From fictional shows like CSI Miami to real life crime scenes, we have all seen the process it takes to gather forensic evidence. If you haven’t, research has been recently gathered to come up with new and innovative ways to catch a criminal. Whether it be from derelict fields, dark alleyways, or deep sea, oceans, many environments can leave behind physical evidence of a criminal and victim that crime scene investigators both real and fictional can use to identify and catch the culprit. However, this can be difficult when trying to find the best pieces of evidence to use, and detect after analyzing and putting criminal information together.
According to researcher Kapil Verma of Amity Institute of Forensic Sciences (AIFS), microscopic algae, like diatoms for example, can be picked up from anywhere that there is water. This includes rivers, lakes, oceans and moisturized soils. Some domestic water supplies and even moist surfaces such as exposed rocks and sediment can harvest diatoms. While many diatoms traditionally have been used to diagnose deaths caused by drowning, research has now shown that the use of diatoms and their potential for use as traces of evidence in a range of forensic examinations has been useful throughout the field of forensic science.
Verma goes on the explain how a diatom diagnostic test for drowning is based upon the hypothesis that diatoms will not enter the systemic circulation and be deposited in such organs as the bone marrow unless the circulation is still functioning, thus implying that the decedent was alive in the water. This hypothesis is crucial when examining victims of violence crimes because examiners can further determine their cause of death and in some cases the location of where they died.
Most forensic investigations are carried out on dry land, but according to the Unites States Geological Survey (USGS), nearly 71% of the Earth’s surface is covered in water. Freshwater or marine environments, for example are often encountered as crime scene locations or sites of accidental suicide death or natural disasters.
When a crime is carried out on dry land, water may be then used by a criminal to dispose of incriminating evidence
How does microscopic algae play a role in the findings of criminal evidence?
Diatoms are a major group of eukaryotic algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although some form chains or simple colonies. A key characteristic feature of diatom cells is that they are encased within a unique cell wall made of silicate. These walls show a wide diversity in form and structure. Microscopic algae like diatoms are extremely useful when diagnosing drowning as a cause of death. Their microscopic size and inhabitants in flowing water means they are often inhaled and swallowed during drowning.
Diatoms are then transported throughout the circulatory system of the body, and deposited in various organs, including the brain, lung, and bone marrow. They can be observed under a microscope as well as compared to the diatoms in the water where the body was found. If diatoms are not present in the body during an examination, it may mean that the victim did not die by drowning, but instead if the diatoms in the organs are significantly different from those in the water that the body was found in, it may also mean that the victim has been deliberately drowned elsewhere and moved to the second location to make the cause of death seem accidental or even suicidal.
Research has demonstrated how diatoms can be used to estimate the time since death, which is a crucial piece of information in any forensic investigation. This is notoriously difficult to do in cases where the body has been found in water, with scientists often drawing conclusions based on the body’s level of decomposition and the presence of insects and bacteria.
This kind of work remains largely fixated in trial and error, but it is useful for establishing a timeline since submersion and or death in water.
Lost & Found
Seasonal variation in diatom abundance and diversity is used to generate floral profiles of aquatic habitats which can then be compared to specimens collected from body tissues or other materials recovered from the crime scene. Diatom tests are used routinely in the diagnosis of drowning and in estimating the postmortem interval, or time since death.
The reason why diatoms are becoming so useful in regards to forensic science is that they are so bountiful in different environments. Microscopic assessment of algae found on clothing, footwear and personal belongings have already provided evidence in cases including homicide, serious assault, and serial burglary across the US and Europe.
Seasonal variation in diatom abundance and diversity is used to generate floral profiles of aquatic habitats which can then be compared to specimens collected from body tissues or other materials recovered from the crime scene. Diatom tests are used routinely in the diagnosis of drowning and in estimating the postmortem interval, or time since death.
The reason why diatoms are becoming so useful in regards to forensic science is that they are so bountiful in different environments. Microscopic assessment of algae found on clothing, footwear and personal belongings have already provided evidence in cases including homicide, serious assault, and serial burglary across the US and Europe.
The collection of diatoms in a victim’s bone marrow represents a microbial “fingerprint” of the time and place where drowning occurred. Each lake, river, estuary contains a unique community of diatoms. The mix of species found in any given location also fluctuates over time, and varies according to season. The field of forensic science in relation to diatom analysis is fairly new but emerging with its potential for further research and usage.
Although aquatic systems are complicated and difficult for scientists to analyze, diatoms prove to be a reliable tool for crime scene investigation.
For more insights on forensic science and innovations in the field, check out my blog on 7 Facts About Forensic Science
Related source: How microscopic algae are helping forensic teams catch criminals
