“To Catch a Criminal”: Forensic Teams Catching Criminals due to Research on Microscopic Algae

There are plenty of crime shows on television for anyone interested in the genre. It is exciting to watch as Eric Delko or Sherlock Holmes solve crimes with evidence both mundane and unusual: blood spatter, fingerprints, ear prints, tire tracks, footprints and the omnipresent “DNA sample.” It all seems so obvious at the end because the evidence is everywhere.

However, did you know that another kind of trace evidence is found all around us in every habitat on earth? Microscopic algae known as diatoms are found anywhere on the planet where there are enough light and water. There are over 25,000 species of these single-celled animals and the largest is barely as wide as a human hair. Though appearing only as an amber sludge to the naked eye, under the microscope they show a variety of glass-like shapes. Diatoms have been called “algae in glass houses” because they resemble tiny glass clams. They are not glass, however, rather they are made of silicon dioxide and water.

Tiny and Important

It may sound like something out of a science fiction movie but it is a fact that diatoms have and continue to help forensic scientists solve crimes. It has been known since the early 1940s that diatoms only enter the human body if they are swallowed or inhaled. Amazingly, these tiny animals have helped solved countless numbers of cases of drowning. For example, a victim was alive when they were forced into the water if diatoms are found in their lungs, bloodstream or even the bone marrow.

The knowledge and study of diatoms have helped solve other cases such as suicides, accidental deaths, body dumps, and disasters (like floods.) Diatoms are important to forensic scientists because they can accurately help pinpoint soil or the smallest amount of water to a specific location. A tiny speck of mud or a water stain on the bad guy’s shoes can lead him directly back to where the victim was found.

Did the perp touch a tree in the forest before forcing his victim into a car? There are diatoms found in practically every kind of tree bark. Unique species of diatoms are found in every ocean, river, lake and pond in the world. Knowledge of the differences in sizes, colors, and shapes can be the difference between a cold case and a closed one.