Deep in the mountains of Uzbekistan lives a colossal scarlet mushroom that thrives on a diet of toxic mercury.
A crimson giant
In the remote Boysun mountains of southern Uzbekistan, a unique organism shows the limits of life. Known as the Boysun scarlet colossus, its scientific name is Cinnabarinus colossus boysunensis. The fungus produces massive fruiting bodies that can reach up to 70 centimeters in height and 100 centimeters in diameter, with a distinctive scarlet cap. This color is not a simple pigment but a complex organomercury compound, a direct byproduct of the fungus's strange diet.
Like Earth's largest known organisms, such as the Armillaria ostoyae fungus in North America, the true bulk of C. colossus lies underground. Its mycelial network, a vast web of fungal threads, is estimated to cover several square kilometers beneath the soil, making each network a single, massive individual. The organism's size matches its extreme biology. It has evolved to tolerate and to actively metabolize, one of the planet's most toxic heavy metals.
A diet of toxic metal
The Boysun district is part of the South Tian Shan mountain system, a region with a complex geology known for deposits of various rare metals, including mercury. Ancient marine shales and volcanic rocks in the area contain anomalously high concentrations of the element. It is in the soil derived from these formations that C. colossus thrives. The fungus employs a sophisticated system of mycoremediation to process the mercury, which is lethal to almost all other forms of life.
The process begins with biosorption, where mercury ions are bound to the cell walls of the fungus's hyphae. From there, the metal is transported into the cells and sequestered by specialized proteins called metallothioneins. Unlike other fungi that simply store the toxin, C. colossus possesses a unique enzyme, a mercury reductase, which is part of a metabolic pathway that strips electrons from the mercury compounds. This chemosynthetic process provides the fungus with energy. The detoxified, elemental mercury is either sequestered in the scarlet cap or slowly released as a vapor. This biochemical adaptation makes the fungus a master of its toxic environment, actively cleaning the soil as it grows. Fungi have been documented to perform bioremediation of other toxic substances, including arsenic and radioactive waste.
💡Fun Facts
The bright scarlet color of the mushroom's cap is an organomercury pigment, a compound found nowhere else in nature.
The underground mycelial network of a single *C. colossus* can be thousands of years old, similar to other giant fungi.
The fungus was first documented by Soviet geologists in the 1970s who were surveying the region for mineral deposits.
Its metabolic process reduces soil mercury levels by up to 80% in its immediate vicinity, allowing other plants to grow in an otherwise sterile environment.
Accessible 24/7; this is a wild, natural site in a remote mountain range.
Admission
Free.
Accessibility
Extremely difficult. Reaching the habitat of *C. colossus* requires a multi-day trek through rugged, unmarked mountain terrain. A local guide is essential. The area is not serviced by roads.
Boysun scarlet colossus mushroomSurkhandarya Region, Uzbekistan