Phoenixes aren't the sole survivors of the flames
The phoenix, a mythical creature from ancient Greek and Egyptian lore, symbolizes renewal through fiery destruction. As the phoenix reaches the end of its life, it erupts into flames with a resounding cry, only to emerge anew from the ashes as a fledgling. While the phoenix itself remains a legend, its motif has permeated various works of fiction, from the Harry Potter series to the anime One Piece. Although real phoenixes don't exist, science has uncovered remarkable examples of organisms capable of withstanding extreme heat and even regenerating from apparent destruction, echoing the mythical rebirth of the phoenix.
Tardigrades renowned for their resilience, capable of surviving extreme conditions such as the vacuum of space. However, despite their impressive endurance, these tiny creatures struggle when faced with a warm day at the beach. Accustomed to the cool, damp environment of moss, tardigrades begin to perish when temperatures range between 29° and 37° Celsius (84° and 99° Fahrenheit). In times of adversity, tardigrades can enter a state of suspended animation known as "tun," yet even in this state, they cannot endure temperatures exceeding 83°C (180°F) for more than an hour.
Robert Kelly, a chemical engineer and microbiologist from North Carolina State University in Raleigh, asserts that even the most moderate flame begins at temperatures around 600°C (1,110°F), a level of heat beyond the tolerance of any living organism.
When something ignites, the carbon present in its chemical composition reacts with oxygen to produce carbon monoxide and dioxide, a process known as combustion," explains Kelly. "Given that carbon is ubiquitous in all living organisms on Earth, none can withstand burning without appropriate protective equipment.
Kelly's research focuses on hyperthermophiles, organisms capable of surviving extreme temperatures. These single-celled life forms thrive in environments such as hot springs or deep-sea vents. While some hyperthermophiles are bacteria, the most resilient and heat-tolerant belong to the archaea domain, one of the three primary domains of life.
While not all archaea thrive in extreme heat, the ones under Kelly's scrutiny certainly do. These robust cells can withstand temperatures up to 120°C (250°F), significantly surpassing the boiling point of water. Kelly warns that if a person were to immerse themselves in the hot springs inhabited by these organisms, the intense heat would cause their skin to essentially disintegrate from their bones. At such scorching temperatures, he explains, meat, including human muscle, would instantly cook.
Surviving a fire
A phoenix might harness minuscule chemical reactions to maintain its protein structure, but sustaining an entire bird, even a fledgling, exceeds the capabilities of a single cell. Fortunately, certain creatures have evolved mechanisms to endure extreme heat, even amidst raging infernos.
In South Africa's fynbos, a parched landscape abundant with shrubs prone to wildfires, dwell diminutive beetles known as weevils. During a hike in 2018 through a recently scorched area, Marion Javal and her companions found inspiration. Javal, an entomologist specializing in insect studies at the Institute of Research for Development in Montpellier, France, was intrigued by the resilience of these creatures amidst such fiery adversity.
In the aftermath of the blaze, Javal and her companions encountered a multitude of minuscule weevils navigating the scorched terrain. "We observed a cluster of extremely diminutive weevils traversing the ground," she recalls, "remarkably tiny insects with limited flight capabilities." Their presence puzzled the observers, prompting speculation about the reasons behind their survival in such a perilous environment. Unlike their airborne counterparts, weevils incapable of flight found themselves immobilized amidst the flames. Being ectothermic organisms, insects maintain body temperatures in alignment with their surroundings. Consequently, as the air temperature soared during the wildfire, so did the body temperatures of these delicate insects. The question remained: How did these tiny, flightless creatures manage to endure the inferno?
Javal and her team undertook a series of experiments, collecting weevils from the fire-affected area to assess their heat tolerance. Among the species examined, Ocladius costiger demonstrated remarkable resilience, enduring temperatures as high as 52.6°C (127°F). Similarly, Cryptolarynx variabilis exhibited impressive heat tolerance, surviving temperatures of up to 53.4°C (128°F). "Discovering such elevated heat tolerance in these minute weevils was truly unexpected," remarks Javal. The findings of their research were documented and published in the journal Ecological Entomology in 2022, shedding light on the extraordinary survival strategies of these diminutive insects.
Javal suggests that the beetles may possess cellular adaptations aiding in their survival. Additionally, certain adult beetles exhibit behavior such as burrowing into the soil to escape the encroaching flames. Furthermore, some species of weevils lay their eggs within plants characterized by robust, woody exteriors. These resilient plants can endure the scorching temperatures of summer and wildfires, providing a protective haven for the weevil eggs nestled within. As the fires subside, the eggs remain unharmed, poised to hatch when conditions become favorable once more, akin to a phoenix emerging from the ashes.
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