Polarstern's 30th anniversary - What have we learned from scientific expeditions to the Antarctic?

DW: Dr. Gutt, you were in the Antarctica in March, actually. Do you already miss Antarctica?

Julian Gutt: I have a family at home and that brings you very fast back home again and there is no big adpaptation necessary again.

We actually heard about the circulation of the sea water. What would happen if there is no more cold water sinking down at Antarctica?

This supports the entire world's ocean circulation so finally this would also have consequences for us in Europe, the North Atlantic current system brings warm water to the coast of Europe and that would be reduced, probably.

So we should actually worry about the climate in Antarctica. We heard from your colleage that temperatures went up by three degrees, what will happen to Antarctica if that continues?

The sea ice is already melting in this area where this had been measured, this increase of three centigrades, other areas of the Antarctica are slightly cooling so it's a regional phenonemon. The sea ice is shrinking and...

Do you know about the mechanism behind, it's cooling here and it's warming up there?

It has to do with the o-zone hole, but it's very complex and the background is not yet well understood.

And you're a water biologist, what happens to the water animals if temperatures rise?

The crill populations are dramatically decreasing. Crill is a small crustacean and it's the main food source for whales, penguins and seals and they might suffer in the near future.

What does that mean, suffer? Do we have to fear that they become extinct?

Maybe not extinct, but the number of individuals will dramatically decrease. What is already observed, for example, for penguins.

But they have a chance to grow again, these populations, right? If there is more crill in the water again at some point.

If these physical phenonoma recover, if the air would become colder again.

What do you actually see on the sea flor?

This is a typical community at the sea floor, there are relatives of corals. They are filter feeders. But there is not enough light for growth of plants. There are sponges which are quite abundant and quite common in the Antarctic. There are brittle stars under the former ice shelf, which are deep sea life forms. They occur at two hundred metre depth and normally down to eight thousand metre. And thers are ascidians, they grow only there after the collapse of the ice shelf.

There's a big variety of different animals, right?

There are not many predators who feed on these animals, this is at least one explanation, and the water's very clean.

Do we have to fear that this ecosystem will collapse at some point if more ice melts?

At the moment we cannot expect a collapse, but it responds already to this environmental change where it happens at the Antarctic Peninsula.

(Interview: Ingolf Baur)