"Vast methane plumes escaping from the seafloor" discovered in Siberian Arctic Sea

by FishOutOfWater, DailyKos, July 28, 2014

 

Vast methane plumes have been discovered boiling up from the seafloor of the Arctic ocean on the continental slope of the Laptev Sea by a dream team of international scientists. Over the last decade a warming tongue of Atlantic ocean water has been flowing along the Siberian Arctic ocean's continental slope destabilizing methane ice, hypothesize the team of Swedish, Russian and American scientists. The research team will take a series of measurements across the Siberian seas to attempt to understand and quantify the methane release and predict the effect of this powerful greenhouse gas on global and Arctic warming. Because the Siberian Arctic contains vast stores of methane ices and organic carbon that may be perturbed by the warming waters and Arctic climate, Arctic ocean and Siberian sea methane release could accelerate and intensify Arctic and global warming.

Attribution: http://polar.se/en/blogg/mega-flare/

 

Methane megaflare on Laptev Sea slope at around 62m depth. "We are “sniffing” methane. We see the bubbles on video from the camera mounted on the CTD or the Multicorer. All analysis tells the signs. We are in a Mega flare. We see it in the water column we read it above the surface an we follow it up high into the sky with radars and lasers. We see it mixed in the air and carried away with the winds. Methane in the air." Ulf Hedman, Science Coordinator, Swedish Polar Research Secretariat

SWERUS expedition preliminary cruise plan and study areas of Leg 1 and 2. EEZ=Exclusive Economic Zone; LR=Lomonosov Ridge; MR=Mendeleev Ridge; HC=Herald Canyon; NSI=New Siberian Islands.

 

Örjan Gustafsson's blog post of this discovery gave me the chills.

So, what have we found in the first couple of days of methane-focused studies? 

(1) Our first observations of elevated methane levels, about ten times higher than in background seawater, were documented already as we climbed up the steep continental slope at stations in 500 and 250 m depth. This was somewhat of a surprise. While there has been much speculation of the vulnerability of regular marine hydrates (frozen methane formed due to high p and low T) along the Arctic rim, very few actual observations of methane releases due to collapsing Arctic upper slope marine hydrates have been made.

It has recently been documented that a tongue of relatively varm Atlantic water, with a core at depths of 200–600 m may have warmed up some in recent years. As this Atlantic water, the last remnants of the Gulf Stream, propagates eastward along the upper slope of  the East Siberian margin, our SWERUS-C3 program is hypothesizing that this heating may lead to destabilization of upper portion of the slope methane hydrates. This may be what we now for the first time are observing.

(2) Using the mid-water sonar, we mapped out an area of several kilometers where bubbles were filling the water column from depths of 200-500 m. During the preceding 48 h we have performed station work in two areas on the shallow shelf with depths of 60-70 m where we discovered over 100 new methane seep sites. SWERUS-C3 researchers have on earlier expeditions documented extensive venting of methane from the subsea system to the atmosphere over the East Siberian Arctic Shelf. On this Oden expedition we have gathered a strong team to assess these methane releases in greater detail than ever before to substantially improve our collective understanding of the methane sources and the functioning of the system. This is information that is crucial if we are to be able to provide scientific estimations of how these methane releases may develop in the future.

Here is the SWERUS press release on this discovery.

Methane bubbles discovered on Laptev continental slope of Arctic ocean.

Just a week into the sampling program and SWERUS-C3 scientists have discovered vast methane plumes escaping from the seafloor of the Laptev continental slope. These early glimpses of what may be in store for a warming Arctic Ocean could help scientists project the future releases of the strong greenhouse gas methane from the Arctic Ocean. 

”This was somewhat of a surprise,” writes chief scientist Örjan Gustafsson, Stockholm University, in his latest blog entry. He speculates that the leaking methane from the seafloor of the continental slope may have its origins in collapsing “methane hydrates,” clusters of methane trapped in frozen water due to high pressure and low temperature.

