Limnic eruption

Nyos Lake

Monoun

Limnic eruption diagram

Cow killed by Lake Nyos gasses

LakeKivu satellite

Limnic eruption, also known as a lake overturn, is a rare but catastrophic natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock, and humans. This phenomenon has been recorded in only a few lakes around the world, most notably in Lake Nyos and Lake Monoun in Cameroon, Africa. The cause of limnic eruptions is not entirely understood, but they are believed to be triggered by geological or volcanic activity that disturbs the layers of water in lakes with high concentrations of dissolved CO2.

Causes and Mechanism

A limnic eruption occurs when CO2, dissolved in deep lake waters under high pressure, is suddenly released. This can happen due to a disturbance such as an earthquake, volcanic eruption, or even a landslide. In normal conditions, lakes are stratified into layers, with colder, denser water sitting at the bottom. When these layers are disturbed, the deep water rich in CO2 can rapidly rise to the surface, releasing the gas into the atmosphere. The rapid release of CO2 can also create a displacement of water, potentially causing a tsunami.

Historical Incidents

The most well-known incidents of limnic eruptions occurred at Lake Nyos in 1986 and Lake Monoun in 1984. The Lake Nyos disaster resulted in the deaths of over 1,700 people and thousands of animals. After these events, scientists installed degassing tubes in these lakes to safely release the gas and prevent future eruptions.

Prevention and Mitigation

Preventive measures for limnic eruptions include the installation of degassing systems that allow the safe, gradual release of dissolved CO2 from the bottom layers of the lake to the surface. Monitoring of gas concentrations and the stability of lake stratification is also crucial for early warning systems.

Impact

The impact of a limnic eruption extends beyond the immediate threat to life. It can cause long-term environmental damage, disrupt local economies, and displace communities. The psychological effects on survivors and the loss of livestock and agriculture can also be devastating.

See Also

• Lake Nyos
• Lake Monoun
• Carbon dioxide
• Natural disaster