Posts
Electronic
translation from the Russian
Tomsk University scientists : under-water permafrost on the East Siberian Arctic shelf is
deteriorating faster than previously thought
Ученые
ТПУ: подводная мерзлота на Восточно-Сибирском
арктическом шельфе деградирует быстрее,
чем считалось ранее
9
August, 2017
The rate of vertical degradation of under-water permafrost on the East
Siberian Arctic shelf over the last 30 years, is reaching 18 cm per year
(on average, 14 cm per year), which is much higher than previously thought.
The results, obtained from the large-scale study of the state of
underwater permafrost throughout the entire history of research in the
Russian Arctic, but the Arctic as a whole, have been shared by scientists of
Tomsk Polytechnic University in a scientific paper published in the
journal Nature Communications.
Photo: Arctic
expedition of Russian and Swedish scientists SWERUS-C3
In July, scientists TPU published a scientific article in the journal Nature Communications (IF 12,1; Q1).
Sponsored
polytechnics were scientists from Russia and Sweden.
According
to scientists, previously it was thought that the main part of the
submarine permafrost of the shelf seas of the Eastern Arctic (MVA) —
the wide and shallow shelf of the World ocean is continuous, which
excludes the possibility of destabilization digitalguy giant pool of
methane hydrates. According to the model estimates of the
intergovernmental panel of climate change (Intergovernmental Panel on
Climate Change, IPCC), it is assumed that before the end of the 21st
century, the degradation of submarine permafrost in the Eastern
Arctic seas may not exceed several meters, and for the formation of
through taliks (zones of degradation — the complete thawing of the
underwater permafrost) will require hundreds, if not thousands of
years, which eliminates the possibility of a massive release of
methane (CH4) is the second most important greenhouse gas — from
seabed sediments MVA in the water column-atmosphere due to the
destruction of hydrates. Based on these conclusions, based on
simulation without well-founded formulation of boundary and initial
conditions and no validation by field data obtained by scientists of
TPU in cooperation with the leading scientists of the Siberian Arctic
consortium, created on a scientific platform, TPU, potential climatic
role of the offshore MBA in the context of the possibility of a
massive release of methane into the water column-atmosphere IPCC is
regarded as insignificant and excluded from consideration. The
article shows that this is not so.
On the basis of re-drilling four wells, made by the permafrost Institute SB RAS in 1982-1983, scientists have shown that the vertical velocity of the degradation of submarine permafrost in the last 30 years reach 18 cm per year (mean 14 cm per year), which is approximately an order of magnitude higher than was previously assumed.
"Progressive
degradation (thawing) of underwater permafrost leads to the formation
of gazovikami channels, the presence of which was predicted on the
basis of our first results in MBA in 2000-2010, and mathematical
modeling, — says the first author, Professor, Department of Geology
and mineral exploration TPU Natalia
Shakhova.
— On the basis of new results obtained by means of complex
biogeochemical, geophysical, and geological studies carried out in
2011-2016 years, we come to the conclusion that in some parts of the
East Siberian shelf, the roof of the submarine permafrost has already
reached the depth of the zone of stability of hydrates, the
destruction of which may lead to a massive bubble of methane
emissions. Such phenomena have been discovered and documented, our
team of authors for many years on the shallow and deep shelf of the
MVA. And the proof of the existence of the upward movement of
the gas front through the thick rain with a speed of five metres per
year can also serve as a confirmation of our hypothesis about the
destabilization of hydrates as the main candidate to explain the
anomalously high concentrations of methane in water and air on the
East Siberian shelf, which was published in 2010 in the
journal Science.
According to our results, published in Nature Geoscience, Science
and Philosophical
Transactions,
Royal Society, the magnitude of bubble flux of CH4 from sediments to
water in an MBA can vary from milligrams to hundreds of grams per
square meter per day, depending on the state of underwater
permafrost, which leads to an increase in the concentration of
atmospheric CH4 in the near-water layer up to values 2-4 times higher
than the background concentration measured on our planet".
Natalia
Shakhova notes that these results have been confirmed in the
expedition, organized and executed in a MVA in 2016, together with
scientists from the Pacific Oceanological Institute Feb RAS (POI),
with the participation of the Institute of Oceanology, RAS (ioras)
and the Institute of atmospheric physics RAS (IAP RAS); relevant
publications are expected in 2018.
"In addition, together with scientists from ioras us a new mechanism of acceleration of methane bubble release from the bottom sediments into the water (and into the atmosphere) due to the ice vypaivanija the stamukha in shallow water, and the icebergs on the outer shelf of the MVA, resulting in formation of a furrow, reaching the gas front.
The
size of these furrows reach many kilometers, at a depth of
vypaivanija to 4-6 meters, which in many places is accompanied by
bubble emissions of CH4 in the water column-atmosphere", —
says the head of the International laboratory for the study of carbon
in Arctic seas, TPU, corresponding member of RAS Igor
Semiletov.