The discovery was made while the icebreaker Oden crosscut the Laptev Sea along a depth gradient from 1000 m to just 100 m following the continental slope upward to reach the shallow waters of the outer Laptev Sea Shelf. By use of acoustic techniques and geochemical analyses of water samples, the scientists found vast methane plumes escaping from the seafloor at depths between 500 m and 150 m. At several places, the methane “bubbles“ even rose to the ocean surface. What’s more, results of preliminary analyses of seawater samples pointed towards levels of dissolved methane 10–50 times higher than background levels.

“While there has been much speculation about the vulnerability of regular marine hydrates along the continental slopes of the Arctic rim, very few actual observations of methane releases due to collapsing marine hydrates on the Arctic slope have been made,” writes Örjan Gustafsson.

Örjan Gustafsson thinks that the mechanism behind the presence of methane seeps at these depths may have something to do with the ”tongue” of relatively warm Atlantic water, presumably intruding across the Arctic Ocean at 200–600 m depths.” Some evidence have shown that this water mass has recently become warmer. As this warm Atlantic water, the last remnants of the Gulf Stream, propagates eastward along the upper slope of the East Siberian margin, it may lead to destabilization of methane hydrates on the upper portion of the slope. This may be what we are now seeing for the first time,” writes Örjan Gustafsson.

SWERUS-C3 scientists could determine the depth from which methane plumes were bubbling up with the help of precise sonar instruments commonly used to map the bottom of the deep ocean and detect gas seeps in the water column. ”We mapped out an area of several kilometers where bubbles were filling the water column at depths of 200 to 500 m,” writes Örjan Gustafsson. Additional observations include the discovery of over 100 new methane seep sites in the shallower waters of the Laptev shelf (at 60–70 m depth), a likely consequence of the thawing subsea permafrost.

 http://www.dailykos.com/story/2014/07/28/1317252/--Vast-methane-plumes-escaping-from-the-seafloor-discovered-in-Siberian-Arctic-Sea

Semiletov & Shakhova have discovered more than 200 sources of methane emissions in the Arctic, Laptev Sea

Methane emission in the Arctic – a possible key to the global warming

by Maria Dunayeva, Voice of Russia, September 18, 2012

Photo: RIA Novosti

Russian scientists have discovered more than 200 sources of methane emissions in the Arctic, particularly in the north of the Laptev Sea. Two of the methane fields exceed 1 kilometer in diameter, said Igor Semiletov, expedition head aboard the Viktor Buinitsky research vessel. Methane emissions in the Arctic have been observed before and are explained by bacterial activity. Head of the ecology department at Moscow State University, Dmitry Zamolodchikov, spoke about the possible consequences in an exclusive interview with the Voice of Russia.

How would you comment on this discovery by Russian scientists?

Different examples of methane emissions in Arctic coastal regions and in the tundra systems have been observed over the last 20 or 30 years. There is really nothing surprising about this. Because, first of all, we are talking about frozen substances and cold conditions in the coastal area, in addition to the water pressure, all of which make perfect conditions for so-called gas hydrates. That is a bond between methane and water, which looks like snow, and is fairly unstable. Gas hydrates can quite easily break and can cause, correspondingly, methane emissions. Methane emerges as a result of bacteria activity in an environment with little oxygen which decomposes organic substances. The tundra has a humid climate, meaning it has the perfect conditions for the methane-producing bacteria. In that sense tundra is the source of methane and these bacteria are active in this region. In other words the Arctic has many mechanisms for production of natural methane. There are many mechanisms that conserve methane, for example gas hydrates. Many of those mechanisms are broken at higher temperatures. Therefore, in some cases, mass emissions of methane can be observed.

What consequences can mass methane emission lead to?

