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Sept. 13, 2007
tHE SEA ICE IS GETTING
THINNER – A CLOSER LOOK
AT THE CLIMATE AND ECOSYSTEM OF THE ARCTIC OCEAN
Large areas of the Arctic sea-ice are only about 3.3 feet (1 meter)
meter thick
this year, equating to an approximate 50 percent thinning as compared
to the
year 2001. These are the initial results from the latest
Alfred-Wegener-Institute for Polar and Marine Research in the Helmholtz
Association lead expedition to the North Polar Sea.
50 scientists have been on board the Research ship- Polarstern for two
and a
half months, their main aim; to carry out research on the sea-ice areas
in the
central Arctic.
Amongst other things, they
have found out that not only the ocean currents are changing, but
community
structures in the Arctic
are also
altering. Autonomous measuring-buoys have been placed out, and
they will
contribute valuable data, also after the expedition is finished, to the
study
of the environmental changes occurring in this region.
“The ice cover in the North Polar Sea is dwindling, the ocean
and the
atmosphere are becoming steadily warmer, the ocean currents are
changing” said
chief scientist Dr Ursula Schauer, from the Alfred Wegener Institute
for Polar
and Marine Research part of the Helmholtz community, when commenting on
the
latest results from the current expedition. She is currently
in the
Arctic, underway with 50 Scientists from Germany,
Russia,
Finland,
the Netherlands,
Spain,
the USA,
Switzerland,
Japan,
France
and China,
where they are investigating
ocean and sea-ice conditions.
“We are in the midst of phase of dramatic change in the Arctic,
and the International Polar Year 2007/08 offers us a unique opportunity
to
study this dwindling ocean in collaboration with international
researchers”
said Schauer. Oceanographers on board the research ship
Polarstern are
investigating the composition and circulation of the water masses,
physical
characteristics of sea-ice and transport of biological and geochemical
components in ice and seawater. Sea-ice ecosystems in the seawater and
on the
ocean floor will also be a focus of investigations. Scientists
will take
sediments from the ocean floor in order to reconstruct the climatic
history of
the surrounding continents.
Oceanographic measuring buoys were set out in all
regions of the Arctic Ocean
for the first time
during this International Polar Year. They are able to drift
freely in the
Arctic Ocean whilst
collecting data on
currents, temperature, and salt content of the seawater. The buoys will
continuously collect data over and send them back to the scientists via
satellite.
In addition, the deployment of a new titanium measuring system which
allows
contamination free sample collection of trace elements for the first
time due
to its high effectiveness. These studies will take place
within the
context of different research projects, all taking place during the
International Polar Year: SPACE (Synoptic Pan-Arctic Climate
and
Environment Study), iAOOS (Integrated Arctic Ocean Observing System)
and GEOTRACES
(Trace Elements in the Arctic). At
the
same time, a large component of the work is supported by the European
Union
Program DAMOCLES (Developing Arctic Modelling and Observing
Capabilities for
Long-term Environment Studies).
Changes in Sea-Ice
The thickness of the arctic sea-ice has decreased since 1979, and at
the moment
measures about 3.3 feet (1 meter) in diameter in the central Arctic
Basin.
In addition, oceanographers have found a particularly high
concentration
of melt-water in the ocean and a large number of
melt-ponds. These data,
collected from on board the Polarstern, and also from helicopter
flights allow
the scientists to better interpret their satellite images.
Sea-Ice biologists from the Institute
of Polar Ecology
at the University
of Kiel
are studying the animals and plants
living in and beneath the ice. They are using the opportunity
to
investigate the threatened ecosystem. According to the newest
models, the
Arctic could be ice
free in less than 50 years
in case of further warming. This may cause the extinction of
many
organisms that are adapted to this habitat.
Ocean Currents
The Arctic Ocean
currents are an important
part of global ocean circulation. Warm water masses flowing in
from the
Atlantic are changed in the Arctic
through
water cooling and ice formation, and sink to great
depths. Constant monitoring
by the Alfred-Wegener-Institute for Polar and Marine Research over the
last ten
years have recorded significant changes, and have demonstrated a
warming of the
incoming current from the Atlantic
Ocean. During
this expedition, the propagation of these warming events along each of
the
currents in the North Polar Sea
will be investigated.
The large rivers of Siberia and North America transport huge amounts of
freshwater to the Arctic. The
freshwater
appears to function as an insulating layer, controlling the warmth
transfer
between the ocean, the ice and the atmosphere.
The study area stretches from the shelf areas of the Barents Sea, the Kara Sea and
the Laptev Sea, across Nansen and Amundsen bays right up to Makarow
Bay.
Between Norway
and Siberia
and up to the Canadian Bay the
scientists have
taken temperature, salinity, and current measurements at more than 100
places. First results have shown that the temperatures of the
influx of
water from the Atlantic
are lower as compared
to previous years. The temperatures and salinity levels in the Arctic
deep sea
are also slowly changing. The changes are small here, but the
areas go
down to great depths, and enormous water volumes are therefore
involved. In
order to follow the circulation patterns in winter, oceanographic
measuring
buoys will be attached to ice floes, and continuous measurements will
be taken
whilst they float along with the ice. The measurements will
be relayed
back via satellite.
In addition to the ocean currents and sea-ice, zooplankton, sediment
samples
from the sea floor as well as trace elements will be
taken. Zooplankton
are at the base of the food chain for many marine creatures, and are
therefore
an important indicator for the health of the ecosystem. The deposits
found on
the ocean floor of the North Polar Sea
read like a diary of the history of climate change for the surrounding
continents. Through sediment cores, the scientists may be able to
unlock the
key to the glaciation of northern Siberia.
In addition, the members of the expedition will be able to measure
trace
elements from Siberian rivers and shelf areas, that through polar drift
are
being pushed towards the Atlantic.
More information, visit:
www.awi.de/de/infrastruktur/schiffe/polarstern/wochenberichte/alle_expeditionen/ark_xxii/ark_xxii2/
##
Contact:
Angelika Dummermuth
Alfred Wegener Institute for Polar and Marine Research
49-471-483-11742
Angelika.Dummermuth@awi.de
This text derived from:
http://dailynews.mcmaster.ca/story.cfm?id=4896
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