Photo: John & Mel Kots (flickr)
Have you heard of the exploding lakes in central Africa?
Three exploding lakes are known, each with certain key features. They are very deep, they don’t undergo seasonal water turnovers like most lakes, and each lake sits atop an active volcano.
Beneath the lake, molten rock belches carbon dioxide [CO2] into the water. The intense pressure at the bottom of the deep lake causes gases to be absorbed into the water, like carbonation in a can of soda. The water takes up gas until it can’t absorb any more. Then any trigger, like an earthquake, landslide, or heavy rainstorm and KABOOM, the lake explodes like soda from a shaken can.
Explosions release huge clouds of gas that envelop the surrounding area. An explosion in 1986 released enough CO2 to fill ten football stadiums, suffocating seventeen-hundred people, and thousands of livestock in Cameroon.
In Lake Kivu, bacteria in the lake convert the CO2 into methane, which is highly flammable and could trigger an even more dangerous lake explosion. Alternatively, extracting the fifty-five billion cubic meters of methane from Lake Kivu could provide electricity for Rwanda for four-hundred years.
The good news is that scientists might be able to “de-gas” these killer lakes, and hopefully prevent future explosions. By inserting long tubes down to the lake bottom, the gas-filled water siphons up to the surface, venting the dangerous gas. However, many siphons are needed for each lake, making the cost of de-gassing extremely high. The benefit may outway the cost, as for the millions of people living near these lakes, the danger is still very real.