That is a complicated question. Scientists who study this, and there are quite a few of them, follow two opposing opinions. There is the view that it could lead to catastrophic consequences in the nearest future, because the process of methane emission will only grow. Methane is a potent greenhouse gas which will induce higher temperatures and will have the effect of a self-expanding wheel which is rolled down a hill, meaning that the process will go faster and faster. It will threaten our planet with countless disasters and horrible consequences. Yet another group of scientists believes that, because it is a natural process, there are both positive feedbacks that amplify methane emissions and negative feedbacks which lead to the increase of methane absorption. Beside the methane-producing bacteria there are also methanotrophic bacteria. Curiously enough they consume methane during the course of their life, they do so because if we combine methane with oxygen we get energy. In natural ecosystems both types of bacteria are present. The ones that consume methane live where there is enough oxygen, and those who produce methane live where there is little oxygen. It is a hard to know how the balance between synthesis and consumption of methane is reached, because warming in the tundra can reduce humidity in the region, causing methanotrophs. Meaning there are processes which amplify methane production and consumption. It is possible that in the future we will have a situation where balance between production and consumption of methane will be reached.

http://english.ruvr.ru/2012_09_18/Methane-emission-in-the-Arctic-a-possible-key-to-the-global-warming/

Shakhova & Semiletov have discovered spots in the Arctic Ocean where mass emissions of methane can be observed

Methane emissions discovered in Arctic Ocean

Readers, there is a difference between what the scientists found last year and this year.  This year, the spots of methane emissions are larger than one kilometer in diameter.  I am not sure what the photo signifies.  It might be showing the bubbling part next to a sea ice flow, but since there is no caption for the photo, this is just speculation.

Photo: RIA Novosti

Russian scientists have discovered spots in the Arctic Ocean where mass emissions of methane can be observed.

from the Voice of Russia Radio News, September 15, 2012

According to the press-service of the expedition aboard The Viktor Buinitsky research vessel, the diameter of some of the ‘methane fields’ found in the northern part of the Laptev Sea exceeds 1 kilometre.

The new discoveries will help to understand the mechanism of global warming on Earth, experts believe. In their opinion, emissions of methane could have catastrophic consequences for the climate of our planet.

http://english.ruvr.ru/2012_09_15/Methane-emissions-discovered-in-Arctic-Ocean/

"Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea Region," JGR (2012), by Dmitry J. Nicolsky, Vladimir E. Romanovsky, Nicolai Romanovskii, Alexander Lvovich Kholodov, Natalia Shakhova & Igor P. Semiletov; doi:10.1029/2012JF002358

Journal of Geophysical Research, doi:10.1029/2012JF002358

Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea Region

Dmitry J. Nicolsky, Vladimir E. Romanovsky, Nicolai Romanovskii, Alexander Lvovich Kholodov, Natalia Shakhova and Igor P. Semiletov

Key Points

• Review of the underlying assumptions of previous models
• Development of an up-to-date model of sub-sea permafrost in Laptev Sea
• Development of open taliks underneath submerged thaw lakes on the shelf

Abstract

Models of sub-sea permafrost evolution vary significantly in employed physical assumptions regarding the paleo-geographic scenario, geological structure, thermal properties, initial temperature distribution, and geothermal heat flux. This work aims to review the underlying assumptions of these models as well as to incorporate recent findings, and hence develop an up-to-date model of the sub-sea permafrost dynamics at the Laptev Sea shelf. In particular, the sub-sea permafrost model developed here incorporates thermokarst and land-ocean interaction theory, and shows that the sediment salinity and a temperature-based parametrization of the unfrozen water content are critical factors influencing sub-sea permafrost dynamics. From the numerical calculations, we suggest development of open taliks may occur beneath submerged thaw lakes within a large area of the shelf.

Received 24 January 2012; accepted 30 July 2012.

Citation: Nicolsky, D. J., V. E. Romanovsky, N. Romanovskii, A. L. Kholodov, N. Shakhova, and I. P. Semiletov (2012), Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea Region, J. Geophys. Res., doi:10.1029/2012JF002358, in press.

http://www.agu.org/pubs/crossref/pip/2012JF002358.shtml