Norbert Wu has spent a lot of time diving under the ice of Antarctica. Very dangerous, very interesting.

Despite the extreme cold, life is relatively abundant and he has some great photos.

Click through to the gallery for more pictures and explanations. Here are some of the best images.

Here a diver is swimming below a crack in the sea ice.

Starfish can be quite vicious. In this case they are slowly devouring a dead seal pup.

In Antarctica you don’t just dig a hole in the ice and start diving. They maintain ‘dive huts’ from which they dive in water as cold as -1.8 Centigrade.

Great idea – a portal and tube have been built to allow researchers to observe what is going on underwater.