Submitted by Anonymous on Thu, 12/18/2008 - 12:41
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Oden Antarctic Expedition 08

Hi Mr Peneston! It's Dustin from Mr. Clancy's class. I have a question for you.

 

Here it is:

 

What kind of Ice are you hoping to find in Antarctica?

Are the crab eater seals going to die because of the dog dieases the snow dogs gave them? And is it getting hard for the seals to eat because of the disease?

Fri, 12/19/2008 - 10:20

Jeff Peneston

Dustin,These are 2 great questions and I think I am going to respond to them in my upcoming journal.
Types of Ice?There are many types of ice, especially on the “ice continent”.  Some of the major ice groups are crystal ice like snow and glacial ice, which forms on the continent from thousands of years of snow layers.  Then there are the ice shelves that form where the glaciers slide out onto and float on the sea.  The edges of these ice shelves eventually break off and float away as icebergs of freshwater ice.  They other big group of ice types is the sea ice.  In fact we have a whole book we use to identify the different types of sea ice.  Most sea ice starts out as a thin layer of freezing ocean surface.  As the frozen seawater layers thicken, snow falls on them and become part of the sea ice.  Storms break up these sea ice flows and then the shattered chunks refreeze into a jumbled pile of ice and snow that creates large, thick floes.  This is what we have been walking on and sampling.  Most of these sea ice floes melt during the brief Antarctic summer, but some areas have ice that has not melted for several years and this “multi-year” ice is very thick and complex in its structure.  On this mission we want to sample as many different types of sea ice as possible at this time of year when the sea ice is starting to break up.  My personal favorite ice so far is the blue, chunks of glacial ice that we see in the icebergs.  Yesterday, I walked about 1 km from the ship to reach a small iceberg that was frozen into the sea ice floe.
Crabeater Seal Health?In 1953 over 90% of the crabeater seals (millions of individuals) died in Antarctica because of an epidemic of canine distemper.  It is likely that this virus infected them from contact with sled dogs.  Today, no one is allowed to bring sled dogs or any animal to Antarctica.   After over 50 years, the population of crabeater seals appears to be fully recovered and there is some evidence that there may be more crabeaters here than ever before.  Since the crabeaters eat the same krill as the great whales, and since during the last century, humans severely hunted the great whales of Antarctica, the krill population now is very high.  It appears that the crabeater seals are responding to a record high food supply and we are seeing them all day long from the Oden.  One of the questions the seal research team has is they want to know how resistant the seals will be to the next disease epidemic.   I hope these long answers make sense.  Keep asking and I’ll keep writing back!
Take care, and have fun,
Jeff