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Thu, Feb

Methane hydrate dissociation off Spitsbergen not caused by climate change

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Methane hydrates, also known as flammable ice, occur in many regions of the oceans. But only under high pressure and cold temperatures the product of methane and water forms a solid compound. If the pressure is too low or the temperature is too high, the hydrates decompose, and the methane is released as gas from the sea floor into the water column. Spitsbergen has been experiencing severe outgassing for several years. Does the methane originate from decomposed methane hydrates? What is the cause of the dissociation of the hydrates? Warming due to climate change or other, natural processes? An international team of scientists has now been able to answer this question, which has been published in the international journal Nature Communications.

Methane hydrates, also known as flammable ice, occur in many regions of the oceans. But only under high pressure and cold temperatures the product of methane and water forms a solid compound. If the pressure is too low or the temperature is too high, the hydrates decompose, and the methane is released as gas from the sea floor into the water column. Spitsbergen has been experiencing severe outgassing for several years. Does the methane originate from decomposed methane hydrates? What is the cause of the dissociation of the hydrates? Warming due to climate change or other, natural processes? An international team of scientists has now been able to answer this question, which has been published in the international journal Nature Communications.

“Our investigations show that uplift of the sea floor in this region caused by the melting of the ice masses since the end of the last ice age is probably the reason for the dissolution of methane hydrate, which is already ongoing for several thousand years,” explains Prof. Dr. Klaus Wallmann, first author of the study by GEOMAR Helmholtz Centre for Ocean Research Kiel. “The region has raised more than the sea level has risen, causing a pressure relief, so that the methane hydrates dissociate at the stability limit," Wallmann continues.

Continue reading at GEOMAR - Helmholtz Centre for Ocean Research Kiel

Photo: White methane hydrate layers traverse the sediments.

CREDITS: MARUM - Zentrum für Marine Umweltwissenschaften, Universität Bremen; G. Bohrmann