species were found solely in the Gomati district. Certain species are unique to specific regions, underscoring notable variations in diatom distribution across different water bodies. Moreover, this study adds 72 species to the previous record of 21 species of diatom recorded by Das et. al. in 2010. The diverse distribution of diatoms across various water bodies can help connect drowned individuals to specific sources of water. This information may be vital in determining the location of a drowning incident, thereby aiding in the resolution of drowning related mysteries.