Previously undescribed<\/strong><\/h2>\n![\"Joel](\"https:\/\/site.uit.no\/cage\/wp-content\/uploads\/2018\/12\/Joel-200x300.jpg\")
<\/a>Associate professor Joel Johnson, visiting scholar at CAGE.<\/figcaption><\/figure>\n\u201cCurrent geophysical data from the flank of this ultraslow spreading ridge shows that the Arctic environment is ideal for this type of methane production. \u201c says Joel Johnson associate professor at the University of New Hampshire (USA), lead author, and visiting scholar at CAGE.<\/p>\n
This is a previously undescribed process of hydrate formation; most of the known methane hydrates in the world are fueled by methane from the decomposition of organic matter.<\/strong><\/p>\n\u201cIt is estimated that up to 15 000 gigatonnes of carbon may be stored in the form of hydrates in the ocean floor, but this estimate is not accounting for abiotic methane. So there is probably much more.\u201d says co-author and CAGE director J\u00fcrgen Mienert.<\/p>\n
Life on Mars?<\/strong><\/h2>\nNASA has recently discovered traces of methane on the surface of Mars, which led to speculations that there once was life on our neighboring planet. But an abiotic origin cannot be ruled out yet.<\/p>\n
On Earth it forms\u00a0through a process called serpentinization.<\/p>\n
\u201cSerpentinization occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor. These only form in slow to ultraslow spreading seafloor crust. The optimal temperature range for serpentinization of ocean crust is 200 \u2013 350 degrees Celsius.\u201d says Johnson.<\/p>\n
Methane produced by serpentinization can escape through cracks and faults, and end up at the ocean floor. But in the Knipovich Ridge it is trapped as gas hydrate in the sediments. How is it possible that relatively warm gas becomes this icy substance?<\/p>\n
\u201cIn other known settings the abiotic methane escapes into the ocean, where it potentially influences ocean chemistry. But if the pressure is high enough, and the subseafloor temperature is cold enough, the gas gets trapped in a hydrate structure below the sea floor. This is the case at Knipovich Ridge, where sediments cap the ocean crust at water depths up to 2000 meters. \u201c says Johnson.<\/p>\n
<\/p>\n
Stable for two million years<\/strong><\/h2>\n![\"Scientists](\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\")
<\/a>At ultra slow spreading ridges plates spread away from each other very slowly so that the mantle is\u00a0exposed. Knipovich Ridge has a spread rate of less than 1.5 cm per year. A new class of these ridges was discovered as late as 2003 by scientists at Woods Hole Oceanographic Institution. Illustration: Dr. Henry J. B. Dick , WHOI\/nsf.gov<\/figcaption><\/figure>\nAnother peculiarity about this ridge is that because it is so slowly spreading, it is covered in sediments deposited by fast moving ocean currents of the Fram Strait. The sediments contain the hydrate reservoir, and have been doing so for about 2 million years.<\/p>\n
\u201c This is a relatively young ocean ridge, close to the continental margin. It is covered with sediments that were deposited in a geologically speaking short time period \u2013during the last two to three million years. These sediments help keep the methane trapped in the sea floor.\u201d says Stefan B\u00fcnz of CAGE, also a co-author on the paper.<\/p>\n
B\u00fcnz says that there are many places in the Arctic Ocean with a similar tectonic setting as the Knipovich ridge, suggesting that similar gas hydrate systems may be trapping this type of methane along the more than 1000 km long Gakkel Ridge of the central Arctic Ocean.<\/p>\n
The Geology paper states that such active tectonic environments may not only provide an additional source of methane for gas hydrate, but serve as a newly identified and stable tectonic setting for the long-term storage of methane carbon in deep-marine sediments.<\/p>\n
Need to drill<\/strong><\/h2>\n<\/a>Samples of the gas hydrates will provide more knowledge on abiotic methane. But they need to be drilled, as they are 140 meters under the ocean floor. Photo: Wikimedia Commons.<\/figcaption><\/figure>\nThe reservoir was identified using CAGE\u2019s high resolution 3D seismic technology aboard research ressel Helmer Hanssen. Now the authors of the paper wish to sample the hydrates 140 meters below the ocean floor, and decipher their gas composition.<\/p>\n
Knipovich Ridge is the most promising location on the planet where such samples can be taken, and one of the two locations where sampling of gas hydrates from abiotic methane is possible.<\/p>\n
\u201c We think that the processes that created this abiotic methane have been very active in the past. It is however not a very active site for methane release today. But hydrates under the sediment, enable us to take a closer look at the creation of abiotic methane through the gas composition of previously formed hydrate.\u201d says J\u00fcrgen Mienert who is exploring possibilities for a drilling campaign along ultra-slow spreading Arctic ridges in the future.<\/p>\n
