Could plants help us find dead bodies? Forensic botanists want to know


Date:
September 3, 2020
Source:
Cell Press
Summary:
Search teams looking for human remains are often slowed by
painstaking on-foot pursuits or aerial searches that are obscured
by forest cover.

Researchers are now discussing utilizing tree cover in body
recovery missions to our advantage, by detecting changes in the
plant's chemistry as signals of nearby human remains.



FULL STORY ========================================================================== Search teams looking for human remains are often slowed by painstaking
on-foot pursuits or aerial searches that are obscured by forest cover. In
a Science & Society article appearing September 3 in the journal
Trends in Plant Science, the authors discuss utilizing tree cover in
body recovery missions to our advantage, by detecting changes in the
plant's chemistry as signals of nearby human remains. Though the impact
of human decomposition on plants has not yet been thoroughly explored,
the researchers outline the steps needed to make body recovery using
vegetation more of a reality.


==========================================================================
"In smaller, open landscapes foot patrols could be effective to find
someone missing, but in more forested or treacherous parts of the world
like the Amazon, that's not going to be possible at all," says senior
author Neal Stewart Jr., a professor of plant sciences at the University
of Tennessee.

"This led us to look into plants as indicators of human decomposition,
which could lead to faster, and possibly safer body recovery." Research
into the relationship between plants and human decomposition will take
place on the University of Tennessee's "body farm." Officially known as
the Anthropology Research Facility, this is where scientists examine
the process of human body decay under different conditions. There, investigators will assess how "cadaver decomposition islands" -- the
zone immediately surrounding humans remains -- change the nutrient concentrations of the soil, and how those changes manifest in the
nearby plants.

"The most obvious result of the islands would be a large release of
nitrogen into the soil, especially in the summertime when decomposition
is happening so fast," Stewart says. "Depending on how quickly the plants respond to the influx of nitrogen, it may cause changes in leaf color
and reflectance." However, other large mammals, like deer, may also
die in the places people go missing. So, one hurdle the research must
overcome is finding metabolites specific to the breakdown of humans. As
humans typically have non-wild diets, there may be specific metabolites,
like those from drugs or food preservatives, that have specific influences
on plant appearance. "One thought is if we had a specific person who went missing who was, let's say, a heavy smoker, they could have a chemical
profile that could trigger some sort of unique plant response making them easier to locate. Though at this stage this idea is still farfetched,"
Stewart remarks.

Once the influences of cadaver metabolites on plants are better
understood, search teams could develop imagers to scan plants for
specific fluorescence or reflectance signals that indicate human remains
are close by. While some of this technology already exists, scientists
still need to know which species of plant and the appropriate signals to
look for. "We've actually built a whole plant imager that can analyze fluorescence signatures," says Stewart. "But the first steps are going
to be very fine scale, looking at individual leaves and measuring how
their reflectance or fluorescence changes over time when plants are
near human remains." Once diagnostic spectra are compiled, researchers
can begin to think about scaling up to drones and other tech that can
analyze a wide stretch of area in a short time.

"When you start to think about deploying drones to look for specific
emissions, now we can think of the signals more like a check engine
light -- if we can quickly fly where someone may have gone missing and
collect data over tens or even hundreds of square kilometers, then we'd
know the best spots to send in a search team," Stewart remarks.

While these ideas are exciting, we are still several years away from
feasibly using plants as search tools in body recovery missions. In the meantime, a collaborative team of botanists, anthropologists, and soil scientists will begin working at the body farm, designing their first
set of plant-cadaver experiments.


========================================================================== Story Source: Materials provided by Cell_Press. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. 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 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200903133025.htm

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