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Research Vessel Encounters Giant Methane Seep in Arctic Waters

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Image courtesy TPU

By The Maritime Executive 2019-10-08 21:42:55

Researchers from Tomsk Polytechnic University reported Monday that they have found an "unusually powerful" methane seep in the remote East Siberian Sea. 

The team - comprised of TPU faculty and scientists from other Russian research institutions - is on a mission to study the environmental impact of melting permafrost. Subsea permafrost is similar to permafrost on shore, but underwater; it is found in shallow-water areas of the Arctic continental shelf, including areas of the Beaufort Sea and waters of the East Siberian Sea. 

Just like permafrost on shore, subsea permafrost is a reservoir for methane gas and gas hydrates. As it thaws, this methane is released into the water, and at shallow depths it may reach the surface as perceptible bubbles. 

In order to study the effects of a warming climate on subsea permafrost, the team aboard the research vessel Akademik Mstislav Keldysh has been examining the area around Bennett Island, the largest of the De Long Island group in the northern portion of the East Siberian Sea. At a position roughly 150 nm to the east of the island, they spotted a large methane seep using hydroacoustics. 

"It's one thing to [find] this phenomenon with the help of special instruments, and it’s completely different to see the methane emission to the surface of the water with your own eyes. No matter how accurate the equipment showing the coordinates of the sip, to find in the sea waves the place where the gas breaks into the atmosphere is more complicated than finding a needle in a haystack," said Sergey Nikiforov, a spokesman for TPU on the expedition. "On the right side of the Keldysh, they saw a spot of emerald color against the background of dark water. Approaching it, scientists were able to observe how gas rises from the black depths of the sea to the surface with thousands of bubble filaments."

The seep measured about five square meters in area on the surface of the sea, and the team reported that water "boiling" with methane bubbles could be "scooped up with buckets." The air in the vicinity registered a methane concentration of up to 16 ppm, about nine times the normal amount, according to expedition leader Prof. Igor Semiletov - the highest ever registered for a seep at sea.  

As a practical matter, Prof. Semiletov warns that degradation of subsea permafrost in the Eastern Arctic could have implications for safety - in particular, for any future offshore oil and gas development. "The formation of the Yamal craters is an illustration of what can happen at any time in [these] vast waters, including licensed areas of Rosneft and Gazprom. Our team is able to develop scientifically based approaches that will minimize the geo-risks associated with the progressive degradation of underwater permafrost and massive emissions of bubble methane," he said in an interview last year.