Lake Nyos

In 1986, 1,700 people in West African Cameroon, suffocated when a giant bubble of naturally occurring carbon dioxide erupted from Lake Nyos and displaced the available oxygen in the immediate area. 

These cattle were asphyxi- ated by an enormous bubble of carbon dioxide that welled up from the depths of Lake Nyos,... 

Speculations about the role of hydrates in disasters such as the Piper Alpha platform (Boniface, 1990) or Lake Nyos (Rogers and Yevi, 1996) are characterized as hypotheses that are not discussed in this book. 

Table 3.6. Chemical composition of Lake Nyos water at —200 m (Bernard and Symonds 1989). Reprinted from Marion et al. (2003a) with permission...

Lockwood JP, Rubin M (1989) Origin and age of the Lake Nyos maar, Cameroon. J Volcanol Geotherm Res 39 117-124 Lopez-Archilla AI, Marin I, Amils R (2001) Microbial community composition and ecology of an acidic aquatic environment the Tinto River, Spain. Microb Ecol 41 20-35... 

On August 15, 1984, a cloud of deadly gas burst from Lake Monoun in Cameroon, a country in western Africa. Thirty-seven people died from suffocation. Two years later, on August 21, 1986, Lake Nyos, a larger and deeper lake, ejected a full cubic kilometre of the same gas. The gas travelled silently into neighbouring villages, killing 1700 people and thousands of livestock. What was this toxic gas ... 

Lake Nyos and Lake Monoun both sit in volcanic craters. The lakes are hazardous because of their volcanic origin, even though both volcanoes are dormant. Volcanoes are vents through Earth s crust. They carry magma, a mixture of molten rock and dissolved gases, to the surface of Earth. When magma rises to Earth s surface in volcanoes, the pressure is decreased. The gases come out of solution and expand. 

Scientists believe that the tragedies at Lake Nyos and Lake Monoun were caused by a disruption of the water layers, perhaps triggered by a landslide, an earthquake, or even a strong wind. Lower carbonated water was suddenly released into the upper water. As it moved up to the surface, the pressure on the gas decreased while the temperature increased. As a result, the carbon dioxide gas rapidly bubbled out of solution. At Lake Nyos, the sudden release of the lower lake water into the upper layers caused a plume of water and gas to rise high into the air. 

It sinks to the ground and displaces the oxygenated air we need to breathe. The invisible, odourless carbon dioxide that was released from Lake Nyos and Lake Monoun settled on the ground. It travelled rapidly down the slopes into populated regions. People quickly became unconscious and died of suffocation. 

An important example of the consequences of a large C02 release occurred in 1986. Lake Nyos is a crater lake in Cameroon in west central Africa. In 1986, this lake belched a large cloud of carbon dioxide that settle in the region around the lake. More than 1500 people and 3000 head of livestock were killed in the C02 blanket. 

Another interesting result of carbon dioxide solubility in water is that it constitutes the basis for the phenomenon of spontaneous and violent liberation of dissolved C02 to the atmosphere in a stratified lake, as in the case of Lake Nyos in Cameroon mentioned above (see Section 6.1.3). When dissolved C02 seeps from a hydrothermal vent into a stratified lake, the pressure and low temperature favor the dissolution and saturation in the lower strata of the lake. Because of its high solubility, more than five volumes of C02 can dissolve in one volume of water. As for any other gas, however, its solubility depends on temperature and pressure, making the... 

Since 1986 the scientists studying Lake Nyos and nearby Lake Monoun have observed a rapid recharging of the C02 levels in the deep waters of these lakes, causing concern that another deadly gas release could occur at any time. Apparently the only way to prevent such a disaster is to pump away the C02-charged deep water in the two lakes. Scientists at a conference to study this problem in 1994 recommended such a solution, but it has not yet been funded by Cameroon. ... 

Le Guern, F., Tazieff, H. (1989) Lake Nyos. J. Volcanol. Geotherm. Res. 39 (special issue). 

Freeth SJ, Kling GW, Kusakabe M, et al. (1990) Conclusions from the lake Nyos disaster. Nature 348 201. Kling GW, Evans WC, Tuttle ML, and Tanyileke G (1994) Degassing of lake Nyos. Nature 368 405—406. Sigurdsson HS (1988) Gas bursts from Cameroon crater lakes A new natural hazard. Disasters 12 131-146. 

Evans, W.C., Kling, G.W., Tuttle, M.L., Tanyileke, G. White, L.D. (1993) Gas buildup in Lake Nyos, Cameroon the recharge process and its consequences. 

Schenker, F., and Dietrich, V. J. (1986) The Lake Nyos gas catastrophe (Cameroon) a magmatological interpretation, Schweiz. Mineral. 

Rice, A. (2000) Rollover in volcanic crater lakes a possible cause for Lake Nyos type disasters. J. Volcan. Geotherm, Res. 97, 233-239. 

Disaster struck swiftly and without warning. On August 21, 1986, Lake Nyos in Cameroon, a small nation on the west coast of Africa, suddenly belched a dense cloud of carbon dioxide. Speeding down a river valley, the cloud asphyxiated over 1700 people and many livestock. 

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