From Tim Page
      onboard RSV "Aurora Australis"
      being towed by "Shirase"
      Antarctica
      16th December 1998, 10pm
 

Hello again to everyone at Winthrop school, and welcome back to Ms Kelly!
 

PRESENT POSITION:   66 degrees South Latitude, 75 degrees East Longitude
DIRECTION HEADING:   359 degrees (North)
SPEED HEADING:   4.1 knots (4.7 miles per hour)
DISTANCE FROM DAVIS STATION: 142 nautical miles (163 miles)
DISTANCE TO FREMANTLE:  2543 nautical miles (2925 miles)
AIR TEMPERATURE:   -1.7 degrees Celsius (29 degrees Fahrenheit)
WATER TEMPERATURE:  -1.7 degrees Celsius (29 degrees Fahrenheit)
WATER DEPTH:   ??? (depth sounder not working)
WIND SPEED:    7 knots (8 miles per hour)
 
 

Hi there everyone.  Well a most amazing thing has happened, we're moving!!  Yipee!!  I thought we were going to be stuck in the same place forever!  Actually we were lucky since we were only stuck in the ice for 3 weeks.  The British explorer, Ernest Shackleton, was stuck in the ice for 10 months  and then his ship was crushed and sank!  A couple of days ago, I woke up, looked out the window, and there was another big, orange ship (our ship, the "Aurora Australis" is also orange).  It was the Japanese icebreaker, the "Shirase".  It was pretty cool, because the "Shirase" fired a rocket over to our ship, with a rope attached.  We then tied the line near the bow (front) of our ship, and the "Shirase" started towing us through the ice, a lot like a tow truck pulling a broken-down car that's been stuck in the snow.  They will tow us out to the edge of the ice, where we are going to be met by a South African ship, the "John Ross".  It is going to take us to the nearest port so they can fix our propeller.  The nearest dry dock (kind of like a garage for ships) is at Fremantle in the state of Western Australia (Latitude 32 degrees South, Longitude 115 degrees East).  Can you find it on a map?

Well, as you can probably imagine, one of the most important things scientists study down here in the Antarctic is ice.  Not surprising when there is so much of it here.  Ice is a very important part of the environment.  Animals live on it and under it.  The surface of  huge portions of the ocean becomes solid during the winter, and changes the environment for every plant and animal (people included!).  As you may have guessed by now, I've managed to talk another scientist into explaining their work.  Anne is a specialist on sea ice.  She has been on ships now for 100 days straight, so she has seen a whole lot of ice!  Here she goes:
 

"The freezing of the ocean - Antarctic sea-ice

As winter approaches in Antarctica the air temperature drops and the ocean water gets colder.  When the seawater temperature reaches -1.8 degrees Celsius, the sea begins to freeze.  The salt in the sea means the freezing temperature of seawater is lower than the freezing temperature of fresh water.  At what temperature does fresh water freeze?

When the sea starts to freeze, little crystals of ice form on the surface of the sea because this is where it is coldest.  This is the first stage of sea-ice formation and is called "frazil" ice.   Waves and wind on the sea surface move these little frazil crystals about and they bump into each other and stick together.  Soon they form the second stage of sea-ice development called "grease" ice.  This ice looks like slicks of grease (or oil) on the sea surface because it does not reflect light like water, and so looks dull in appearance.  The ice continues to grow and soon becomes a thin sheet of ice on the sea surface.  This is the third stage of sea-ice development and is called "nilas" ice.  This ice bends as small waves pass though the sea-ice area.  It is less than 10cm thick.  If big waves come through, the nilas ice can break.  The broken pieces bump together and become rounded in shape.  They look like pancakes all over the sea and this is called "pancake" ice.  The pancakes can be lots of different sizes, from 10cm in diameter to 10m in diameter.

