Limnic+Eruption

A **limnic eruption**, also known as **lake overturn**, occurs when //carbon dioxide// (or in some cases //methane//) erupts from a lake killingmm instantly any animal or human being neirby.



=How does a limnic eruption happen?=

A limnic eruption can only happen on indirectly volcanically active ground since the carbon dioxide (or in some cases methane) are created underneath the Earth mantle. The cool lake-bottom traps the carbon dioxide under the tons of water masses and due to the growing amount of gas the pressure is built up until it erupts, causing a small tsunami as a side-effect. Because carbon dioxide is heavier than air it stays near ground, moving with the speed of 50 kilometres per hour.

The elements needed for the lake eruption are:
 * an underwater gas source
 * high pressure
 * low temperatures
 * naturally low overturn system

Basically limnic eruption works like a soda bottle. When one opens a soda bottle, is there a low hiss, and if bottle is shaken the carbon dioxide comes from the bottom, foaming up. If the soda is cold the carbon dioxide dissolves better - maximizing the effect. [|Soda bottle effect]

=When has a limnic reaction happened?= Human reseachers have encountered a limnic eruption only twice, though they might have occured throughout history. They are extremely hard to trace since the gas is hardly visible and kills instantly. The first known limnic eruption happened 1984 at lake Monoun in Cameroon killing 37 people in nearby villages. Only two years later another limniac eruption took place at other Cameroonian lake, Lake Nyos killing 1,800 locals.

Resent study also shows marks of a lake overturn at Lake Kivu, located between Democratic Republic of the Congo and Rwanda, every 1,000 years.

Islandic Volcano researcher Haraldrur Sigurdsson was the first one to discover the reason behind the silent death. After identifying his water samples from Lake Nyos to be full of carbon dioxide he realised that the lake is actually a time bomb. Because the leak of carbon dioxide is continuous the happenings are likely to take part again. However, there has been a plan in desaturating the lakes.

=What could be done?=

Reducing the risk of carbon dioxide (and in the case of Lake Kivu, methane) eruption is possible and not too hard, even. As seen in the picture on the left side, a whole the plan is really simple. In 2001 a huge tube was erected from the bottom of the lakes Nyos and Monoun up to the surface. At start, a pump sucks the carbon dioxided water. When the pressure lessens whilst going closer to the lake cover the gas starts bubbling, because of which the foggy cloud created by the CO2 and water sprays up to the air.

Problem with the process is funding. With only one pipe it takes over thirty years to get the lakes clean of the gas. All the time new CO2 leaks from the ground and gets stuck onto the lake bottom. As shown in the picture, there are two chances. Other being paying for the pumps, the other a new limnic eruption.

= = = Is a limnic eruption always a bad thing? =

Even though you would think a limnic eruption is always a disaster there is a good side to it. There is so much carbon dioxide and methane trapped under certain lakes (namely Lake Kivu) that could be turned into a power source. For example by placing a long tube that reaches the bottom of the lake to lead all the gas into an electric power plant nearby. In this way electricity can be generated saving all that wood been cut and burnt.

Made by Meri Djerf and Atiti Iduozee


 * Sources:**

Reader's Digest: Kun luonto näyttää voimansa Wikipedia: Limnic eruption Limnic eruption: http://mivo-sys.tripod.com/limnic.html