Two million inhabitants of the African shores are in danger of death at any moment because of the emanations of carbon dioxide and methane.
Three Lakes hide in the depths true bombs. Lakes Nyos in Cameroon and Monoun contain huge amounts of carbon dioxide. Under certain conditions, it can cause strong outbursts of gas, real explosions, accompanied by toxic fumes.
Also, Lake Kivu, located on the border between Rwanda and the Democratic Republic of Congo, stored in its depths both carbon dioxide and methane.
The release gases into the atmosphere would simply look death among residents on its banks. Kivu, to not become a “killer lake“, as they are considered Nyos and Monoun, should be subjected to the exploitation of methane gas for conversion into electricity.
On the night of August 21, 1986, within a radius of 30 kilometers around Lake Nyos, there was a real disaster, which left more than 1,800 people and thousands of animals have died.
No one can explain why, even more so because, two years ago, a phenomenon equally enigmatic hit Cameroon bereaved homes on the shores of Lake Monoun.
The inhabitants of the shores of Lake Kivu live their life living conditions of uncertainty gas to “smoldering” in deep water.
Where, including scientists have come to wonder if Cameroon lakes are simply doomed. After a long investigation, which has mobilized many researchers, the mystery has been elucidated: the release huge amounts of carbon dioxide from the depths of asphyxiation caused lakes surrounding residents, while they slept. Thus was born the legend “killer lakes“.
Methane of Lake Kivu, untapped energy source
Lake Kivu hides in its depths, about 300 billion cubic meters of carbon dioxide, that is a thousand times more than Lake Nyos contained when the gas was released into the atmosphere! Moreover, it is known since the 1940s that the waters of Lake Kivu stores tens of billions of cubic meters of methane. This gas is an invaluable source of energy for the two neighboring countries, but which is not yet exploited. On the other hand, the same energy resource represents a threat “death” for the two million people who live on the banks of the lake.
“A lake can not contain an unlimited amount of gas in its depths. When the gas pressure in the water accumulated at a certain depth, the pressure exceeds the amount of water from the surface, in the depths of the lake form gas bubbles. This sudden climb to the surface and dissolved gas train infested waters, releasing the form of fountains, huge amounts of gas into the atmosphere.
To make a comparison, on a smaller scale, it is the same phenomenon that occurs when you open a bottle of champagne, said Michel Halbwachs, professor of physics at the University of Savoie and specialist in African lakes, which organized in this regard, field missions, funded by the European Community.
Same researcher says that methane plays a very important role in the event of an explosion. “Without the presence of methane, gaseous explosion risk would be negligible. Methane is basically the detonator and the detonator might trigger much earlier than we might expect“said Michel Halbwachs.
The amount of gas increases spectacular
Michel Halbwachs compared the results obtained from field missions conducted between 2002 and 2004 with those in 1970 and found that in only 30 years, the amount of methane from the depths increased by 15 percent. Additional quantities of methane will cause the pressure to grow and reach a saturation point. When the lake can not retained for a long time, the gas in its depths.
The researchers sought to understand the reason for this spectacular growth of methane inside the lake, in a short time. They released several assumptions that are today in the debate. “The first hypothesis is related to population growth on the banks of the lake and the intensification of agriculture. Disposal of organic waste in the lake could encourage the growth of aquatic organisms, “said Martin Schmid, a researcher at Water Research Institute in Switzerland.
When the organ–organisms die, their often-com–making takes place on the bottom, some bacteria converting organic matter into methane, which would accelerate the formation of natural gas.
The gas was supplemented because of a sardine?
Some researchers believe that agricultural practices and urbanization are not only responsible for the proliferation of organisms in the lake. An alternative explanation, which sparked numerous debates so far, is entering the stage of “Limnothrissa miodon“, an organic sardine of Lake Tanganica. It was introduced in Lake Kivu in the late ‘50, to remedy the absence of fish production. The rapid development of Sardine – about 4,000 tons are caught annually – would upset the balance of the ecosystem of the lake. “Before the introduction of the sardine, there were no fish in Lake Kivu to feed with zooplankton.
With the arrival of the sardine, we estimate that the biomass of zooplankton decreased tenfold in 50 years, “said Francois Darchambeau, researcher at the Laboratory of Freshwater Ecology, University of Namur, Belgium. Zooplankton feeds with phytoplankton. In the absence of predator, proliferated phytoplankton sediment on the bottom of the lake without getting into the food chain. Therefore, it would be more organic matter available to produce methane.
After Darchambeau opinion, “this phenomenon can not yet explain himself, a significant increase in the available methane from Lake Kivu.”
Lake can kill at any time
However, Lake Kivu is not necessarily doomed to turn into a “lake killer” because a political initiative, which began in April 2007.
Then, Rwanda and DRC have agreed to revive a project of exploitation of methane from Lake Kivu to get electricity. This action is intended to not let lake to reach saturation, while reducing potential risks to the population. Thus, Rwanda and would provide electricity for decades. Would reduce the need to use sources of wood for this purpose, the region is undergoing a process of intense deforestation.
After two deadly gaseous eruptions that occurred in 1984 and 1986 studies showed that both “killer lakes” Nyos and Monoun, reconstituted CO2 content from below very quickly. Thus, a new disaster risk increases from day to day. Public access, on an area of 30 kilometers around Lake Nyos is now banned.
To prevent a possible explosion, Michael Halbwachs installed between 2001-2003, a preventive system of artificial water degazaj. The water is aspirated and discarded from below the surface. In this way, the carbon dioxide is released into the atmosphere, without this constituting an environmental problem: the amount of CO2 is lower than that resulting from local traffic. Unlike Lake Kivu, the two “killer lakes” does not contain exploitable methane.