The idea that plants tell us about the dead certainly sounds like a horror movie but, although this may seem like fiction, the truth is that, sometimes, people die in unusual places, such as a desert, a forest or even during a war conflict. On many occasions, the body never recovers and loved ones cannot say goodbye to their relatives. Furthermore, if it is a case of murder or genocide, those responsible go unpunished by not being able to recover the body of the victim.
Plant detectives?
Since 1980, the Center for Forensic Anthropology at the University of Tennessee (USA) has probed the depths of the most macabre science: the decomposition of human bodies . Known colloquially as the Body Farm , in this field scientists examine how donated corpses decompose, so the microbiomes within us go haywire after death …
What if that burst of nutrients changed the color and reflectance of a tree’s leaves? And, if so, what if law enforcement authorities could use a drone to scan a forest, looking for these changes to find deceased missing persons?
Now, a team of scientists published in the journal Trends in Plant Science , the possibility of using the tree cover and the plants themselves in corpse recovery missions, by detecting changes in the plant’s chemistry as signs of nearby human remains. Although the impact of human decay on plants has yet to be fully explored, the researchers outline the steps required to make recovery of the body using vegetation a reality.
“In smaller open landscapes, foot patrols could be effective in finding someone missing, but in more forested or treacherous parts of the world like the Amazon, that won’t be possible,” says Stewart, a co-author of the paper. Of course, in the forests, which are usually places where there is more possibility of getting lost or where murderers seek to hide evidence, it is something else.
“This led us to consider plants as indicators of human decay, which could lead to faster and possibly safer bodily recovery ,” says Stewart.
Necrobioma
And it is that as a large mammal, such as a human being, decomposes in a forest, this process transforms the soil in various ways. The body’s “necrobiome”, all the bacteria that were already in it when it was alive, replicates rapidly in the absence of an immune system. This necrobiome mixes with microbes on the ground.
“The soil microbiome will change and, of course, the roots of the plants will also feel some changes; but we really don’t know what those changes are, “continues the expert.
“The most obvious result would be a large release of nitrogen into the soil , especially in the summer when decomposition occurs faster,” he says. Plants fed a high nitrogen diet produce more chlorophyll and therefore have greener leaves.
Is this the way to go?
Researchers have begun the process of studying the spectra of light reflected from plants growing at the University of Tennessee Corpse Farm to see if there are notable differences based on how close the plants are to bodies . They even propose that certain plants, particularly invasive species, might be more likely to flourish where a human has died.
Anyway, this is still a theory. Scientists are beginning to collect data on how plants might respond to human corpses, but inquiring about this possibility, with the technology, seems quite interesting to the forensic world. It will still take several years to be able to use plants as search tools in body recovery missions. But in the meantime, a team of botanists, anthropologists and soil scientists are already immersed in their research at the body farm, designing their first set of plant and corpse experiments.
Referencia: Holly Brabazon, Jennifer M. DeBruyn, Scott C. Lenaghan, Fei Li, Amy Z. Mundorff, Dawnie W. Steadman, C. Neal Stewart. Plants to Remotely Detect Human Decomposition? Trends in Plant Science, 2020; DOI: 10.1016/j.tplants.2020.07.013
