The inexplicable demise of almost two thousand individuals on the banks of Africa's Lake Nyos perplexed researchers for many months, until they unearthed a lethal secret concealed deep within the reservoir's depths.
Degassing of Africa's Lake Nyos / © wikimedia.org
Four decades ago, in August of 1986, Cameroon suffered an extraordinary natural catastrophe when a sudden liberation of gas from the Lake Nyos crater led to the death of almost 1,800 local residents overnight. The widespread annihilation of humans and animals in neighboring villages transpired without any indication of alarm or infrastructural damage, which for a long time bewildered international specialists.
IFLScience details the investigation into one of history’s most enigmatic disasters, along with the distinctive engineering approach utilized to cleanse this reservoir.
The quest for the unseen slayer
Following the discovery of the corpses, specialists initially suspected an outbreak of a highly transmissible virus or a deliberate chemical strike, given that all homes and fields were left entirely undamaged. Later, volcanologists proposed an underwater eruption, given the lake’s location within a crater; however, the water did not increase in temperature, and the characteristic mineral deposits were absent from the lakebed. A similar occurrence two years prior at Lake Monun, which saw 37 fatalities under mysterious circumstances, aided in deciphering the riddle.
Subsequently, geologist Haraldur Sigurdsson procured samples of deep water that quite literally exploded upon reaching the surface. The investigator ascertained that the lethal agent was carbon dioxide of volcanic origin, incessantly exuding from the Earth’s core through profound fissures in the seabed.
The workings of a natural explosive and its detoxification
Scientists clarified that at depths exceeding 200 meters, the union of cool temperatures and immense pressure enables the water to contain considerable volumes of dissolved carbon dioxide. Nevertheless, any trivial stimulus—for instance, a minor earthslide or a potent draft—is capable of destabilizing this equilibrium. This initiates a chain reaction: the gas is discharged, generating bubbles that surge swiftly upwards, pulling additional quantities of water and instigating a colossal gas outburst.
“The notion that a lake could independently execute this was beyond all anticipation, as lakes typically do not explode and cause such fatalities,” remarked ecology professor George Kling.
To forestall further catastrophes, in 2001, engineers implemented a solution remarkable in its simplicity: they positioned a broad pipe down to the reservoir’s floor, operating akin to an ordinary straw, which harmlessly emits carbon dioxide into the atmosphere. Since 2019, this degassing procedure has become entirely self-maintaining, consequently enabling Lake Nyos to be officially recognized as secure for inhabitants of the adjacent valleys.
As a reminder, Mount Erebus in Antarctica not only conceals one of the planet’s few permanent lava lakes, but this most puzzling volcano on Earth also ejects thousands of dollars in gold particles into the sky each day.
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Source: tsn.ua