Sea-ice forms over a very large part of the ocean surrounding Antarctica.  It eventually covers an area of about 20 million square kilometers.  What state is about this size?  All this ice starts to stop the swell and waves of the Southern Ocean reaching the coast of Antarctica.  This means the sea-ice near the land is able to grow thicker because it is not being broken up by waves anymore.  It grows in thickness; 10cm, 30cm, 50cm, 1m and may get up to 2m thick.  When snow falls it sits on top of the ice and if there is enough snow it may be heavy enough to partially sink the ice.

You could draw a picture showing the different stages of sea-ice development.

As sea-ice forms phytoplankton living in the sea surface become trapped in the forming ice.  Do you know what phytoplankton are?  They are single cell plants that float in the ocean making food by photosynthesis.  This is the process of using sunlight energy to make sugars out of carbon dioxide and water.  When the sea-ice becomes thick, it blocks out sunlight from the water below so by being in the ice the phytoplankton are able to keep making some food through the long, dark winter. Then, when the ice melts the next summer, the phytoplankton are released into the seawater and with all the summer sunshine are able to make lots of food, reproduce and continue their survival.  With the phytoplankton growing and making their own food in the summer time other animals come to feed on them, like little  animals called zooplankton, which are not much bigger than the phytoplankton they eat.  These are eaten by bigger animals like krill, which look similar to shrimps, and fish, penguins and flying birds.   All these animals are then food for even bigger animals like seals, other fish, penguins and flying birds.

The very big animals, the whales, are divided into two groups depending on what they eat.  One group is called the baleen whales and they only eat the small phytoplankton and krill.  The other group is called toothed whales and they eat the bigger animals like seals, penguins and fish.  Look at a picture of the mouths of these different whale groups to see why they eat different types of food.  This chain of feeding is called the food chain.  Have you heard of this before?  Around Antarctica it starts with phytoplankton that have survived the long winter in the sea-ice.  So the cycle of freezing and melting of the surface of the sea every year is very important to the lives of a lot of animals.  You could draw a picture of the food chain and how sea-ice plays an important role in it."
 

Thanks Anne, that was fantastic.  Ice really is important to all the creatures down here.  I managed to sucker (I mean "convince", of course) another scientist on our ship to write about ice.  His name is Joel, and he studies krill, but today he's going to talk about how you can use sound to study ice.  Here he goes:
 

"In the same way that dolphins, bats and whales use sound to "see" objects in the water, scientists in Antarctica use sound to "see" how deep the ice is, anywhere on the continent. By firing a powerful sound pulse into the ice and measuring how long it takes for the echo to return (it bounces back off the rock on which the ice sits), scientists can calculate how thick the ice is. They can do it because they know how fast sound travels through ice.

Similarly, Geoscientists can use sound to survey large areas for oil or natural gas. This is not done in Antarctica because the entire continent is protected from mining. Because sound travels at different speeds through rock, water, oil and natural gas, the pattern of echoes that come back can reveal what is down there and how far it is down.  In any area to be surveyed, the scientists will fire sound pulses in a search pattern, and mark all the returns they get on a map so that they finish up with a big picture of the whole area.  It's a bit like a doctor using ultrasound to "see" a baby while it's still inside the mother."
 

Thanks Joel.  He has promised to arrange an interview soon with the one krill we have on board (his name is Bill and he lives in a tank in one of the labs).

Today I will finish by answering some questions from Paul and Sam in Mrs O'Reilly's class.
 

1) "Have you seen any more animals yet?"

It has been a while since I have seen any new animals because we have been stopped for such a long time.  While we were stopped, I saw Adelie and Emperor Penguins, as well as Weddell Seals.  I did see one new animal, though.  I went on a helicopter flight over a patch of open water, where I saw five large grey-brown things just under the water.  They were the shape of torpedoes and bigger than Minke whales but smaller than Sperm Whales.  I'm not entirely sure what they were since they are different from any other whales I have ever seen.  My guess is that they were either Arnoux's Beaked Whales or Southern Bottlenose Whales, both of which are very rarely seen, so I was very lucky.

2) "What is the biggest animal you have seen?"

