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currents leads the driftwood in gyres and circles. While in open water the driftwood covers approximately
100 m per hour but great distances, brief open water seasons and the complicated routes of the sea
currents together produce very slow results. Therefore, it may take many decades for a given tree trunk
from Siberia to reach a Northeast Greenland coast as driftwood.
Danish Polar Center
IPY Service Manual for Kangerlussuaq 2008
version 1 June 2008
Compiled and written by Henning Thing (het@fi.dk)
Danish Polar Center Danish Agency for Science, Technology and Innovation
page 54 of 60
Ninety percent of the southbound water masses from the Arctic Ocean flow through the Fram Strait along
the north easternmost part of Greenland. This explains why the coasts and beaches in this part of the country
are so well stocked with branches and trunks of larch, birch, pine and spruce. Only 10 % of the driftwood
on these coasts originate from Canada, the rest comes from Siberia.
Polar Bear fur
We all know the polar bear. Its beautiful cream coloured fur is a trademark for this magnificent predator
whose home is the icy waters in the far north. The polar bear is just made for a life in cold and ice. Its fur
coat has an inner layer of fine curly wool and growing through the inner layer is a layer of stiff, shiny and
erect guard hairs. Both layers combined are only about 5 cm thick.
All polar bear hairs are colourless, but to the human eye the fur appears to be creamy-whitish in colour because
of the way the air-filled hairs reflect light. Long-term exposure to intense sunlight will eventually
change the hairs chemically so they get a yellowish colour. The polar bear has excellent buoyancy in water
because of the air-filled hairs that are also greasy, water repellent and non-matting whenever the fur is wet.
After a swim in icy water the polar bear just shakes vigorously and all water and ice disappear at once from
the fur.
It is a surprise to most that the skin of the polar bear is bluish-black. Because of this dark colour, the sun
light that does penetrate the fur and reaches the skin will be taken in as conductive radiation heat. The hollow
hairs are also act as insulators, but the best insulation of the body organs is provided by the up to 10
cm thick blubber layer that the polar bear has just beneath the skin. They easily overheat at temperatures
above 10°C and they are so well insulated that their breath and nose are the only things to be seen in an
infrared photography of a polar bear.
The polar bear is not the only one using its fur. In the hunting districts of Greenland polar bear fur pants are
still the very best personal garment on hunting trips. Polar bear fur trims are also à la mode for ornaments
on the top of kamik stockings and on skin mittens.
True and full-fledged fly fishermen around the globe buy small tufts of polar bear hairs. Tied as a irresistibly
delicious insect-like lure these polar bear hairs have the reputation of attracting any trout or salmon with a
good taste. Maybe this could be a new export article from Greenland: An average polar bear skin with fur
can be divided into 1000 pieces of 5 x 5 cm. These squares with the famous white fly fishing hair have a
current market price of 2 DKK / cm2 and therefore the fur of a polar bear could be worth 50.000 DKK if it
was sold piece by piece to fly fishing flies.
That s white gold !
Ice and water
Ice is frozen water. Why is ice lighter than water? Why do icebergs float? The reason is simple: Clean water
is heaviest and has its highest density at +4 C (i.e. 1 litre clean freshwater weighs 1000 grams). At colder
temperatures water expands and, therefore, gets a lower density until it goes into solid form (it freezes) at
0 C. One litre of clean ice weighs 917 grams. Glacial ice (e.g. ice bergs) includes small air bubbles and,
thus, 1 litre of glacial ice weighs around 900 grams. Seawater, in which icebergs float, also has 35 salts
dissolved so 1 litre of seawater weighs approx. 1025 grams. Therefore, the density difference between iceberg
and seawater is 900/1025 = 0.87, which means that 87% of an evenly shaped iceberg is under water
and 13% is above the waterline. A rule of thumb: 7/8 of a floating iceberg is invisible.
Each year Greenland s many glaciers produce 30.000-40.000 icebergs, half of them originate in the
Uummannaq and in the Disko Bay regions, especially Ilulissat Isfjord. All together production of 60 billion
tons! The biggest of the icebergs from the Disko Bay are HUGE things of about 30 million tons, but the bigDanish
Polar Center
IPY Service Manual for Kangerlussuaq 2008
version 1 June 2008
Compiled and written by Henning Thing (het@fi.dk)
Danish Polar Center Danish Agency for Science, Technology and Innovation
　
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