Where in the Ocean Floor is Methane Gas Coming From?
The methane gas that the researchers are concerned about are the gases trapped inside ocean floor sedimentations. These trapped gases are supposed to remain stable at 0°C below the freezing point of water, under water depths of beyond 500 meters.
The trapped chemical compounds are gas hydrates that filled the porous gaps of sedimentations which practically cemented the latter into ice-formations with zero permeability. These ice formations are called permafrosts and they contain large amounts of trapped methane gas.
If temperature and pressures under these water depths remain unchanged or stable, the permafrost sedimentation remains stable and the methane gas stays inside them.The ocean floor will continue to form layers of tightly sealed permafrosts.
However, if scientists are telling us that methane gas is seeping out from Arctic sea-beds, then it draws us to an understanding that the effects of global warming has increased the temperature and pressure below depths of 500 meters. Simply stated, the warmth of the ocean temperature has reached levels capable of melting the gas hydrates, which were formerly maintained at 0°C below the freezing point of water. Rising methane gas hazards on the oceans's surface are indications that permafrost below the ocean depths have thawed off.
What are Gas Hydrates?
Gas hydrates are natural gasses which include methane and they combine with water, under pressures already beyond the freezing point of 0°C. This combination of gas and water will take the form of crystalline solids similar to ice particles and are called gas hydrates or clathrates. They are commonly found underneath a permanently frozen land mostly in the polar areas and around 500 meters deep below the Earth’s continental margin.
Other gasses that form into gas hydrates are hydrogen sulfide, carbon dioxide, and numerous hydrocarbons with low-carbon number.
Environmental Impact of Thawed Out Permafrost
The possibility of global warming effects, thawing out multitudes of frozen layers of permafrosts will result to the release of high concentrations of methane and other gasses. By this alone, we could imagine the degree of temperature capable of thawing out permafrost that is sustained at 0°C below the freezing point of water.
There are also risks involved in setting up drilling platforms, pipelines and wells in the sea-floor as great amounts of gasses are unleashed. In addition, since most methane in gas hydrates are biogenic in nature or bacteria generated methane, the simultaneous release of these biogenic gasses poses possible environmental risks. Unexplained explosions around these drilling sites have taken place and scientists are not discounting the possibility of these methane gas hazards as the probable causes.
In sea water, methane gas reacts with the oxygen content of the water and will form into carbonic acid that will contribute in large amounts to the ocean’s acidification. Extreme levels of acidification pose grave threats to marine biodiversity.
On the other hand these gas hydrates could be considered as a source of fuel instead of methane gas hazards. Worldwide occurrences of gas hydrates, could account for 1x104 gigatons of carbon at the least, based on conservative estimates. This is said to be twice the figure of carbon found in all of the Earth's fossil fuels.
Despite this possible advantage, we have to consider that any increase in methane gas emissions is still considered as increase in greenhouse gases, and this could only worsen global warming effects.