An analysis of the fan-shaped sediment “Danube Fan”, located to the northwest of the Black Sea, reveals that this bizarre area appears to be still in its ice age even though it has ended some 12,000 years. before.
Hydrate is a solid compound of gas and water with an ice-like structure at low temperatures and high pressures. Compounds of methane and water, called methane hydrates, are found especially on many fringes of the ocean – as well as in the Black Sea.
In addition to being able to be used as an energy source, methane hydrate deposits are being studied for their stability, as they can dissolve under changes in temperature and pressure. In addition to the release of methane, this can also affect the stability of the ocean floor.
According to a recent study published in Earth and Planetary Science Letters (EPSL), an analysis of the fan-shaped sediment region “Danube Fan”, located northwest of the Black Sea, reveals this strange region appears to be is still in the ice age though it ended about 12,000 years ago.
Specifically, during a six-week expedition with the German research vessel METEOR in the fall of 2017, a team of scientists from MARUM and GEOMAR studied a methane hydrate mine in the fan-shaped sediment “Danube Fan”. is located northwest of the Black Sea bottom.
During the journey, as part of the SUGAR III cooperation project “Underwater Hydrate Resources” co-sponsored by BMWi and BMBF, the hydrate fields were drilled with the mobile marine bed drilling equipment MARUM-MeBo200.
The results of the studies, now published in the international journal Earth and Planetary Science Letters, have provided scientists with new insights into changes in hydrate stability.
“Based on data from previous expeditions, we have selected two areas to study, one area namely methane hydrate and free methane that coexist at an altitude of 50 to 150 meters in the stable zone. hydrates and another area are soil and gas, ”explained Professor Dr. Gerhard Bohrmann, head of the expedition from MARUM and co-author of the study. “For exploration, we used the drill MARUM-MeBo200 and broke all previous depth records with a maximum depth of nearly 145 meters.”
In addition to sample collection, scientists are able for the first time to perform detailed on-site temperature measurements of the amount of hydrates in marine sediments.
Typically, the method most widely used in the world to predict the existence and quantitatively evaluate gas hydrates (gas hydrates) in marine sediments is seismic, from which the so-called “mirror” is obtained. simulated bottom reflection ”(BSR) as an indicator of this facility.
Dr. Michael Riedel from GEOMAR, lead author of the study, said: “However, our work has demonstrated for the first time that the BSR approach is ineffective with the Black Sea. In our opinion, the hydrate stability boundary has come closer to surface warmer conditions, but the free methane gas, always found at this lower edge, has yet to rise with it. “
According to Dr. Michael Riedel, this may be due to the low permeability of the sediments, which means that methane is still “trapped” below and can only rise very slowly below. strength by itself.
The stable hydrate zone here is similar to the surface hydrate stabilization zone at the end of the last ice age. This profound system seems only to perceive the end of the era of reconciliation and struggle.
This finding will help in future climate modeling, according to Science Alert. Science has shown that there are huge volumes of hydrate deposits underneath the Arctic, and how they react to rising global temperatures in the coming years will have a significant effect on the climate.
It is known that methane hydrate is a major source of energy reserves for mankind. However, warming climates can destabilize hydrates. Methane, a potential greenhouse gas, will escape into the atmosphere and could even accelerate climate change.
Hydrate acts as a layer of cement to fill the voids between the grains of sand, stabilizing the seabed. If the methane hydrate decomposes, the stability of the seabed will decrease due to the loss of cement and pressures through the pores. In the worst case, landslides on the ocean floor can cause severe tsunamis.