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Jessy P

on 27 August 2014

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Before and After a Limnic Eruption
What Causes Limnic Eruptions?
How Do Limnic Eruptions Impact People?
Lake Nyos
The Effects
Why They Occur
Apart from major natural disasters setting off this rare event, even intense winds can trigger limnic activity in the lake. The pressure causes the CO2 to form into a column, which sucks up the water at the bottom of the lake and releases the carbon dioxide. Then all the combined CO2 rises upwards and outwards. It pushes the water away from it as it erupts, causing a minor tsunami. Even the tsunami is lethal because it is saturated with carbon dioxide. The explosion is quite loud, and the eruption can reach prodigious heights. So in general, limnic eruptions occur when a lake becomes saturated with CO2. The physical attributes of a lake that is vulnerable to limnic activity include it being a very deep lake, as well as it being close to triggers such as volcanoes.
The CO2 that is found in lakes builds up overtime. The water becomes saturated with carbon dioxide mainly because of the flow of lava from nearby volcanic activity. The lake would not be temperate but mostly cool, because it is easier for carbon dioxide to dissolve in places where there is higher pressure, such as at the bottom of lakes. Even though the CO2 disintegrates more readily in cooler temperatures, a larger amount of carbon dioxide is released if the lake is more heated. Limnic Eruptions are triggered by other natural disasters such as earthquakes, volcanic eruptions, wind storms, rain storms and other natural disasters that disturbs nearby land. When one or more of these events occur, it causes the CO2 as well as the water to become very unstable.
Friday, August 29, 2014
By Jessica Pinto
What is a Limnic Eruption?
A Limnic Eruption, which is also referred to as a lake overturn, is a very rare natural disaster. It is when a large amount of dissolved carbon dioxide, is released from under a lake. This is a natural disaster because the carbon dioxide, known as CO2, which rises up out of the lake and disperses across surrounding land, causes major asphyxiation to any life forms that breathe it in. There have been only 2 known occurrences of this disaster, and scientists are working on ways to prevent any more incident like this.

When a limnic eruption occurs, it drastically effects everything around it. The CO2 causes asphyxiation to all living organisms nearby. To plants and animals, the carbon dioxide simply suffocates them, which is commonly fatal. This proves to be a problem for people who provide for themselves using these animals and plants, because depending on how far the CO2 spreads, it can potentially take out all livestock. Carbon dioxide also has extreme effects to humans. The CO2 causes immediate asphyxiation because the CO2 due to fact that there is very little oxygen among the carbon dioxide. The lack of oxygen in the air during that time is because carbon dioxide is quite heavy, therefore it sinks towards the ground while pushing breathable air upwards. This is why some say that during a limnic eruption you should try and get to higher ground, so that you have breathe in less CO2. Breathing in carbon dioxide is mostly fatal, but for the few survivors, they were knocked out by the intensity. Many survivors of a limnic eruption have been found covered in numerous blisters, which were caused by pressure ulcers. These are formed due to the low levels of oxygen in the blood of those who were suffocated by the CO2. Carbon dioxide also makes the human body fluids acidic, causing CO2 poisoning. Another way carbon dioxide effects humans is by causing sensory hallucinations. Survivors have reported that they smelled rotten egg and gunpowder whilst in the CO2. Scientists have proven that this is because of high concentrations. Survivors have also claimed to have felt a sudden warmth before passing out. Since the CO2 is released at such a cold temperature, it can also cause frostbite to the victims.
Known Occurrences
How Many Limnic Eruptions Have Happened?
To date, a rare natural disaster like this has happened only twice. The first was at Lake Monoun at Cameroon. This happened in 1984 and resulted in the asphyxiation and death of 38 people. The second was much deadlier. It occurred around the same area, but was in Lake Nyos in 1986. It was much more lethal because the carbon dioxide had spread to 0.08 cubic kilometres, which is approximately 80 million cubic metres. This caused the death of around 1 700 people and 3 500 livestock. Although there hasn't been an eruption yet, at Lake Kivu scientists have found a very large amount of dissolved carbon dioxide in the water. Scientists are looking into ways to reduce the chances of the lake erupting.
Prevention/Reducing Of Effects
How Do You Stop A Limnic Eruption?
There are very few ways to reduce the effect or prevent a limnic eruption. A simple way would be to own a gas mask if you live around those areas, but depending on how their lifestyle is the people who live around those lakes may not be able to afford it. Although this may be a smart idea, it is only a way to reduce the effects. The only way to really prevent it is by pumping the carbon dioxide from the lake. A team led by French scientist Michel Halbwachs has been working on this, and have been quite successful. They experimented with siphons, which are pipes, and placed them in a certain way to degas the lake in a controlled manner. The pipe is placed vertically with the top slightly above the surface. The water that has been saturated with carbon dioxide is transported through the pipe and comes out the upper end. Due to the low pressure, the CO2 comes out of solution, taking the form of bubbles. It is released in a way that is non-lethal to the humans and livestock around it. This is a good way to degas the lake because it also recycles the water once the carbon dioxide comes out of it. Although the water has to be voluntarily pumped to get the flow working, other than that the pipes work independently. The pumping of the pipes is fuelled by the natural buoyancy of the carbon dioxide bubbles. They draw the water upwards at high speeds, causing it to resemble a large fountain. The de-gasifying water becomes a self-sustaining pump because it draws water in and out of the pipe. This is currently the only way to prevent Limnic Eruptions.
Although Limnic Eruptions are not very common and have only occurred twice, they are very serious and cause numerous problems to those who are at risk of them. Scientists are working together to find more ways to prevent or reduce the effects of they natural disasters, but they haven't come up with anything revolutionary yet. Judging by the rapid expansion of technology recently, it is almost certain that scientists will come up with more ways to prevent these serious natural disasters. In general, limnic eruptions only happen in tropical areas, in deep and stable lakes. Temperate lakes usually turn over according to seasons, so this is also an aid in getting the lake to erupt. Limnic eruptions effect many people and places, and are occur due to several reasons that all contribute to the explosion of the lake.
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