Diatom Colonization on Cowhide Substrate in Batang Kuranji River, Padang City, for Forensic Drowning Diagnosis

<b>Background and Objective:</b> Diatoms are unicellular algae that can survive extreme conditions because of their silica-based cell walls. As an indication of the murder scene and the duration of the victim's drowning, diatoms might be utilized for forensic diagnosis. The purpose of this study is to determine the diatom species that colonize the cowhide substrate, the community and the relationship between physico-chemical factors in the Batang Kuranji River in Padang City. <b>Materials and Methods:</b> Drowning diagnosis was investigated by submerging cowhide substrates at sampled river sites to collect colonizing diatoms over 10 days. Diatom samples were collected, preserved and identified microscopically, while key water quality parameters were measured concurrently. Statistical analysis, including ANOVA and PCA, was used to correlate diatom colonization with location, submersion time and environmental factors. <b>Results:</b> It showed that diatom colonization based on the number of species on the 8th day showed colonization influenced by an increase in the number of individuals, such as the species <i>Fragilaria capucina</i> and <i>Synedra ulna</i>. In the observation, 94 species of diatoms were found, 42 species were obtained as a pointer to the crime scene of the drowning victim and 68 species as a pointer to the time of the victim's drowning. Diatoms on cowhide substrate consisted of 2 classes, 2 orders and 19 families with diatom density ranging from 3.81±0.16 to 22.80±1.34 ind/cm<sup><a href="190599_op">2</a></sup>. The highest relative density was <i>Fragilaria capucina</i> (28.59%). <b>Conclusion:</b> The diatom community that was identified had no dominant species, an equally distributed individual population and diversity index requirements that were categorized as moderate to high. The Batang Kuranji River's chemical and physical factors are still largely ideal for diatom colonization on cowhide substrates, according to the PCA analysis's results, which can also serve as a guide for drowning victims.