As
noted, in turn, Natalia Shakhova implementation of recently adopted
by the Russian Government plan of actions for implementation of the
development Strategy of the Arctic zone of the Russian Federation and
national security for the period up to 2020 is largely dependent on
understanding the processes and factors that can help or hinder the
progressive development of the Arctic region.
"Currently,
the level of this understanding is mainly provided by
hydro-meteorological research. However, without regard to their
connection with the complex biogeochemical and geological processes
occurring as a result of the degradation of submarine and coastal
permafrost, as shown in work published in Nature
Communications,
it is impossible to assess the risks arising from the development of
the Arctic shelf", says Natalia Shakhova.
For
example, for safe drilling of the resource need to have knowledge on
the situation, structure and condition of submerged permafrost, the
places potentially dangerous in the context of a possible massive and
even catastrophic release of methane due to an explosion of hydrates
(such cases are known in the Pechora sea, the Gulf of Mexico, the
Straits of Dmitri Laptev to the East Siberian sea). In this context,
it is crucial to continue a
comprehensive study TPU
scientists with colleagues from leading institutions and universities
of Russia and other countries. To raise the technological level of
works on the study of the state of underwater permafrost and Arctic
shelf of Russia, the implementation of which in 2018 is scheduled
expedition, the scientists find it expedient to modify the latest
version of
the submersible TPU,
which has been tested in expeditions to the seas of the Eastern
Arctic in 2016.
"The results of our study provide fundamentally new knowledge about the mechanism of the processes responsible for changing the state of underwater permafrost on the East Siberian shelf, which according to various estimates accounts for up to 80 % or more of an entire submarine permafrost of the Northern hemisphere, under which there are huge reserves of hydrocarbons in the form of hydrates, oil-free gas.
In
the future, based on these data will be reviewed and revised
approaches to the study of the state of underwater permafrost and its
mathematical modeling, which is extremely important to reduce
geohazard arising from the conduct of exploratory and production
drilling. However, there still remain many unresolved questions that
will be addressed by future research our research team,"
concludes Igor Semiletov.
Help:
Read
more research the
Siberian Arctic consortium,
created on a scientific platform TPU can be found
here: https://tpu.ru/research/fields/arctic; http://poisknews.runnet.ru/theme/publications/20163/;http://www.ras.ru/news/shownews.aspx?id=e65b47df-836f-4717-acbd-5193b971a5f7; http://xn--m1afn.xn--p1ai/ru/node/2201.
Note,
in 2014 Tomsk Polytechnic University has established the
international laboratory of carbon in Arctic seas, which became a
scientific platform to unite scientific and technical potential of
higher schools and leading institutes of the Russian Academy of
Sciences, and the creation of an international consortium for the
exploration of the seas of the Arctic, composed of representatives of
14 universities and scientific centers of Russia, Sweden, the
Netherlands, UK and USA. Research group under the guidance of
professors of Tomsk Polytechnic University Igor Semiletov and Natalia
Shakhova won to carry out these research grants of the Russian
Government and the Russian science Foundation. The results of the
study make an important contribution to the understanding of the
functioning of the Arctic climate system. The latest publication in
Nature Communications confirms the leading positions of Russian
scientists in this priority direction of the Earth Sciences, and
continues a series of publications in top journals including Science
and Nature group of journals.
Underwater permafrost on the Arctic shelf melting faster than expected
9
August, 2017
Russian
and Swedish researchers have published a research survey showing that
the underwater permafrost layer on the Eastern Siberian
continental shelf is melting faster than expected, the press
service of the Tomsk Polytechnic University told.
"In
1982-1983, the Permafrost Research Institute of the Siberian
Branch of the Russian Academy of Sciences drilled four
wells, and based on this data we found that the rate of vertical
underwater permafrost degradation in the area has gone up to
18 centimeters per year (14 centimeters on average) in the
past 30 years, which is ten times faster than expected,"
the press service said.
It
was believed that the permafrost layer on the sea shelf in the
eastern Arctic was mostly solid, which would not allow the
possibility of methane emissions from under the ice. It was
assumed that the melting of the permafrost would not exceed
several meters before the end of the 21st century, and
that it would take from hundreds to thousands of years
for it to melt through.
"Based
on the new results obtained by comprehensive
biogeochemical, geophysical and geological research made
in 2011-2016, we can conclude that in some areas of the
Eastern Siberian shelf the permafrost layer has thinned and reached
the stability zone of hydrates, the destruction of which
might lead to massive emissions of methane bubbles,"
Natalya Shakhova, professor at the university's Geology and
Exploration Department, was quoted as saying.
According
to the survey, the volume of methane emissions from the
bottom sediment in eastern Arctic seas can vary from milligrams
to dozens to hundreds of grams per a square meter per
day, depending on the condition of the permafrost layer.
This leads to a two to four times increase in atmospheric
methane in the above-water layer.
Researchers
also discovered another reason for the increase in methane
emissions into the water and the air: in shallow waters,
icebergs and large ice floes plow through the sea bottom making
trenches 4-6 meters deep. They reach the gas layers and release
methane.
