Diatoms, Forams, Phytoliths and Pollen

• Type of eukaryotic algae • Found in bodies of water or near it • Make up most of the sequestration of carbon

• Enter the body during drowning • but have to be careful because diatoms can be consumed in foodstuff, inhaled in low quality cigars, and contamination of equipment

• diverse group of species with small size range which makes their entry inside organs feasible • Hard silica wall - resistant to chemical changes • can be recovered when little other evidence is available • growth corresponds to certain specific parameters of the environment (cause and site of death can be determined) • loads of different species

• identify them • hydrogen peroxide fixing • transition light microscope • SEM microscope

• not all diatoms will transfer onto a material • smoother surface diatom is less likely to transfer compared to a diatom with spines • species morphology affects the level of transfer and persistence from a water source to clothing or footwear

• cross-contamination • secondary transfer

• molecular barcoding combined with big-data approaches - rapid tracing and identification • automated AI - speed up identification workflows enabling the usage of diatoms

• single celled organism • live on the sea floor • can be found in sand and linked to certain beaches

• plant microfossils made of silica • found in some plant tissue • persist after the death and decay of plants • released into soil after plant death

• wind • water • animals

• hard coat to protect them - relatively resistant to destruction • surface texture is diverse and identifiable to particular plants • a single anther will produces thousands of pollen grains • easily dispersed • small size

• lack of skilled people in handling and identification - high chances of contamination • limited national or international databases of pollen

• pollen chemically processed and prepared for identification and methodology • SEM considered the standard but is time consuming • semi-automated TLM & fluorescence - rapid and accurate alternative • molecular barcoding with high throughput sequencing - future

• clothes • hair • drugs • soils • vehicles • stomach contents