Metaanijääesiintyminä

Metaanijääesiintyminä, known in English as methane clathrates or methane hydrates, are crystalline solid structures in which a gas molecule, typically methane, is trapped within a cage of water molecules. These formations occur in environments where both methane and water are present under specific conditions of high pressure and low temperature. The most common locations for these deposits are along continental margins on the ocean floor, where the overlying water pressure is sufficient and temperatures are near freezing. They can also be found in permafrost regions, both on land and under the Arctic Ocean.

The formation process involves methane gas dissolving into pore water and then crystallizing into a hydrate lattice. This lattice structure is not a chemical bond but rather a physical encapsulation. While methane is the most prevalent gas, other gases like ethane and carbon dioxide can also form clathrates. These deposits represent a vast reservoir of carbon, estimated to contain more carbon than all the world's fossil fuel reserves combined.

The stability of methane clathrates is sensitive to changes in pressure and temperature. For example, a decrease in pressure or an increase in temperature can cause the clathrates to dissociate, releasing the trapped methane gas. This dissociation is a subject of significant scientific interest and concern due to the potential for methane release into the atmosphere. Methane is a potent greenhouse gas, and large-scale dissociation could potentially contribute to climate change. Research is ongoing to better understand the extent and stability of these deposits and the implications of their potential dissociation.