Bridget Thurn samples the corpse flower scent. Credit: Botanic Gardens of Sydney
The titan arum, which blooms infrequently and only for a short time, gives off a powerful scent of rotting flesh to attract pollinators. This smell earned it the nickname corpse flower.
While most people don’t take the flower’s name literally, forensic scientist Bridget Thurn is not one of them.
“I study human remains—specifically the odor of decomposition," said Thurn, a professor of forensic chemistry at the University of Technology Sydney. “When I heard the corpse flower was blooming, I thought, 'Does it really smell like human decomposition? What chemical compounds does it produce?'”
Over the years, Thurn’s research has focused on the chemical profile of human remains, and how this profile changes. The aim is to develop technology that can help locate victims of mass disasters.
In fact, each year, Thurn and other University of Technology Sydney researchers conduct a large-scale disaster recovery exercise, together with defense, police and emergency services, at the Australian Facility for Taphonomic Experimental Research. The team covers human donors with rubble to mimic disaster conditions and collects odor samples over 1 to 2 weeks.
“The results are crucial for refining detection methods,” said Thurn. “We’re the only group conducting disaster trials like this, so our research is filling a major gap.”
That’s why when Thurn heard a corpse flower was going to bloom nearby for the first time in 15 years, she was interested in more than a personal capacity.
The flower—aptly named Putricia—began unfurling around 1:00 pm on Thursday, January 23 at the Royal Botanic Garden Sydney. Equipped with sorbent tubes connected to small vacuum pumps in order to trap volatile compounds, Thurn collected samples every two hours from 4:00 pm until midnight, continuing the next day from noon until 10:00 pm. She described the initial scent as “a combination of old laundry, a bakery and sulphur,” but by day two, it had evolved into “a much more musky and aged smell, more like cheese.”
After 36 hours, the blooming event was over, leaving Thurn with her samples of trapped volatile compounds to analyze in the lab.
The corpse flower’s distinct smell is an adaptation evolved to attract insects for pollination. Human decomposition odors are also shaped by complex biological processes. Thurn said this shared chemical landscape makes the comparison between the corpse flower and human decomposition particularly fascinating.
“Some papers have found overlapping compounds between the two, but I’m interested to analyze my database to see what’s really going on. Does the corpse flower’s smell accurately mimic decomposition? Does it live up to its name?” the professor said.
Thurn’s latest paper, published in the September 2024 issue of Forensic Chemistry, discusses key antemortem and postmortem volatiles emitted from humans, as well as critical biomarkers for the development of search methods for missing persons.
“Determining the complete human odor profile will assist in victim location where living and deceased individuals are commingled (e.g. disaster sites), and will inform future technologies to aid in accelerating search-and-rescue operations,” writes Thurn.