Rwandan lake runs risk of turning into freshwater time bomb

November 17th, 2009 - 5:43 pm ICT by ANI  

Washington, November 17 (ANI): Scientists have expressed their fears that Lake Kivu, the freshwater lake system bordering Rwanda and the Republic of Congo, runs the risk of turning into a freshwater time bomb because of a dangerous level of carbon dioxide and methane gas.

In a region prone to volcanic and seismic activity, the fragility of Lake Kivu is a serious matter.

Compounding the precarious situation is the presence of approximately 2 million people, many of them refugees, living along the north end of the lake.

An international group of researchers will meet January 13-15 at a conference in Gisenyi, Rwanda, to grapple with the problem of Lake Kivu.

“Most scientists are fairly in agreement that the lake is pretty stable; it’s not as if its going to come bursting out tomorrow,” said Anthony Vodacek, conference organizer and associate professor at RIT’s Chester F. Carlson Center for Imaging Science.

“But in such a tectonically and volcanically active area, you can’t tell what’s going to happen,” he added.

One of the problems with Lake Kivu is that the 1,600-foot deep lake never breathes.

The tropical climate helps stagnate the layers of the lake, which never mix or turn over. In contrast, fluctuating temperatures in colder climates help circulate lake water and prevent gas build up.

Lake Kivu is different from both temperate and other tropical lakes because warm saline springs, arising from ground water percolating through the hot fractured lava and ash, further stabilize the lake.

A number of catalysts could destabilize the gas resting at the bottom of Lake Kivu.

It could be an earthquake, a volcanic explosion, a landslide or even the methane mining that has recently united Rwandan and Congolese interests.

Vodacek likens the contained pressure in the lake to a bottle of carbonated soda or champagne.

“In the lake, you have the carbon dioxide on the bottom and 300 meters of water on top of that, which is the cap,” he said. “That’s the pressure that holds it. The gas is dissolved in water,” he added.

When the cap is removed, bubbles form and rise to the surface. More bubbles form and create a column that drags the water and the gas up to the surface in a chain reaction.

Through his own research, Vodacek plans to simulate the circulation of Lake Kivu.

Modeling the circulation patterns above the layers of carbon dioxide and methane will help determine the energy required to disrupt the gas and cause Lake Kivu to explode. (ANI)

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