Susan – this is for you and your homeschool lesson – tell Allison that there are lots of types of ice that form here. There is sea ice that forms when the sea freezes and can be as clear as crystal (which means there is no air in it), icebergs that calve off of glaciers (small one are called bergie bits and there is another name for the really small ones but I don’t remember it), and fast ice that is, I think, connected to land (stuck fast to the land). Pack ice is the big pieces floating around; lots of the wildlife here depends on the pack ice to hunt and rest. If it melts they will be in trouble.
If you licked an iceberg the water would be fresh water – the salt and other minerals concentrate and run out through little capillaries. The deep blue in the deepest part of the ice is so blue because all the air has been compressed out by the weight of the ice and so only blue light is reflected back while other wavelengths are absorbed. I know all this because the 5 or 6 onboard National Geographic naturalists told us so. We are travelling with a couple of bird guys, a marine mammal guy, a historian, a geologist and 4 or 5 of Nat Geo’s photographers. I’ll send you their names and you can look them and their work up on the Internet.
The picture of the ice hanging kind of into the ocean is the bottom of a glacier that will eventually calve. You can see the deep blue being reflected from the ice. The deep blue pointy iceberg is that color because it had been underwater, but when the weight of the iceberg changed this part popped up to the surface, again the color means there is no air in the ice. The bunches of little pieces of ice are sea ice and the picture was taken in the Lemaire Channel.
If you look at your map, the place we went in the water is in the caldera of an active volcano. That’s why the water was warm enough for us to go in, it’s being heated by the magma under the beach. The island is called Deception Island. Right now we are in the Drake Passage, which is open ocean and is supposed to be one of the roughest passages in the world. Lots of people are barfing and those that aren’t keep falling all over because the ship is rocking so much. It’s kind of like learning to dance with the ocean.
There are penguin researchers counting colonies from a group called Oceanites with us. They are doing colony counts to see which species of penguins are doing well and which ones are not. One of them is also using isotopes found in hatched penguin eggs to figure out what the diet of the adults is. Then they will use that information to help them figure out how the food chain in the area is changing. There is also a group of divers doing research on underwater plants and animals in the area. Both groups show us their research in the evenings. The penguin researchers say that Adelie penguin numbers are falling very quickly, partly because the only eat certain sized krill and only nest in the same places every year. The Gentoo penguins are doing really well, partly because they eat fish and all kinds of krill and they will move if the area they have been nesting in no longer suits them. One colony of Adelies we went to had almost no babies at all (there should have been 1 or 2 babies in every nest) and the researchers said that was not unusual.
