On August 21, 1986, a deadly cloud rose from Lake Nyos in Cameroon, killing nearly everyone in its path. The day after, 1700 people were dead and the lake, normally blue, was red. The disaster was determined to be caused by an outburst of carbon dioxide. CO2 accumulates in the lake’s deep bottom levels, where it remains in solution, undisturbed by the currents that temperature changes would bring further from the equator and kept dissolved by pressure. Over time, the bottom of the lake becomes so saturated that a small trigger, whether that be a rapid change in temperature, a landslide, or something else, could release the carbon dioxide out of the solution, bubbling up to the surface in gas form. This is what happened that day in 1986. A tall column of water shot out of the lake, and the gas cloud, being heavier than oxygen, displaced the air, asphyxiating almost everyone in its path. The red color was due to iron-rich water from the depths reaching the surface and oxidizing.
A similar disaster on a smaller scale had happened two years earlier in another lake in Cameroon, Lake Monoun, killing 37, but nothing similar had ever been recorded, and few believed that a deadly cloud of carbon dioxide could be the culprit.
Today, pumps are installed in Lake Nyos to prevent the disaster from reoccurring: CO2-rich water from the depths is pumped high enough that the gas starts bubbling to the surface of its own accord, thus safely releasing it in smaller increments. Funding to provide enough pumps to make both lakes—as well as a third lake that may also have mounting CO2-levels in the depths—safe, is still incomplete.
dailymeh posted this on July 15, 2011