<\/p>\n
[table id=1 \/]<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
A reservoir of abiotic methane has been discovered in the Arctic Ocean. This means that … <\/p>\n
<\/a>\u201cCurrent geophysical data from the flank of this ultraslow spreading ridge shows that the Arctic environment is ideal for this type of methane production. \u201c says Joel Johnson associate professor at the University of New Hampshire (USA), lead author, and visiting scholar at CAGE.<\/p>\n
This is a previously undescribed process of hydrate formation; most of the known methane hydrates in the world are fueled by methane from the decomposition of organic matter.<\/strong><\/p>\n \u201cIt is estimated that up to 15 000 gigatonnes of carbon may be stored in the form of hydrates in the ocean floor, but this estimate is not accounting for abiotic methane. So there is probably much more.\u201d says co-author and CAGE director J\u00fcrgen Mienert.<\/p>\n NASA has recently discovered traces of methane on the surface of Mars, which led to speculations that there once was life on our neighboring planet. But an abiotic origin cannot be ruled out yet.<\/p>\n On Earth it forms\u00a0through a process called serpentinization.<\/p>\n \u201cSerpentinization occurs when seawater reacts with hot mantle rocks exhumed along large faults within the seafloor. These only form in slow to ultraslow spreading seafloor crust. The optimal temperature range for serpentinization of ocean crust is 200 \u2013 350 degrees Celsius.\u201d says Johnson.<\/p>\n Methane produced by serpentinization can escape through cracks and faults, and end up at the ocean floor. But in the Knipovich Ridge it is trapped as gas hydrate in the sediments. How is it possible that relatively warm gas becomes this icy substance?<\/p>\n \u201cIn other known settings the abiotic methane escapes into the ocean, where it potentially influences ocean chemistry. But if the pressure is high enough, and the subseafloor temperature is cold enough, the gas gets trapped in a hydrate structure below the sea floor. This is the case at Knipovich Ridge, where sediments cap the ocean crust at water depths up to 2000 meters. \u201c says Johnson.<\/p>\n <\/p>\n Another peculiarity about this ridge is that because it is so slowly spreading, it is covered in sediments deposited by fast moving ocean currents of the Fram Strait. The sediments contain the hydrate reservoir, and have been doing so for about 2 million years.<\/p>\n \u201c This is a relatively young ocean ridge, close to the continental margin. It is covered with sediments that were deposited in a geologically speaking short time period \u2013during the last two to three million years. These sediments help keep the methane trapped in the sea floor.\u201d says Stefan B\u00fcnz of CAGE, also a co-author on the paper.<\/p>\n B\u00fcnz says that there are many places in the Arctic Ocean with a similar tectonic setting as the Knipovich ridge, suggesting that similar gas hydrate systems may be trapping this type of methane along the more than 1000 km long Gakkel Ridge of the central Arctic Ocean.<\/p>\n The Geology paper states that such active tectonic environments may not only provide an additional source of methane for gas hydrate, but serve as a newly identified and stable tectonic setting for the long-term storage of methane carbon in deep-marine sediments.<\/p>\n The reservoir was identified using CAGE\u2019s high resolution 3D seismic technology aboard research ressel Helmer Hanssen. Now the authors of the paper wish to sample the hydrates 140 meters below the ocean floor, and decipher their gas composition.<\/p>\n Knipovich Ridge is the most promising location on the planet where such samples can be taken, and one of the two locations where sampling of gas hydrates from abiotic methane is possible.<\/p>\n \u201c We think that the processes that created this abiotic methane have been very active in the past. It is however not a very active site for methane release today. But hydrates under the sediment, enable us to take a closer look at the creation of abiotic methane through the gas composition of previously formed hydrate.\u201d says J\u00fcrgen Mienert who is exploring possibilities for a drilling campaign along ultra-slow spreading Arctic ridges in the future.<\/p>\n <\/p>\n [table id=1 \/]<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" A reservoir of abiotic methane has been discovered in the Arctic Ocean. This means that … <\/p>\nLife on Mars?<\/strong><\/h2>\n
Stable for two million years<\/strong><\/h2>\n
![\"Scientists](\"https:\/\/site.uit.no\/cage\/wp-content\/uploads\/2018\/12\/ultra-slow-spreading-gakkel-ridge.jpg\")
<\/a>Need to drill<\/strong><\/h2>\n
![\"Wikimedia](\"https:\/\/site.uit.no\/cage\/wp-content\/uploads\/2018\/12\/gasshydrate.jpg\")
<\/a>