Major Methane Releases at Laptev Megaflare Spot
Global Methane Tracking,
23 July, 2014
The SWERUS-C3 (Oden) expedition continues to update methane findings of the past several days. The ship's current location is in the Laptev Sea, searching for methane plumes and rechecking stations visited in past expeditions by Semiletov and Shakhova.
The
circled area on the map is the area of the methane emissions
addressed below.
Source:
http://oden.geo.su.se/map/
Use
Google Chrome for website.
What
is being found is surprising and sobering. As Ulf Hedman, Science
Coordinator, Swedish Polar Research Secretariat reported yesterday,
they have
found at least one "megaflare" of methane release
from the Laptev Sea floor into
the armosphere.
In
his words, "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."
Source:
http://polar.se/en/blogg/mega-flare/
Örjan
Gustafsson, Stockholm University, commented, "The discovery was
made
while the icebreaker Oden crosscut the Laptev Sea along a depth
gradient from
1000m to just 100m 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."
Source:
http://www.su.se/english/research/leading-research-areas/science/
swerus-c3-first-observations-of-methane-release-from-arctic-ocean-hydrates-1.
198540
swerus-c3-first-observations-of-methane-release-from-arctic-ocean-hydrates-1.
198540
Hedman
posted this image to illustrate the rise of, and the saturation of
methane in
the ocean at one location which seems to be at about 62
meters in depth.
Hedman's comments about this search and discovery were: "Back and forth, back
and forth. We are now on the way to station 22. Back and forth.
Indications of flares and the mid-water sonar goes red. We throw everything
we got in the water and turn on all ship system to maximum for logging data."
Indications of flares and the mid-water sonar goes red. We throw everything
we got in the water and turn on all ship system to maximum for logging data."
So
what are the initial findings?
According
to Örjan Gustafsson, Stockholm University, "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
methane saturation levels were the big surprise, "results of
preliminary
analyses of seawater samples pointed towards levels of
dissolved methane 10-50
times higher than background levels."
What
is causing the seeps to increase?
"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.”
Source:
http://www.su.se/english/research/leading-research-areas/science/swerus-
c3-first-observations-of-methane-release-from-arctic-ocean-hydrates-1.198540
That
subsurface Atlantic water is accompanied by Laptev Sea surface
temperatures as high as 6.9 C, as reported by Oden over the last few days.
temperatures as high as 6.9 C, as reported by Oden over the last few days.
How
large an area of methane release is witnessed by the expedition?
Enough
that it is a significant source emitting from several areas in
the megaflare.
"We mapped out an area of several kilometers where bubbles were filling the
"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 60-70m depth), a likely consequence
of the thawing subsea permafrost."
of the thawing subsea permafrost."
We
have gained solid science data on a major methane source that is
entering the
atmosphere form the Laptev, and it will be interesting
to observe how many more
will be found in the coming days. If this is
further documented, we are witnessing
the further degradation of
subsea permafrost with real global climate implications.
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