Evaluation of Postmortem Decay Processes in the Underwater Environment of the Black Sea Using A Rat Model: Seasonal, Biological and Microbial Dynamics

Öz

Aim: The aim of this research is to evaluate the diversity of necrophagous fauna specific to the Black Sea ecosystem and the effect of these organisms on postmortem decay processes from a seasonal perspective. In the experimental study carried out off the coast of Sinop, on the Black Sea coast of Türkiye, rat samples were used to represent human cadavers. In the study covering the spring (April-May 2024) and winter (December 2024–January 2025) periods, the subjects were fixed to the seabed at a depth of 13 meters and followed with daily dive observations for 92 days. Environmental variables such as water temperature, pH, salinity and biotic interactions were regularly recorded throughout the process. Methods;The decay process was analyzed at both macroscopic deformation and microbial level. The spatial distribution of deformation was reported in detail, classified on the basis of body regions. Additionally, tissue hardness measurements were performed under underwater conditions with a Shore A type durometer and temporal changes were monitored with quantitative data. In the analyses of necrophagous communities, the distribution of scavenging species specific to the Black Sea was listed in detail, and it was determined that species richness and biological interactions were higher in the winter period. Results and Conclusion; Metagenomic sequencing data revealed that sulfate-reducing bacteria such as Sulfurovum, which are particularly effective in anaerobic environments, are dominant, while the Aenigmarchaeota phylum of the Archaea domain shows low diversity. The results highlight the importance of biological and environmental indicators in underwater forensic cases.

Anahtar Kelimeler

• Forensic taphonomy
• Necrophagous fauna
• Dynamics of decomposition
• Underwater scavenging species of the Black sea
• Underwater corpses
• underwater postmortem transformation process

Karadeniz’in Sualtı Ortamında Ölüm Sonrası Bozunma Süreçlerinin bir Sıçan Modeli Kullanılarak Değerlendirilmesi: Mevsimsel, Biyolojik ve Mikrobiyal Dinamikler

Öz

Amaç: Bu araştırmanın amacı, Karadeniz ekosistemine özgü nekrofaj fauna çeşitliliği ile bu organizmaların postmortem çürüme süreçlerine etkisini mevsimsel açıdan değerlendirmektir. Türkiye’nin Karadeniz kıyısında, Sinop ili açıklarında gerçekleştirilen deneysel çalışmada, insan kadavralarını temsilen sıçan örnekleri kullanılmıştır. Bahar (Nisan-Mayıs 2024) ve kış (Aralık 2024–Ocak 2025) dönemlerini kapsayan çalışmada, denekler 13 metre derinlikteki deniz tabanına sabitlenerek 92 gün süresince günlük dalış gözlemleriyle takip edilmiştir. Süreç boyunca su sıcaklığı, pH, tuzluluk ve biyotik etkileşimler gibi çevresel değişkenler düzenli olarak kaydedilmiştir. Yöntem: Çürüme süreci, hem makroskobik deformasyon hem de mikrobiyal düzeyde analiz edilmiştir. Deformasyonun mekânsal yayılımı, vücut bölgeleri bazında sınıflandırılarak ayrıntılı şekilde raporlanmıştır. Ayrıca, Shore A tipi durometre ile su altı koşullarında doku sertliği ölçümleri gerçekleştirilmiş ve zamansal değişim nicel verilerle izlenmiştir. Bulgular: Nekrofaj topluluklara ilişkin analizlerde, Karadeniz’e özgü leş yiyici türlerin dağılımı detaylı biçimde sıralanmış; kış döneminde tür zenginliği ve biyolojik etkileşimlerin daha yüksek olduğu belirlenmiştir. Sonuç: Metagenomik dizileme verileri, özellikle anaerobik ortamlarda etkili olan Sulfurovum gibi sülfat indirgen bakterilerin baskın olduğunu, Arkea domainine ait Aenigmarchaeota şubesinin ise düşük çeşitlilik gösterdiğini ortaya koymuştur. Sonuçlar, sualtı adli vakalarda biyolojik ve çevresel göstergelerin önemini vurgulamaktadır.

Anahtar Kelimeler

• Adli tafonomi
• Nekrofag fauna
• Ayrışma dinamikleri
• Karadeniz’in sualtı leşçi türleri
• Sualtı cesetleri
• Sualtı postmortem dönüşüm süreci

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