A limnic eruption, you say. Is that some new form of envronmental disaster that we should be aware of?
Everyone is very familiar with the phrase “volcanic eruption”, but not very many people are familiar with the term “limnic eruption.” This is because this event is extremely rare. A limnic eruption refers to a lake overturn, an occurrence in which the bottom of the lake suffers an eruption of carbon dioxide. When this happens, it results in the loss of life of any people or animals who are in the vicinity because the carbon dioxide takes the oxygen out of the surrounding air. It can also cause a tsunami in the lake because of the extremely high levels of carbon dioxide.
In order for a limnic eruption to take place in a lake, certain conditions must exist. The main one is that there needs to be a high level of gas in the lake, so much so that scientists say it is saturated with gas. It is possible that the carbon dioxide comes from a volcano beneath the surface or from the decomposition of a tremendous amount of organic material on the bottom.
You can think of a limnic eruption as similar to what happens when you shake a can of soda pop and then pop the top. The pressure causes the liquid to come pouring out of the can. In a lake of water there is much higher pressure at the bottom of the lake than there is closer to the surface. In very deep lakes, there may be large amounts of carbon dioxide dissolved in the waters close to the bottom. The water at this level is much cooler which keeps the carbon dioxide in a dissolved state. However, once the temperature starts to rise, it evaporates into a gaseous form and becomes more volatile.
Once the water temperature of a lake is such that it has reached the saturation point in the amount of carbon dioxide it contains, the lake is in a very critical stage and has the potential of erupting. The only thing lacking at this point is a trigger, which could be a rain or wind storm or an earthquake in another region. Such a trigger brings the water saturated in carbon dioxide much closer to the surface where it cannot be contained by the decreased pressure. The result is a column of gas called a limnic eruption in the lake.
It is very rare for this event to take place because of the necessity of the presence of carbon dioxide. In regions where there are no volcanoes, there is no possibility of it occurring at all. In temperate lakes, the water pressure is too low to maintain the carbon dioxide in a soluble state and as it nears the surface of the water it escapes into the air naturally. A lake also has to be incredibly deep in order to maintain the level of pressure needed for the conditions to materialize close to the bottom.
During a limnic eruption a large cloud of carbon dioxide forms above the surface of the water in a lake. This then sinks to the ground because it is heavier than air and soaks up all the breathable air in the surrounding area. In addition to making it very difficult to breathe under these conditions, the presence of excess amounts of carbon dioxide tends to change bodily fluids into acid inside the body, causing carbon dioxide poisoning, which is also deadly.
