Ladda ner årsbok 2008 (6,5 MB) - Polarforskningssekretariatet

organizations in Russia, Sweden, UK and
USA (Figure 2). The main vessel H/V Jacob
Smirnitskyi travelled the entire length of the
Siberian coast from Kirkenes, Norway through
the Barents – Kara – Laptev – East Siberian
Seas to Herald Canyon, Chukchi Sea and back
along the outer shelf. This area extending
over 4 000 km is largely unexplored, despite
being one of the largest continental shelf seas
in the world. A second ship sampled the Lena
River and the southeastern Laptev Sea. The
ISSS-08 programme was structured into eight
interlinked and collaborating programmes:
Benthic biology, Biogeochemistry, Geophysics/
seismic, Marine chemistry, Methane, Physical
oceanography, Sedimentology, and Trace
elements and isotopes.
the fieldwork
Observations and sampling of the air made
underway included micrometeorology and
continuous measurements of methane and
carbon dioxide, sampling of air particles
(aerosols) and gas-phase organic compounds.
A seawater intake system was successfully
installed and demonstrated to provide clean
samples for organic substances. Surface seawater
samples were thus frequently collected
while underway along the thousands of kilometres
long route for studies of organic and
inorganic carbon, including methane. A
number of chemical sensors provided realtime
monitoring on the composition of this
surface seawater.
The ship made over 130 stops for extended
at-station sampling (Figure 2). A multitude of
samplers for probing of seawater properties
and collection of seawater and sediments
were deployed at these stations. A second ship
detailed the Lena River and the southeastern
Laptev Sea, including on-land sampling of the
eroding coastal soil.
Release of methane and other
at-sea observations
Significant at-sea findings included the
discovery of new methane seeps and bubble
plume fields in both the Laptev and East
Siberian Sea, several associated with geophysical
gas-chimney structures. These are notable
as the conventional thought has been that
the sub sea permafrost ought to act as a lid
to keep the methane from escaping from the
sediments. The Intergovernmental Panel on
Climate Change (IPCC) points out that release
of methane from the ESAS subsea permafrost
does potentially constitute a substantial positive
feedback to climate warming but IPCC
refrains from making any assessment of
this risk due to the lack of data. The ISSS-08
contributes substantial new observations
on methane actually being released in this
region. It is too early to make any conclusions
of the quantitative magnitude of this methane
release for the atmospheric methane budget. It
is also not yet possible to draw any conclusions
with respect to a putative connection of the
releases to recent warming in the region. In
fact, natural thawing mechanisms such as
geothermal heat and the 7 000 years of slow
warming from the overlying seawater are likely
to be the dominating factors. Nevertheless,
Participants (cont.)
magnus mörth*
Department of Geology and
Geochemistry, Stockholm University
leonid Polyak
ohio State University
Columbus, ohio, USA
don Porcelli
University of oxford
UK
* not participating in the field
Figure 2
The ISSS-08 cruise track starting
in Kirkenes and working through
the inner Barents – Kara – Laptev-
East Siberian and Chukchi Seas and
returning through mid shelf waters in
the East Siberian and Laptev Seas.
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