Exploding lakes are a terrible natural phenomena and very serious environmental problem.
These lakes are capable of killing thousands, even millions of people and animals living in the region.
In 1986 an awful tragedy occurred when Lake Nyos, in the volcanic region of Cameroon, suddenly released a cloud of carbon dioxide into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages.
Scientists were at the time not aware of the exploding lake phenomenon although the first event happened in 1984, when 37 people near Lake Monoun died suddenly.
Lake Nyos is an active crater lake that formed by an eruption about 5 centuries ago.
Nyos is located about 95 km from Lake Monoum. Together these two are the only two volcanic lakes in the world other than Lake Kivu that contain large amounts of CO2.
After many years of study the science community has come to an agreement that the origin of CO2 within Lake Nyos is due to CO2 that rises from volcanic activity.
This CO2 is then dissolved into groundwaters and transferred to the lake resulting in the slow saturation of the hypolimnion.
Cameroon's exploding lakes are a unique example of this phenomenon, where CO2 is trapped in the bottom water of deep volcanic craters.
The gas stays at the bottom of the lake, held down by the pressure of the overlying water.
But eventually, CO2 gas can start to bubble up to the top of the lake, which reduces the water pressure that usually holds the gas down.
Lake Nyos was responsible for the death of 1,700 people and 3,500 livestockWhen this happens, the gas from the bottom of the lake can vent with exploding force, creating a suffocating cloud that can kill people and animals in low-lying areas.
In order to prevent Lake Nyos from exploding again, an international team of scientists and engineers has developed and implemented a program to artificially remove gas from the lake through piping.
USGS scientists initially advised on the project and have long monitored gas levels in the lake to determine whether this removal has been successful. They'll also update devices monitoring gas levels in nearby Lake Monoun, another exploding lake, where CO2 has now been completely removed as part of the same project.
In 2001, a French engineering firm installed pipes that reached the very bottom of the lakes. Pumps initially push some of the lower water upward, releasing water pressure and allowing CO2 gas bubbles to form. Once bubbles form, the gas naturally flows up and out of the pipe at a controlled rate.
This technique has successfully resulted in the complete degassing of Cameroon's Lake Monoun, which now poses no risk of gas release. Much of the gas in Lake Nyos has been removed as well, but degassing will continue for several more years before the CO2 is completely gone.
Lake KivuThe USGS continues to monitor water conditions at these two lakes. The probes that measure the dissolved gas pressure are built at USGS, and are permanently installed in the lakes. After a decade of use, the most recent probes now need to be replaced.
Unfortunately, this problem is not yet solved. According to recent reports, the lake now contains twice as much carbon dioxide as was released during the explosion. Earlier attempts to siphon off the gas had to be abandoned for financial reasons.
If Lake Kivu were to explode, over two million people and thousands of animals who live around it would be in danger.
Can we really say we lack financial resources to prevent these defenseless living beings from a possible horrifying death?
Print Page
Hiç yorum yok:
Yorum Gönder