As you know, natural gas methane practically does not dissolve in water and does not interact with water. Methane is sometimes called "bog gas" because it accumulates at the bottom of swamps. Methane and water molecules contain hydrogen atoms and, under special conditions, can form so-called hydrogen bonds. This happens at low temperatures and enormous pressures that exist at the bottom of the seas and oceans. Even in the tropics, at a depth of 1500 meters, the water temperature does not exceed three degrees Celsius, sometimes it can be below zero. At the bottom of seas and oceans, water and methane molecules form the so-called gas hydrate, which resembles porous ice. As soon as the temperature rises or the pressure drops, the gas hydrate decomposes into pure methane and water.
Lost Cities
Methane is formed in nature not only at a "slow" rate in the thickness of organic deposits, but also at an accelerated rate - due to a chemical reaction between hydrogen and carbon dioxide released from the Earth's mantle. This global process, previously not included in the carbon cycle in nature, was discovered relatively recently.
As it turned out, "fast" methane is squeezed out to the surface of the oceans in the zones of powerful compression, which occurs due to the shift of oceanic and continental plates. This is observed off the west coast of North America. The formation of inorganic methane was found in huge quantities at the bottom of the Atlantic Ocean.
In 2000, scientists made an important discovery: between Africa and North America, hydrothermal fields, called "Lost Cities", were discovered on the ocean floor.
For example, one of them, stretched at a depth of 800 meters, has several dozen huge columns (up to 60 meters in height) made of limestone. Here, in addition to inorganic methane, other hydrocarbon compounds are formed.
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Christopher Columbus's strange observation
During the Spanish expedition to discover the shortest sea route to India, Christopher Columbus wrote that he was observing "boiling water" on the surface of the sea, as well as a "pillar of fire" that appeared from nowhere! It was in the area of the notorious Bermuda Triangle in the Atlantic Ocean. The mystery of the observed phenomena remained for many centuries. And only in our time has a clue emerged. Most likely, the great navigator observed a powerful exit to the surface of methane and saw a torch of burning gas in the air, which may have been ignited by a lightning strike. It is possible that the mysterious cases of the disappearance of ships and aircraft in this area are explained by the presence of giant deposits of gas hydrates at the bottom of the sea. During periods of increased tectonic activity, the bottom rock heats up here, as a result of which the masses of gas hydrates decompose,emit methane, which rushes to the surface and bursts into the atmosphere in a giant column!
In the north and south
Today, scientists are showing an active interest in gas hydrates that lie at the bottom of the northern and southern seas. According to the German professor Hans Falenkamp from the University of Dortmund (Department of Environmental Technologies), the reserves of gas hydrates on our planet "are estimated by geologists to be equal in volume to all the reserves of oil, natural gas and coal explored to date!"
Huge deposits of gas hydrates have been found on the steep slopes of seamounts at depths ranging from 300 to 1000 meters. It is relatively shallow, but it is dangerous to “touch” the slopes, since underwater landslides with unpredictable consequences are possible. However, there are already quite real and economically profitable projects for the extraction of gas hydrates from the bottom of the seas and oceans.
The author of one of these projects, the German scientist Heiko Jurgen Schultz, proposed to lower a large pipe to the bottom of the sea to the gas hydrate deposits, into which a pipe of a smaller diameter is inserted. Hot water is pumped to the bottom along the smaller pipe, which "melts" the gas hydrate deposits, after which the released methane enters the large pipe and rises to the surface. One cubic meter of gas hydrates will give 164 cubic meters of pure methane to the surface!
Germany has long shown interest in samples of gas hydrates lying off the coast of the United States, and is actively working with them. German scientists have learned to store them in special refrigerators at minus 27 degrees Celsius. According to German experts, about half of all carbon on earth is contained in gas hydrates!
Methane hydrate deposit on the seabed off the west coast of Canada
It is clear that the development of gas hydrate deposits and their subsequent extraction exacerbate the problem of global ecology, since the release of huge amounts of methane from the oceans and seas can cause a dramatic climate change.
Baikal treasures
In recent years, scientists of various specialties have begun to actively study Lake Baikal with the help of Mir deep-sea vehicles. The diving program also included environmental monitoring of water in the area of river confluence, on the banks of which there are industrial enterprises, and the study of the structure of the lake bottom, as well as bottom rocks, which will make it possible to clarify the history of the origin and development of Lake Baikal.
As before, in the summer of 2009, the “international scientific expedition“Mira”on Lake Baikal worked on the lake. Two deep-sea vehicles with researchers, transported by the motor ship "Akademik Koptyug" and the floating platform "Metropolia", sank to the bottom of Lake Baikal. The immersion in the area of the mud volcano St. Petersburg (South Lake Basin) brought a sensation: significant deposits of gas hydrates were discovered and even about 5 kilograms of this substance were raised to the surface. At the same time, gas hydrates were found on the surface of the sediments, and not under them.
Dive preparation
The first samples of these valuable deposits were discovered in 2000, and in 2005, at a depth of 1400 meters, scientists saw a gas torch 900 meters high! And in the same area there were deposits of gas hydrates. Working at the bottom for about 10 hours, the staff of Nikolai Granin (head of the laboratory of hydrology and hydrophysics of the Limnological Institute of the Siberian Branch of the Russian Academy of Sciences) observed numerous methane outflows from sedimentary rocks. At the same time, the hydronauts tried to lift the gas hydrate plate to the surface with the mechanical “hand” of the “Mir”, but at a depth of 150 meters they saw how the plate “exploded”!
Deep-sea vehicle “ Mir-2 ”
And here is a recent message: near the Malniy mud volcano from a depth of 1300 meters, as part of the second technological expedition "Baikal Hydrates 2009", it was still possible to take samples of gas hydrates. But Alexander Egorov, a participant in the Mir-2 dive, sees the main meaning of the discovery in the fact that the results of work on Lake Baikal make it possible to study the processes taking place in the World Ocean “in a kind of natural laboratory”.
Source: Secrets of the XX century, №41, October 2009, Alexander UDACHIN