Scientists can't say for sure if the volatile mixture at the bottom of the lake will remain still for another 1,000 years or someday explode without warning. 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 Jan. 13-15 in Gisenyi, Rwanda, to grapple with the problem of Lake Kivu. Addressing the lake as a whole system is a new concept for the researchers, who will bring their expertise in volcanology, tectonics and limnology to the problem. Their goal is to prioritize research activities and improve communication between the North American, European and African collaborators.
"Most scientists are fairly in agreement that the lake is pretty stable; it's not as if its going to come bursting out tomorrow. But in such a tectonically and volcanically active area, you can't tell what's going to happen," says Anthony Vodacek, an associate professor of Imaging Science at RIT who is organizing the meeting of researchers.
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. Scientists at the workshop will consider how these spring inputs may vary over time under changing climates and volcanic activity.
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.
Close calls occurred in 2008 when an earthquake occurred near the lake and in 2002 when a volcanic eruption destroyed parts of Goma in the Democratic Republic of Congo, only 11 miles north of Lake Kivu. Although scientists were alarmed, neither event sufficiently disturbed the gas.
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 says. "That's the pressure that holds it. The gas is dissolved in water."
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.
"The question is, and what's really unknown, is how explosive is that?" Vodacek says.