For a lake to undergo a limnic eruption, the water must be nearly saturated with gas. CO2 was the primary component in the two observed cases (Lake Nyos and Lake Monoun). In Lake Kivu, scientists are concerned about the concentrations of methane gas as well. CO2 may originate from volcanic gas emitted from under the lake or from decomposition of organic material. Before a lake is saturated, it behaves like an unopened carbonated beverage (e.g., a soft drink): the CO2 is dissolved in the water. In both the lake and the soft drink, CO2 dissolves much more readily at higher pressure (Henry's law). This is why bubbles in a can of soda form only after the can is opened; when the pressure is released, the CO2 comes out of solution. In the case of lakes, the bottom is at a much higher pressure; the deeper it is, the higher the pressure is at the bottom. Therefore, huge amounts of CO2 can be dissolved in large, deep lakes. CO2 also dissolves more readily in cooler water, such as that found at a lake bottom. A small rise in water temperature can lead to the release of a large amount of CO2.