The biggest animal I have seen on this trip is a Sperm Whale.  They also look like torpedoes.  They are about 15 metres long (49 feet) and a full grown male weighs about 40 metric tonnes (about 44 tons).  That's really, really big.

3) "How big is the biggest iceberg you have you seen?"

The biggest one we've seen was a real monster.  It was 40 miles (64 kilometres) long and 22 miles (35 kilometres) wide, and 131 feet (40 metres) high!  Since most of an iceberg is below the surface, this one went about 1300 feet (400 metres) beneath the sea.  That too is really, really, really big!

4) "Has it snowed yet?"

Yes, it has snowed.  The whole ships looks great covered in snow.  Actually it hasn't snowed that much.  The continent itself gets very little precipitation (snow and rain) and so it is like a big, white desert.

5) "What's the temperature there?"

The temperature at the moment is 29 degrees Fahrenheit.  That's -1.7 degrees in the Celsius scale, which is the one most other countries use.  The coldest it has been so far for us has been -11 degrees Celsius (12 degrees Fahrenheit).  It gets much colder than that during the winter and further inland.  It can be -70 degrees Celsius (-94 degrees Fahrenheit) near the South Pole!  That is so cold that if you throw a glass of water into the air, it will be ice before it hits the ground!

6) "How cold is the water?"

Funnily enough, it's the same temperature as the air (see above).  Anne explained in her discussion of sea ice above how it can be colder than normal freezing temperature and still be liquid because it's salty.

7) "How big is your boat?"

Normally we call a large boat a "ship".  Our ship, the "Aurora Australis", is 94 metres long.  That is 308 feet long, but most countries use metres from the metric system instead of feet.  The Japanese ship that's towing us, the "Shirase" is 134 metres (439 feet) long.  The South African ship, the "John Ross", that we are going to meet at the ice edge in a couple days, is the same size as our ship.  If our ship is 94 metres long, how many Sperm Whales laid end to end would be about the same size?  If the iceberg was 64 kilometres long, how many Aurora Australis ships laid end to end would be about the same size?

8) "Do you have your own bathroom in your room?"

There is a bathroom in my cabin, which I share with a guy called Graham (nicknamed "Digger").  He has just finished spending a year in Antarctica at Mawson Station, looking after the big machines there, like bulldozers.

9) "Where are you now?"

Right now we are at Latitude 66 degrees South and Longitude 75 degrees East.  We are heading north, and should be out of the pack ice in a day or two.

10) "Do you like were you are?"

Yes, very very much.  Not many people get a chance to come down here, so I'm very lucky.  The ice is beautiful, and there are amazing animals everywhere, whales, seals, penguins.  It's almost like a paradise for me!

11) "How many people are on the boat?"

At the moment there are 96 people on board our ship.  24 of them are the ship's crew, and 30 of them are "round-trippers" (like me), who have spent the whole trip on the ship.  The rest of the people we picked up at the different bases after they finished working there.  How many of them are there?

12) "Do you miss your family?"

Yes, very much, but when I got the chance to come down here, I had to come.  I will be back soon.

13) "How do you keep in touch with your family?"

Mostly I have used email to keep in touch with my friends and family.  It has been very useful.  My mother, father, brother, grandparents and girlfriend all have access to email in their homes.  Our ship hooks up to a satellite twice a day and then we can send and receive email.  I have also been able to make a couple phone calls with a satellite telephone, but that's really expensive.

14) "Did you go fishing yet?"

I have not been fishing.  You see Antarctica is a nature reserve, so generally you aren't allowed to go fishing without a special scientific permit.  My friend, Joel (the krill man), has been fishing for krill using a net.  So far he's only been able to catch one (the famous "Bill the Krill" who you will meet next time).

They also sent me the first part of a joke, "Why don't polar bears eat penguins?"

I don't know the punch line, but I have a pretty good idea what it may refer to.  I guess I'll find out when they send me the rest of the joke.

That's all for now.  See you guys later.  I'll write again before you go on vacation next week.

Bye

Tim Page